Massive power regression going 3.4->3.5

[Daniel Vetter]

On Tue, Aug 07, 2012 at 09:43:48PM +0100, James Bottomley wrote:
> On Sun, 2012-08-05 at 22:36 +0200, Daniel Vetter wrote:
> > On Wed, Aug 01, 2012 at 11:08:19AM +0100, James Bottomley wrote:
> > > On Wed, 2012-08-01 at 09:58 +0100, Chris Wilson wrote:
> > > > On Wed, 01 Aug 2012 09:45:04 +0100, James Bottomley  > > > HansenPartnership.com> wrote:
> > > > > On Wed, 2012-08-01 at 09:16 +0100, Chris Wilson wrote:
> > > > > > On Wed, 01 Aug 2012 09:06:12 +0100, James Bottomley 
> > > > > >  wrote:
> > > > > > > I got the attached to apply and it doesn't really improve the 
> > > > > > > idle power
> > > > > > > much (12.5W).
> > > > > > 
> > > > > > That's good to know. Next step is to try overriding i915.semaphores.
> > > > > > Can you please test with i915.semaphores=0 and i915.semaphores=1?
> > > > > 
> > > > > There's not much point doing i915_semaphores=1 since that's the 
> > > > > default
> > > > > on gen 6 hardware, but i915_semaphores=0 recovers and idle power of
> > > > > ~6.5W
> > > > 
> > > > It is only the default if iommu is off, and changing the default
> > > > was one of the side-effects of the patch you bisected.
> > > > 
> > > > Can you please login to the desktop, let it idle, record
> > > > /sys/kernel/debug/dri/0/i915_cur_delayinfo and .../i915_drpc_info.
> > > > Then trace-cmd record -e i915 sleep 10s, and follow up with a new pair
> > > > of /sys/kernel/debug/dri/0/i915_cur_delayinfo and .../i915_drpc_info.
> > > > 
> > > > This will let us see whether the pm counters are truly advancing and
> > > > what activity the driver is performing whilst idle.
> > > 
> > > OK, so here it is
> > > 
> > > James
> > 
> > Hm, if I haven't botched the math, you have a rc6 residency of about 320
> > seconds between the two cats of drpc_info. Can you please script this so
> > that we have exactly 10s in between? (Aside: 3.6 has a neat interface for
> > rc6 residency in sysfs ...)
> 
> You botched the maths, I think.  The three cats after the sleep was
> three up arrows ... if it went over 11s I'd be surprised.

Oops, indeed I've botched it. Redoing it you have an rc6 residency of
3.2s. Which is clearly not enough :(
> 
> > Also, you need to attach the output of trace-cmd report (like with perf),
> > so that we see the tracepoints in detail.
> 
> You mean you want the full trace.dat file rather than what the output
> summary says?  I can, but it's 800k compressed which is probably over
> the list limit ... I can upload it somewhere when I get back from
> holiday next Monday.

Well, I need the decoded stuff from trace report, but yeah, the entire
thing, please.

> > Another quick thing to confirm: What is the power consumption on the old
> > kernel when booting with i915.i915_semaphores=1?
> 
> It idles at around 13W, which means the history of the problem must be
> this:
> 
> What looks to have happened seems to be because of a merge failure in
> drm:
> 
> In 3.2 Keith Packard disabled semaphores on sandybridge with
> 
> commit ebbd857e6b9a92c0aff4aacd1b1d2361d888633e
> Author: Keith Packard 
> Date:   Mon Dec 26 17:02:10 2011 -0800
> 
> drm/i915: Disable semaphores by default on SNB
> 
> Because of an apparent bug causing a GPU hang.
> 
> I think this is what gave me the power savings in 3.4 when the PCI layer
> was ready for it.
> 
> It got re-enabled accidentally in 3.5 by a mismerge of 
> 
> commit 2911a35b2e4eb87ec48d03aeb11f019e51ae3c0d
> Author: Ben Widawsky 
> Date:   Thu Apr 5 14:47:36 2012 -0700
> 
> drm/i915: use semaphores for the display plane
> 
> Because that puts back the pre ebbd857e6b9a92c0aff4aacd1b1d2361d888633e
> semaphore enabling code, but in a different place, which is probably why
> it wasn't spotted, so semaphores got re-enabled on sandybridge.

Well, I wanted to enable semaphores by default for 3.5 anyway since we've
tracked down the root-cause of these hangs. So it got enabled in that
commit by accident due to a rebase goof-up, but it's not enabled by
accident in 3.5.

> Perhaps what we should be doing is verifying that semaphores aren't
> sucking the same 6W of power on ivybridge and if not, just re-disable
> them on sandybridge, since we'll have to do that anyway to re-apply the
> bug fix.

Ben has already been running around with a killawatt and we don't see any
additional power consumption and we can't even reproduce your results on
snb. The thing is we have two ways to synchronize the gpu engines:
- blocking the thread that submits the rendering for a new engine until
  all dependencies have completed rendering on other engines.
- not blocking the submitting process, but using hw semaphores.

In both cases (assuming userspace submits equal amounts of gpu rendering)
we keep the gpu out of rc6 while doing so, but without semaphores we also
wake up the cpu (we get tons of interrupts from the gpu when blocking,
which we otherwise disable) and generally stall userspace. So there's
something fishy going on your system.

To avoid botching up the math we have neat rc6 res

Re: Massive power regression going 3.4->3.5

[Daniel Vetter]

On Tue, Aug 07, 2012 at 09:43:48PM +0100, James Bottomley wrote:
> On Sun, 2012-08-05 at 22:36 +0200, Daniel Vetter wrote:
> > On Wed, Aug 01, 2012 at 11:08:19AM +0100, James Bottomley wrote:
> > > On Wed, 2012-08-01 at 09:58 +0100, Chris Wilson wrote:
> > > > On Wed, 01 Aug 2012 09:45:04 +0100, James Bottomley 
> > > >  wrote:
> > > > > On Wed, 2012-08-01 at 09:16 +0100, Chris Wilson wrote:
> > > > > > On Wed, 01 Aug 2012 09:06:12 +0100, James Bottomley 
> > > > > >  wrote:
> > > > > > > I got the attached to apply and it doesn't really improve the 
> > > > > > > idle power
> > > > > > > much (12.5W).
> > > > > > 
> > > > > > That's good to know. Next step is to try overriding i915.semaphores.
> > > > > > Can you please test with i915.semaphores=0 and i915.semaphores=1?
> > > > > 
> > > > > There's not much point doing i915_semaphores=1 since that's the 
> > > > > default
> > > > > on gen 6 hardware, but i915_semaphores=0 recovers and idle power of
> > > > > ~6.5W
> > > > 
> > > > It is only the default if iommu is off, and changing the default
> > > > was one of the side-effects of the patch you bisected.
> > > > 
> > > > Can you please login to the desktop, let it idle, record
> > > > /sys/kernel/debug/dri/0/i915_cur_delayinfo and .../i915_drpc_info.
> > > > Then trace-cmd record -e i915 sleep 10s, and follow up with a new pair
> > > > of /sys/kernel/debug/dri/0/i915_cur_delayinfo and .../i915_drpc_info.
> > > > 
> > > > This will let us see whether the pm counters are truly advancing and
> > > > what activity the driver is performing whilst idle.
> > > 
> > > OK, so here it is
> > > 
> > > James
> > 
> > Hm, if I haven't botched the math, you have a rc6 residency of about 320
> > seconds between the two cats of drpc_info. Can you please script this so
> > that we have exactly 10s in between? (Aside: 3.6 has a neat interface for
> > rc6 residency in sysfs ...)
> 
> You botched the maths, I think.  The three cats after the sleep was
> three up arrows ... if it went over 11s I'd be surprised.

Oops, indeed I've botched it. Redoing it you have an rc6 residency of
3.2s. Which is clearly not enough :(
> 
> > Also, you need to attach the output of trace-cmd report (like with perf),
> > so that we see the tracepoints in detail.
> 
> You mean you want the full trace.dat file rather than what the output
> summary says?  I can, but it's 800k compressed which is probably over
> the list limit ... I can upload it somewhere when I get back from
> holiday next Monday.

Well, I need the decoded stuff from trace report, but yeah, the entire
thing, please.

> > Another quick thing to confirm: What is the power consumption on the old
> > kernel when booting with i915.i915_semaphores=1?
> 
> It idles at around 13W, which means the history of the problem must be
> this:
> 
> What looks to have happened seems to be because of a merge failure in
> drm:
> 
> In 3.2 Keith Packard disabled semaphores on sandybridge with
> 
> commit ebbd857e6b9a92c0aff4aacd1b1d2361d888633e
> Author: Keith Packard 
> Date:   Mon Dec 26 17:02:10 2011 -0800
> 
> drm/i915: Disable semaphores by default on SNB
> 
> Because of an apparent bug causing a GPU hang.
> 
> I think this is what gave me the power savings in 3.4 when the PCI layer
> was ready for it.
> 
> It got re-enabled accidentally in 3.5 by a mismerge of 
> 
> commit 2911a35b2e4eb87ec48d03aeb11f019e51ae3c0d
> Author: Ben Widawsky 
> Date:   Thu Apr 5 14:47:36 2012 -0700
> 
> drm/i915: use semaphores for the display plane
> 
> Because that puts back the pre ebbd857e6b9a92c0aff4aacd1b1d2361d888633e
> semaphore enabling code, but in a different place, which is probably why
> it wasn't spotted, so semaphores got re-enabled on sandybridge.

Well, I wanted to enable semaphores by default for 3.5 anyway since we've
tracked down the root-cause of these hangs. So it got enabled in that
commit by accident due to a rebase goof-up, but it's not enabled by
accident in 3.5.

> Perhaps what we should be doing is verifying that semaphores aren't
> sucking the same 6W of power on ivybridge and if not, just re-disable
> them on sandybridge, since we'll have to do that anyway to re-apply the
> bug fix.

Ben has already been running around with a killawatt and we don't see any
additional power consumption and we can't even reproduce your results on
snb. The thing is we have two ways to synchronize the gpu engines:
- blocking the thread that submits the rendering for a new engine until
  all dependencies have completed rendering on other engines.
- not blocking the submitting process, but using hw semaphores.

In both cases (assuming userspace submits equal amounts of gpu rendering)
we keep the gpu out of rc6 while doing so, but without semaphores we also
wake up the cpu (we get tons of interrupts from the gpu when blocking,
which we otherwise disable) and generally stall userspace. So there's
something fishy going on your system.

To avoid botching up the math we have neat rc6 residency counters in
s

Massive power regression going 3.4->3.5

[James Bottomley]

On Sun, 2012-08-05 at 22:36 +0200, Daniel Vetter wrote:
> On Wed, Aug 01, 2012 at 11:08:19AM +0100, James Bottomley wrote:
> > On Wed, 2012-08-01 at 09:58 +0100, Chris Wilson wrote:
> > > On Wed, 01 Aug 2012 09:45:04 +0100, James Bottomley  > > HansenPartnership.com> wrote:
> > > > On Wed, 2012-08-01 at 09:16 +0100, Chris Wilson wrote:
> > > > > On Wed, 01 Aug 2012 09:06:12 +0100, James Bottomley  > > > > at HansenPartnership.com> wrote:
> > > > > > I got the attached to apply and it doesn't really improve the idle 
> > > > > > power
> > > > > > much (12.5W).
> > > > > 
> > > > > That's good to know. Next step is to try overriding i915.semaphores.
> > > > > Can you please test with i915.semaphores=0 and i915.semaphores=1?
> > > > 
> > > > There's not much point doing i915_semaphores=1 since that's the default
> > > > on gen 6 hardware, but i915_semaphores=0 recovers and idle power of
> > > > ~6.5W
> > > 
> > > It is only the default if iommu is off, and changing the default
> > > was one of the side-effects of the patch you bisected.
> > > 
> > > Can you please login to the desktop, let it idle, record
> > > /sys/kernel/debug/dri/0/i915_cur_delayinfo and .../i915_drpc_info.
> > > Then trace-cmd record -e i915 sleep 10s, and follow up with a new pair
> > > of /sys/kernel/debug/dri/0/i915_cur_delayinfo and .../i915_drpc_info.
> > > 
> > > This will let us see whether the pm counters are truly advancing and
> > > what activity the driver is performing whilst idle.
> > 
> > OK, so here it is
> > 
> > James
> 
> Hm, if I haven't botched the math, you have a rc6 residency of about 320
> seconds between the two cats of drpc_info. Can you please script this so
> that we have exactly 10s in between? (Aside: 3.6 has a neat interface for
> rc6 residency in sysfs ...)

You botched the maths, I think.  The three cats after the sleep was
three up arrows ... if it went over 11s I'd be surprised.

> Also, you need to attach the output of trace-cmd report (like with perf),
> so that we see the tracepoints in detail.

You mean you want the full trace.dat file rather than what the output
summary says?  I can, but it's 800k compressed which is probably over
the list limit ... I can upload it somewhere when I get back from
holiday next Monday.

> Another quick thing to confirm: What is the power consumption on the old
> kernel when booting with i915.i915_semaphores=1?

It idles at around 13W, which means the history of the problem must be
this:

What looks to have happened seems to be because of a merge failure in
drm:

In 3.2 Keith Packard disabled semaphores on sandybridge with

commit ebbd857e6b9a92c0aff4aacd1b1d2361d888633e
Author: Keith Packard 
Date:   Mon Dec 26 17:02:10 2011 -0800

drm/i915: Disable semaphores by default on SNB

Because of an apparent bug causing a GPU hang.

I think this is what gave me the power savings in 3.4 when the PCI layer
was ready for it.

It got re-enabled accidentally in 3.5 by a mismerge of 

commit 2911a35b2e4eb87ec48d03aeb11f019e51ae3c0d
Author: Ben Widawsky 
Date:   Thu Apr 5 14:47:36 2012 -0700

drm/i915: use semaphores for the display plane

Because that puts back the pre ebbd857e6b9a92c0aff4aacd1b1d2361d888633e
semaphore enabling code, but in a different place, which is probably why
it wasn't spotted, so semaphores got re-enabled on sandybridge.

Perhaps what we should be doing is verifying that semaphores aren't
sucking the same 6W of power on ivybridge and if not, just re-disable
them on sandybridge, since we'll have to do that anyway to re-apply the
bug fix.

James

Re: Massive power regression going 3.4->3.5

[Ben Widawsky]

On 2012-08-07 13:43, James Bottomley wrote:

On Sun, 2012-08-05 at 22:36 +0200, Daniel Vetter wrote:

On Wed, Aug 01, 2012 at 11:08:19AM +0100, James Bottomley wrote:
> On Wed, 2012-08-01 at 09:58 +0100, Chris Wilson wrote:
> > On Wed, 01 Aug 2012 09:45:04 +0100, James Bottomley 
 wrote:

> > > On Wed, 2012-08-01 at 09:16 +0100, Chris Wilson wrote:
> > > > On Wed, 01 Aug 2012 09:06:12 +0100, James Bottomley 
 wrote:
> > > > > I got the attached to apply and it doesn't really improve 
the idle power

> > > > > much (12.5W).
> > > >
> > > > That's good to know. Next step is to try overriding 
i915.semaphores.
> > > > Can you please test with i915.semaphores=0 and 
i915.semaphores=1?

> > >
> > > There's not much point doing i915_semaphores=1 since that's 
the default
> > > on gen 6 hardware, but i915_semaphores=0 recovers and idle 
power of

> > > ~6.5W
> >
> > It is only the default if iommu is off, and changing the default
> > was one of the side-effects of the patch you bisected.
> >
> > Can you please login to the desktop, let it idle, record
> > /sys/kernel/debug/dri/0/i915_cur_delayinfo and 
.../i915_drpc_info.
> > Then trace-cmd record -e i915 sleep 10s, and follow up with a 
new pair
> > of /sys/kernel/debug/dri/0/i915_cur_delayinfo and 
.../i915_drpc_info.

> >
> > This will let us see whether the pm counters are truly advancing 
and

> > what activity the driver is performing whilst idle.
>
> OK, so here it is
>
> James

Hm, if I haven't botched the math, you have a rc6 residency of about 
320
seconds between the two cats of drpc_info. Can you please script 
this so
that we have exactly 10s in between? (Aside: 3.6 has a neat 
interface for

rc6 residency in sysfs ...)


You botched the maths, I think.  The three cats after the sleep was
three up arrows ... if it went over 11s I'd be surprised.

Also, you need to attach the output of trace-cmd report (like with 
perf),

so that we see the tracepoints in detail.


You mean you want the full trace.dat file rather than what the output
summary says?  I can, but it's 800k compressed which is probably over
the list limit ... I can upload it somewhere when I get back from
holiday next Monday.

Another quick thing to confirm: What is the power consumption on the 
old

kernel when booting with i915.i915_semaphores=1?


It idles at around 13W, which means the history of the problem must 
be

this:

What looks to have happened seems to be because of a merge failure in
drm:

In 3.2 Keith Packard disabled semaphores on sandybridge with

commit ebbd857e6b9a92c0aff4aacd1b1d2361d888633e
Author: Keith Packard 
Date:   Mon Dec 26 17:02:10 2011 -0800

drm/i915: Disable semaphores by default on SNB

Because of an apparent bug causing a GPU hang.

I think this is what gave me the power savings in 3.4 when the PCI 
layer

was ready for it.

It got re-enabled accidentally in 3.5 by a mismerge of

commit 2911a35b2e4eb87ec48d03aeb11f019e51ae3c0d
Author: Ben Widawsky 
Date:   Thu Apr 5 14:47:36 2012 -0700

drm/i915: use semaphores for the display plane

Because that puts back the pre 
ebbd857e6b9a92c0aff4aacd1b1d2361d888633e
semaphore enabling code, but in a different place, which is probably 
why

it wasn't spotted, so semaphores got re-enabled on sandybridge.

Perhaps what we should be doing is verifying that semaphores aren't
sucking the same 6W of power on ivybridge and if not, just re-disable
them on sandybridge, since we'll have to do that anyway to re-apply 
the

bug fix.

James


Hi James. Would you mind filing a bug on this? In trying to reproduce 
this issue, I ran into another similar, but different issue ie. not 
resolved with semaphores=0. The issue I see can be reproduced with 
intel-gpu-tools/tests/sysfs_rc6_residency. That test is basically the 
same thing as what Chris/Daniel was asking for earlier with the drpc 
debugfs file info. In any case, it would be good to centralize all the 
data we've collected somewhere other than a mailing list/attachments.


http://intellinuxgraphics.org/how_to_report_bug.html

P.S. sorry if you already filed a bug somewhere earlier in the thread. 
I've been having mail problems.



--
Ben Widawsky, Intel Open Source Technology Center
___
dri-devel mailing list
dri-devel@lists.freedesktop.org
http://lists.freedesktop.org/mailman/listinfo/dri-devel

Massive power regression going 3.4->3.5

[Ben Widawsky]

On 2012-08-07 13:43, James Bottomley wrote:
> On Sun, 2012-08-05 at 22:36 +0200, Daniel Vetter wrote:
>> On Wed, Aug 01, 2012 at 11:08:19AM +0100, James Bottomley wrote:
>> > On Wed, 2012-08-01 at 09:58 +0100, Chris Wilson wrote:
>> > > On Wed, 01 Aug 2012 09:45:04 +0100, James Bottomley 
>>  wrote:
>> > > > On Wed, 2012-08-01 at 09:16 +0100, Chris Wilson wrote:
>> > > > > On Wed, 01 Aug 2012 09:06:12 +0100, James Bottomley 
>>  wrote:
>> > > > > > I got the attached to apply and it doesn't really improve 
>> the idle power
>> > > > > > much (12.5W).
>> > > > >
>> > > > > That's good to know. Next step is to try overriding 
>> i915.semaphores.
>> > > > > Can you please test with i915.semaphores=0 and 
>> i915.semaphores=1?
>> > > >
>> > > > There's not much point doing i915_semaphores=1 since that's 
>> the default
>> > > > on gen 6 hardware, but i915_semaphores=0 recovers and idle 
>> power of
>> > > > ~6.5W
>> > >
>> > > It is only the default if iommu is off, and changing the default
>> > > was one of the side-effects of the patch you bisected.
>> > >
>> > > Can you please login to the desktop, let it idle, record
>> > > /sys/kernel/debug/dri/0/i915_cur_delayinfo and 
>> .../i915_drpc_info.
>> > > Then trace-cmd record -e i915 sleep 10s, and follow up with a 
>> new pair
>> > > of /sys/kernel/debug/dri/0/i915_cur_delayinfo and 
>> .../i915_drpc_info.
>> > >
>> > > This will let us see whether the pm counters are truly advancing 
>> and
>> > > what activity the driver is performing whilst idle.
>> >
>> > OK, so here it is
>> >
>> > James
>>
>> Hm, if I haven't botched the math, you have a rc6 residency of about 
>> 320
>> seconds between the two cats of drpc_info. Can you please script 
>> this so
>> that we have exactly 10s in between? (Aside: 3.6 has a neat 
>> interface for
>> rc6 residency in sysfs ...)
>
> You botched the maths, I think.  The three cats after the sleep was
> three up arrows ... if it went over 11s I'd be surprised.
>
>> Also, you need to attach the output of trace-cmd report (like with 
>> perf),
>> so that we see the tracepoints in detail.
>
> You mean you want the full trace.dat file rather than what the output
> summary says?  I can, but it's 800k compressed which is probably over
> the list limit ... I can upload it somewhere when I get back from
> holiday next Monday.
>
>> Another quick thing to confirm: What is the power consumption on the 
>> old
>> kernel when booting with i915.i915_semaphores=1?
>
> It idles at around 13W, which means the history of the problem must 
> be
> this:
>
> What looks to have happened seems to be because of a merge failure in
> drm:
>
> In 3.2 Keith Packard disabled semaphores on sandybridge with
>
> commit ebbd857e6b9a92c0aff4aacd1b1d2361d888633e
> Author: Keith Packard 
> Date:   Mon Dec 26 17:02:10 2011 -0800
>
> drm/i915: Disable semaphores by default on SNB
>
> Because of an apparent bug causing a GPU hang.
>
> I think this is what gave me the power savings in 3.4 when the PCI 
> layer
> was ready for it.
>
> It got re-enabled accidentally in 3.5 by a mismerge of
>
> commit 2911a35b2e4eb87ec48d03aeb11f019e51ae3c0d
> Author: Ben Widawsky 
> Date:   Thu Apr 5 14:47:36 2012 -0700
>
> drm/i915: use semaphores for the display plane
>
> Because that puts back the pre 
> ebbd857e6b9a92c0aff4aacd1b1d2361d888633e
> semaphore enabling code, but in a different place, which is probably 
> why
> it wasn't spotted, so semaphores got re-enabled on sandybridge.
>
> Perhaps what we should be doing is verifying that semaphores aren't
> sucking the same 6W of power on ivybridge and if not, just re-disable
> them on sandybridge, since we'll have to do that anyway to re-apply 
> the
> bug fix.
>
> James

Hi James. Would you mind filing a bug on this? In trying to reproduce 
this issue, I ran into another similar, but different issue ie. not 
resolved with semaphores=0. The issue I see can be reproduced with 
intel-gpu-tools/tests/sysfs_rc6_residency. That test is basically the 
same thing as what Chris/Daniel was asking for earlier with the drpc 
debugfs file info. In any case, it would be good to centralize all the 
data we've collected somewhere other than a mailing list/attachments.

http://intellinuxgraphics.org/how_to_report_bug.html

P.S. sorry if you already filed a bug somewhere earlier in the thread. 
I've been having mail problems.


-- 
Ben Widawsky, Intel Open Source Technology Center

Re: Massive power regression going 3.4->3.5

[James Bottomley]

On Sun, 2012-08-05 at 22:36 +0200, Daniel Vetter wrote:
> On Wed, Aug 01, 2012 at 11:08:19AM +0100, James Bottomley wrote:
> > On Wed, 2012-08-01 at 09:58 +0100, Chris Wilson wrote:
> > > On Wed, 01 Aug 2012 09:45:04 +0100, James Bottomley 
> > >  wrote:
> > > > On Wed, 2012-08-01 at 09:16 +0100, Chris Wilson wrote:
> > > > > On Wed, 01 Aug 2012 09:06:12 +0100, James Bottomley 
> > > > >  wrote:
> > > > > > I got the attached to apply and it doesn't really improve the idle 
> > > > > > power
> > > > > > much (12.5W).
> > > > > 
> > > > > That's good to know. Next step is to try overriding i915.semaphores.
> > > > > Can you please test with i915.semaphores=0 and i915.semaphores=1?
> > > > 
> > > > There's not much point doing i915_semaphores=1 since that's the default
> > > > on gen 6 hardware, but i915_semaphores=0 recovers and idle power of
> > > > ~6.5W
> > > 
> > > It is only the default if iommu is off, and changing the default
> > > was one of the side-effects of the patch you bisected.
> > > 
> > > Can you please login to the desktop, let it idle, record
> > > /sys/kernel/debug/dri/0/i915_cur_delayinfo and .../i915_drpc_info.
> > > Then trace-cmd record -e i915 sleep 10s, and follow up with a new pair
> > > of /sys/kernel/debug/dri/0/i915_cur_delayinfo and .../i915_drpc_info.
> > > 
> > > This will let us see whether the pm counters are truly advancing and
> > > what activity the driver is performing whilst idle.
> > 
> > OK, so here it is
> > 
> > James
> 
> Hm, if I haven't botched the math, you have a rc6 residency of about 320
> seconds between the two cats of drpc_info. Can you please script this so
> that we have exactly 10s in between? (Aside: 3.6 has a neat interface for
> rc6 residency in sysfs ...)

You botched the maths, I think.  The three cats after the sleep was
three up arrows ... if it went over 11s I'd be surprised.

> Also, you need to attach the output of trace-cmd report (like with perf),
> so that we see the tracepoints in detail.

You mean you want the full trace.dat file rather than what the output
summary says?  I can, but it's 800k compressed which is probably over
the list limit ... I can upload it somewhere when I get back from
holiday next Monday.

> Another quick thing to confirm: What is the power consumption on the old
> kernel when booting with i915.i915_semaphores=1?

It idles at around 13W, which means the history of the problem must be
this:

What looks to have happened seems to be because of a merge failure in
drm:

In 3.2 Keith Packard disabled semaphores on sandybridge with

commit ebbd857e6b9a92c0aff4aacd1b1d2361d888633e
Author: Keith Packard 
Date:   Mon Dec 26 17:02:10 2011 -0800

drm/i915: Disable semaphores by default on SNB

Because of an apparent bug causing a GPU hang.

I think this is what gave me the power savings in 3.4 when the PCI layer
was ready for it.

It got re-enabled accidentally in 3.5 by a mismerge of 

commit 2911a35b2e4eb87ec48d03aeb11f019e51ae3c0d
Author: Ben Widawsky 
Date:   Thu Apr 5 14:47:36 2012 -0700

drm/i915: use semaphores for the display plane

Because that puts back the pre ebbd857e6b9a92c0aff4aacd1b1d2361d888633e
semaphore enabling code, but in a different place, which is probably why
it wasn't spotted, so semaphores got re-enabled on sandybridge.

Perhaps what we should be doing is verifying that semaphores aren't
sucking the same 6W of power on ivybridge and if not, just re-disable
them on sandybridge, since we'll have to do that anyway to re-apply the
bug fix.

James




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Massive power regression going 3.4->3.5

[Daniel Vetter]

On Wed, Aug 01, 2012 at 11:08:19AM +0100, James Bottomley wrote:
> On Wed, 2012-08-01 at 09:58 +0100, Chris Wilson wrote:
> > On Wed, 01 Aug 2012 09:45:04 +0100, James Bottomley  > HansenPartnership.com> wrote:
> > > On Wed, 2012-08-01 at 09:16 +0100, Chris Wilson wrote:
> > > > On Wed, 01 Aug 2012 09:06:12 +0100, James Bottomley  > > > HansenPartnership.com> wrote:
> > > > > I got the attached to apply and it doesn't really improve the idle 
> > > > > power
> > > > > much (12.5W).
> > > > 
> > > > That's good to know. Next step is to try overriding i915.semaphores.
> > > > Can you please test with i915.semaphores=0 and i915.semaphores=1?
> > > 
> > > There's not much point doing i915_semaphores=1 since that's the default
> > > on gen 6 hardware, but i915_semaphores=0 recovers and idle power of
> > > ~6.5W
> > 
> > It is only the default if iommu is off, and changing the default
> > was one of the side-effects of the patch you bisected.
> > 
> > Can you please login to the desktop, let it idle, record
> > /sys/kernel/debug/dri/0/i915_cur_delayinfo and .../i915_drpc_info.
> > Then trace-cmd record -e i915 sleep 10s, and follow up with a new pair
> > of /sys/kernel/debug/dri/0/i915_cur_delayinfo and .../i915_drpc_info.
> > 
> > This will let us see whether the pm counters are truly advancing and
> > what activity the driver is performing whilst idle.
> 
> OK, so here it is
> 
> James

Hm, if I haven't botched the math, you have a rc6 residency of about 320
seconds between the two cats of drpc_info. Can you please script this so
that we have exactly 10s in between? (Aside: 3.6 has a neat interface for
rc6 residency in sysfs ...)

Also, you need to attach the output of trace-cmd report (like with perf),
so that we see the tracepoints in detail.

Another quick thing to confirm: What is the power consumption on the old
kernel when booting with i915.i915_semaphores=1?

Thanks, Daniel
-- 
Daniel Vetter
Mail: daniel at ffwll.ch
Mobile: +41 (0)79 365 57 48

Re: Massive power regression going 3.4->3.5

[Daniel Vetter]

On Wed, Aug 01, 2012 at 11:08:19AM +0100, James Bottomley wrote:
> On Wed, 2012-08-01 at 09:58 +0100, Chris Wilson wrote:
> > On Wed, 01 Aug 2012 09:45:04 +0100, James Bottomley 
> >  wrote:
> > > On Wed, 2012-08-01 at 09:16 +0100, Chris Wilson wrote:
> > > > On Wed, 01 Aug 2012 09:06:12 +0100, James Bottomley 
> > > >  wrote:
> > > > > I got the attached to apply and it doesn't really improve the idle 
> > > > > power
> > > > > much (12.5W).
> > > > 
> > > > That's good to know. Next step is to try overriding i915.semaphores.
> > > > Can you please test with i915.semaphores=0 and i915.semaphores=1?
> > > 
> > > There's not much point doing i915_semaphores=1 since that's the default
> > > on gen 6 hardware, but i915_semaphores=0 recovers and idle power of
> > > ~6.5W
> > 
> > It is only the default if iommu is off, and changing the default
> > was one of the side-effects of the patch you bisected.
> > 
> > Can you please login to the desktop, let it idle, record
> > /sys/kernel/debug/dri/0/i915_cur_delayinfo and .../i915_drpc_info.
> > Then trace-cmd record -e i915 sleep 10s, and follow up with a new pair
> > of /sys/kernel/debug/dri/0/i915_cur_delayinfo and .../i915_drpc_info.
> > 
> > This will let us see whether the pm counters are truly advancing and
> > what activity the driver is performing whilst idle.
> 
> OK, so here it is
> 
> James

Hm, if I haven't botched the math, you have a rc6 residency of about 320
seconds between the two cats of drpc_info. Can you please script this so
that we have exactly 10s in between? (Aside: 3.6 has a neat interface for
rc6 residency in sysfs ...)

Also, you need to attach the output of trace-cmd report (like with perf),
so that we see the tracepoints in detail.

Another quick thing to confirm: What is the power consumption on the old
kernel when booting with i915.i915_semaphores=1?

Thanks, Daniel
-- 
Daniel Vetter
Mail: dan...@ffwll.ch
Mobile: +41 (0)79 365 57 48
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Re: Massive power regression going 3.4->3.5

[bwidawsk]

On 2012-08-01 03:06, Chris Wilson wrote:

On Wed, 01 Aug 2012 10:38:36 +0100, James Bottomley
 wrote:

On Wed, 2012-08-01 at 09:58 +0100, Chris Wilson wrote:
> On Wed, 01 Aug 2012 09:45:04 +0100, James Bottomley 
 wrote:

> > On Wed, 2012-08-01 at 09:16 +0100, Chris Wilson wrote:
> > > On Wed, 01 Aug 2012 09:06:12 +0100, James Bottomley 
 wrote:
> > > > I got the attached to apply and it doesn't really improve 
the idle power

> > > > much (12.5W).
> > >
> > > That's good to know. Next step is to try overriding 
i915.semaphores.
> > > Can you please test with i915.semaphores=0 and 
i915.semaphores=1?

> >
> > There's not much point doing i915_semaphores=1 since that's the 
default
> > on gen 6 hardware, but i915_semaphores=0 recovers and idle power 
of

> > ~6.5W
>
> It is only the default if iommu is off, and changing the default
> was one of the side-effects of the patch you bisected.
>
> Can you please login to the desktop, let it idle, record
> /sys/kernel/debug/dri/0/i915_cur_delayinfo and .../i915_drpc_info.
> Then trace-cmd record -e i915 sleep 10s,

OK, what is trace-cmd?  It looks similar to perf tools ... is that 
it?


Yes, it is roughly equivalent and you should be able to achieve the 
same
with perf trace - except I haven't done it before so I don't have 
quick

advice on how to drive it. :)
-Chris


Should be something like:
perf record -f -g -e i915:* -a
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Massive power regression going 3.4->3.5

[James Bottomley]

On Wed, 2012-08-01 at 22:08 -0700, bwidawsk wrote:
> On 2012-08-01 03:06, Chris Wilson wrote:
> > On Wed, 01 Aug 2012 10:38:36 +0100, James Bottomley
> >  wrote:
> >> On Wed, 2012-08-01 at 09:58 +0100, Chris Wilson wrote:
> >> > On Wed, 01 Aug 2012 09:45:04 +0100, James Bottomley 
> >>  wrote:
> >> > > On Wed, 2012-08-01 at 09:16 +0100, Chris Wilson wrote:
> >> > > > On Wed, 01 Aug 2012 09:06:12 +0100, James Bottomley 
> >>  wrote:
> >> > > > > I got the attached to apply and it doesn't really improve 
> >> the idle power
> >> > > > > much (12.5W).
> >> > > >
> >> > > > That's good to know. Next step is to try overriding 
> >> i915.semaphores.
> >> > > > Can you please test with i915.semaphores=0 and 
> >> i915.semaphores=1?
> >> > >
> >> > > There's not much point doing i915_semaphores=1 since that's the 
> >> default
> >> > > on gen 6 hardware, but i915_semaphores=0 recovers and idle power 
> >> of
> >> > > ~6.5W
> >> >
> >> > It is only the default if iommu is off, and changing the default
> >> > was one of the side-effects of the patch you bisected.
> >> >
> >> > Can you please login to the desktop, let it idle, record
> >> > /sys/kernel/debug/dri/0/i915_cur_delayinfo and .../i915_drpc_info.
> >> > Then trace-cmd record -e i915 sleep 10s,
> >>
> >> OK, what is trace-cmd?  It looks similar to perf tools ... is that 
> >> it?
> >
> > Yes, it is roughly equivalent and you should be able to achieve the 
> > same
> > with perf trace - except I haven't done it before so I don't have 
> > quick
> > advice on how to drive it. :)
> > -Chris
> 
> Should be something like:
> perf record -f -g -e i915:* -a

I already sent the output of trace-cmd ... is that enough?

James

Re: Massive power regression going 3.4->3.5

[Ben Widawsky]

On 2012-08-02 00:20, James Bottomley wrote:

On Wed, 2012-08-01 at 22:08 -0700, bwidawsk wrote:

On 2012-08-01 03:06, Chris Wilson wrote:
> On Wed, 01 Aug 2012 10:38:36 +0100, James Bottomley
>  wrote:
>> On Wed, 2012-08-01 at 09:58 +0100, Chris Wilson wrote:
>> > On Wed, 01 Aug 2012 09:45:04 +0100, James Bottomley
>>  wrote:
>> > > On Wed, 2012-08-01 at 09:16 +0100, Chris Wilson wrote:
>> > > > On Wed, 01 Aug 2012 09:06:12 +0100, James Bottomley
>>  wrote:
>> > > > > I got the attached to apply and it doesn't really improve
>> the idle power
>> > > > > much (12.5W).
>> > > >
>> > > > That's good to know. Next step is to try overriding
>> i915.semaphores.
>> > > > Can you please test with i915.semaphores=0 and
>> i915.semaphores=1?
>> > >
>> > > There's not much point doing i915_semaphores=1 since that's 
the

>> default
>> > > on gen 6 hardware, but i915_semaphores=0 recovers and idle 
power

>> of
>> > > ~6.5W
>> >
>> > It is only the default if iommu is off, and changing the 
default

>> > was one of the side-effects of the patch you bisected.
>> >
>> > Can you please login to the desktop, let it idle, record
>> > /sys/kernel/debug/dri/0/i915_cur_delayinfo and 
.../i915_drpc_info.

>> > Then trace-cmd record -e i915 sleep 10s,
>>
>> OK, what is trace-cmd?  It looks similar to perf tools ... is 
that

>> it?
>
> Yes, it is roughly equivalent and you should be able to achieve 
the

> same
> with perf trace - except I haven't done it before so I don't have
> quick
> advice on how to drive it. :)
> -Chris

Should be something like:
perf record -f -g -e i915:* -a


I already sent the output of trace-cmd ... is that enough?

James


Yes, should do. Have we already eliminated the obvious? GPU semaphores 
will
give time back to the GPU clients normally waiting on such things, X, 
XFCE,
whatever else. It'd probably be handy to begin investigating what those 
guys
are doing with their new extra time. Chris, this is what I was getting 
at on

IRC the other day. What do you think?

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Massive power regression going 3.4->3.5

[Ben Widawsky]

On 2012-08-02 00:20, James Bottomley wrote:
> On Wed, 2012-08-01 at 22:08 -0700, bwidawsk wrote:
>> On 2012-08-01 03:06, Chris Wilson wrote:
>> > On Wed, 01 Aug 2012 10:38:36 +0100, James Bottomley
>> >  wrote:
>> >> On Wed, 2012-08-01 at 09:58 +0100, Chris Wilson wrote:
>> >> > On Wed, 01 Aug 2012 09:45:04 +0100, James Bottomley
>> >>  wrote:
>> >> > > On Wed, 2012-08-01 at 09:16 +0100, Chris Wilson wrote:
>> >> > > > On Wed, 01 Aug 2012 09:06:12 +0100, James Bottomley
>> >>  wrote:
>> >> > > > > I got the attached to apply and it doesn't really improve
>> >> the idle power
>> >> > > > > much (12.5W).
>> >> > > >
>> >> > > > That's good to know. Next step is to try overriding
>> >> i915.semaphores.
>> >> > > > Can you please test with i915.semaphores=0 and
>> >> i915.semaphores=1?
>> >> > >
>> >> > > There's not much point doing i915_semaphores=1 since that's 
>> the
>> >> default
>> >> > > on gen 6 hardware, but i915_semaphores=0 recovers and idle 
>> power
>> >> of
>> >> > > ~6.5W
>> >> >
>> >> > It is only the default if iommu is off, and changing the 
>> default
>> >> > was one of the side-effects of the patch you bisected.
>> >> >
>> >> > Can you please login to the desktop, let it idle, record
>> >> > /sys/kernel/debug/dri/0/i915_cur_delayinfo and 
>> .../i915_drpc_info.
>> >> > Then trace-cmd record -e i915 sleep 10s,
>> >>
>> >> OK, what is trace-cmd?  It looks similar to perf tools ... is 
>> that
>> >> it?
>> >
>> > Yes, it is roughly equivalent and you should be able to achieve 
>> the
>> > same
>> > with perf trace - except I haven't done it before so I don't have
>> > quick
>> > advice on how to drive it. :)
>> > -Chris
>>
>> Should be something like:
>> perf record -f -g -e i915:* -a
>
> I already sent the output of trace-cmd ... is that enough?
>
> James

Yes, should do. Have we already eliminated the obvious? GPU semaphores 
will
give time back to the GPU clients normally waiting on such things, X, 
XFCE,
whatever else. It'd probably be handy to begin investigating what those 
guys
are doing with their new extra time. Chris, this is what I was getting 
at on
IRC the other day. What do you think?

Re: Massive power regression going 3.4->3.5

[James Bottomley]

On Wed, 2012-08-01 at 22:08 -0700, bwidawsk wrote:
> On 2012-08-01 03:06, Chris Wilson wrote:
> > On Wed, 01 Aug 2012 10:38:36 +0100, James Bottomley
> >  wrote:
> >> On Wed, 2012-08-01 at 09:58 +0100, Chris Wilson wrote:
> >> > On Wed, 01 Aug 2012 09:45:04 +0100, James Bottomley 
> >>  wrote:
> >> > > On Wed, 2012-08-01 at 09:16 +0100, Chris Wilson wrote:
> >> > > > On Wed, 01 Aug 2012 09:06:12 +0100, James Bottomley 
> >>  wrote:
> >> > > > > I got the attached to apply and it doesn't really improve 
> >> the idle power
> >> > > > > much (12.5W).
> >> > > >
> >> > > > That's good to know. Next step is to try overriding 
> >> i915.semaphores.
> >> > > > Can you please test with i915.semaphores=0 and 
> >> i915.semaphores=1?
> >> > >
> >> > > There's not much point doing i915_semaphores=1 since that's the 
> >> default
> >> > > on gen 6 hardware, but i915_semaphores=0 recovers and idle power 
> >> of
> >> > > ~6.5W
> >> >
> >> > It is only the default if iommu is off, and changing the default
> >> > was one of the side-effects of the patch you bisected.
> >> >
> >> > Can you please login to the desktop, let it idle, record
> >> > /sys/kernel/debug/dri/0/i915_cur_delayinfo and .../i915_drpc_info.
> >> > Then trace-cmd record -e i915 sleep 10s,
> >>
> >> OK, what is trace-cmd?  It looks similar to perf tools ... is that 
> >> it?
> >
> > Yes, it is roughly equivalent and you should be able to achieve the 
> > same
> > with perf trace - except I haven't done it before so I don't have 
> > quick
> > advice on how to drive it. :)
> > -Chris
> 
> Should be something like:
> perf record -f -g -e i915:* -a

I already sent the output of trace-cmd ... is that enough?

James


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Massive power regression going 3.4->3.5

[bwidawsk]

On 2012-08-01 03:06, Chris Wilson wrote:
> On Wed, 01 Aug 2012 10:38:36 +0100, James Bottomley
>  wrote:
>> On Wed, 2012-08-01 at 09:58 +0100, Chris Wilson wrote:
>> > On Wed, 01 Aug 2012 09:45:04 +0100, James Bottomley 
>>  wrote:
>> > > On Wed, 2012-08-01 at 09:16 +0100, Chris Wilson wrote:
>> > > > On Wed, 01 Aug 2012 09:06:12 +0100, James Bottomley 
>>  wrote:
>> > > > > I got the attached to apply and it doesn't really improve 
>> the idle power
>> > > > > much (12.5W).
>> > > >
>> > > > That's good to know. Next step is to try overriding 
>> i915.semaphores.
>> > > > Can you please test with i915.semaphores=0 and 
>> i915.semaphores=1?
>> > >
>> > > There's not much point doing i915_semaphores=1 since that's the 
>> default
>> > > on gen 6 hardware, but i915_semaphores=0 recovers and idle power 
>> of
>> > > ~6.5W
>> >
>> > It is only the default if iommu is off, and changing the default
>> > was one of the side-effects of the patch you bisected.
>> >
>> > Can you please login to the desktop, let it idle, record
>> > /sys/kernel/debug/dri/0/i915_cur_delayinfo and .../i915_drpc_info.
>> > Then trace-cmd record -e i915 sleep 10s,
>>
>> OK, what is trace-cmd?  It looks similar to perf tools ... is that 
>> it?
>
> Yes, it is roughly equivalent and you should be able to achieve the 
> same
> with perf trace - except I haven't done it before so I don't have 
> quick
> advice on how to drive it. :)
> -Chris

Should be something like:
perf record -f -g -e i915:* -a

Massive power regression going 3.4->3.5

[James Bottomley]

On Wed, 2012-08-01 at 09:58 +0100, Chris Wilson wrote:
> On Wed, 01 Aug 2012 09:45:04 +0100, James Bottomley  HansenPartnership.com> wrote:
> > On Wed, 2012-08-01 at 09:16 +0100, Chris Wilson wrote:
> > > On Wed, 01 Aug 2012 09:06:12 +0100, James Bottomley  > > HansenPartnership.com> wrote:
> > > > I got the attached to apply and it doesn't really improve the idle power
> > > > much (12.5W).
> > > 
> > > That's good to know. Next step is to try overriding i915.semaphores.
> > > Can you please test with i915.semaphores=0 and i915.semaphores=1?
> > 
> > There's not much point doing i915_semaphores=1 since that's the default
> > on gen 6 hardware, but i915_semaphores=0 recovers and idle power of
> > ~6.5W
> 
> It is only the default if iommu is off, and changing the default
> was one of the side-effects of the patch you bisected.
> 
> Can you please login to the desktop, let it idle, record
> /sys/kernel/debug/dri/0/i915_cur_delayinfo and .../i915_drpc_info.
> Then trace-cmd record -e i915 sleep 10s, and follow up with a new pair
> of /sys/kernel/debug/dri/0/i915_cur_delayinfo and .../i915_drpc_info.
> 
> This will let us see whether the pm counters are truly advancing and
> what activity the driver is performing whilst idle.

OK, so here it is

James

---

jejb at dabdike> cat /sys/kernel/debug/dri/0/i915_cur_delayinfo
GT_PERF_STATUS: 0x16c7
RPSTAT1: 0x0004160d
Render p-state ratio: 22
Render p-state VID: 199
Render p-state limit: 255
CAGF: 1100MHz
RP CUR UP EI: 96491us
RP CUR UP: 252us
RP PREV UP: 0us
RP CUR DOWN EI: 0us
RP CUR DOWN: 513us
RP PREV DOWN: 0us
Lowest (RPN) frequency: 650MHz
Nominal (RP1) frequency: 650MHz
Max non-overclocked (RP0) frequency: 1100MHz
jejb at dabdike> cat /sys/kernel/debug/dri/0/i915_drpc_info
RC information inaccurate because somebody holds a forcewake reference 
Video Turbo Mode: yes
HW control enabled: yes
SW control enabled: no
RC1e Enabled: no
RC6 Enabled: yes
Deep RC6 Enabled: no
Deepest RC6 Enabled: no
Current RC state: on
Core Power Down: no
RC6 "Locked to RPn" residency since boot: 0
RC6 residency since boot: 360123443
RC6+ residency since boot: 0
RC6++ residency since boot: 0
jejb at dabdike> ./git/trace-cmd/trace-cmd record -e i915 sleep 10s
trace-cmd: Permission denied
  opening '/sys/kernel/debug/tracing/tracing_on'
jejb at dabdike> sudo ./git/trace-cmd/trace-cmd record -e i915 sleep 10s
/sys/kernel/debug/tracing/events/i915/filter
/sys/kernel/debug/tracing/events/*/i915/filter
Kernel buffer statistics:
  Note: "entries" are the entries left in the kernel ring buffer and are not
recorded in the trace data. They should all be zero.

CPU: 0
entries: 0
overrun: 0
commit overrun: 0
bytes: 1080
oldest event ts:  1076.352744
now ts:  1076.651396

CPU: 1
entries: 0
overrun: 0
commit overrun: 0
bytes: 932
oldest event ts:  1067.676405
now ts:  1076.651452

CPU: 2
entries: 0
overrun: 0
commit overrun: 0
bytes: 3784
oldest event ts:  1076.090225
now ts:  1076.651501

CPU: 3
entries: 0
overrun: 0
commit overrun: 0
bytes: 0
oldest event ts: 15281105439.050279
now ts:  1076.651550

CPU0 data recorded at offset=0x39a000
221184 bytes in size
CPU1 data recorded at offset=0x3d
16384 bytes in size
CPU2 data recorded at offset=0x3d4000
32768 bytes in size
CPU3 data recorded at offset=0x3dc000
0 bytes in size
jejb at dabdike> cat /sys/kernel/debug/dri/0/i915_cur_delayinfo
GT_PERF_STATUS: 0x16c7
RPSTAT1: 0x0004160d
Render p-state ratio: 22
Render p-state VID: 199
Render p-state limit: 255
CAGF: 1100MHz
RP CUR UP EI: 49171us
RP CUR UP: 122us
RP PREV UP: 0us
RP CUR DOWN EI: 0us
RP CUR DOWN: 562us
RP PREV DOWN: 0us
Lowest (RPN) frequency: 650MHz
Nominal (RP1) frequency: 650MHz
Max non-overclocked (RP0) frequency: 1100MHz
jejb at dabdike> cat /sys/kernel/debug/dri/0/i915_drpc_info
RC information accurate: yes
Video Turbo Mode: yes
HW control enabled: yes
SW control enabled: no
RC1e Enabled: no
RC6 Enabled: yes
Deep RC6 Enabled: no
Deepest RC6 Enabled: no
Current RC state: RC6
Core Power Down: no
RC6 "Locked to RPn" residency since boot: 0
RC6 residency since boot: 362653127
RC6+ residency since boot: 0
RC6++ residency since boot: 0

Massive power regression going 3.4->3.5

[Chris Wilson]

On Wed, 01 Aug 2012 10:38:36 +0100, James Bottomley  wrote:
> On Wed, 2012-08-01 at 09:58 +0100, Chris Wilson wrote:
> > On Wed, 01 Aug 2012 09:45:04 +0100, James Bottomley  > HansenPartnership.com> wrote:
> > > On Wed, 2012-08-01 at 09:16 +0100, Chris Wilson wrote:
> > > > On Wed, 01 Aug 2012 09:06:12 +0100, James Bottomley  > > > HansenPartnership.com> wrote:
> > > > > I got the attached to apply and it doesn't really improve the idle 
> > > > > power
> > > > > much (12.5W).
> > > > 
> > > > That's good to know. Next step is to try overriding i915.semaphores.
> > > > Can you please test with i915.semaphores=0 and i915.semaphores=1?
> > > 
> > > There's not much point doing i915_semaphores=1 since that's the default
> > > on gen 6 hardware, but i915_semaphores=0 recovers and idle power of
> > > ~6.5W
> > 
> > It is only the default if iommu is off, and changing the default
> > was one of the side-effects of the patch you bisected.
> > 
> > Can you please login to the desktop, let it idle, record
> > /sys/kernel/debug/dri/0/i915_cur_delayinfo and .../i915_drpc_info.
> > Then trace-cmd record -e i915 sleep 10s,
> 
> OK, what is trace-cmd?  It looks similar to perf tools ... is that it?

Yes, it is roughly equivalent and you should be able to achieve the same
with perf trace - except I haven't done it before so I don't have quick
advice on how to drive it. :)
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre

Massive power regression going 3.4->3.5

[James Bottomley]

On Wed, 2012-08-01 at 09:58 +0100, Chris Wilson wrote:
> On Wed, 01 Aug 2012 09:45:04 +0100, James Bottomley  HansenPartnership.com> wrote:
> > On Wed, 2012-08-01 at 09:16 +0100, Chris Wilson wrote:
> > > On Wed, 01 Aug 2012 09:06:12 +0100, James Bottomley  > > HansenPartnership.com> wrote:
> > > > I got the attached to apply and it doesn't really improve the idle power
> > > > much (12.5W).
> > > 
> > > That's good to know. Next step is to try overriding i915.semaphores.
> > > Can you please test with i915.semaphores=0 and i915.semaphores=1?
> > 
> > There's not much point doing i915_semaphores=1 since that's the default
> > on gen 6 hardware, but i915_semaphores=0 recovers and idle power of
> > ~6.5W
> 
> It is only the default if iommu is off, and changing the default
> was one of the side-effects of the patch you bisected.
> 
> Can you please login to the desktop, let it idle, record
> /sys/kernel/debug/dri/0/i915_cur_delayinfo and .../i915_drpc_info.
> Then trace-cmd record -e i915 sleep 10s,

OK, what is trace-cmd?  It looks similar to perf tools ... is that it?

James


>  and follow up with a new pair
> of /sys/kernel/debug/dri/0/i915_cur_delayinfo and .../i915_drpc_info.
> 
> This will let us see whether the pm counters are truly advancing and
> what activity the driver is performing whilst idle.
> -Chris
> 

Massive power regression going 3.4->3.5

[Chris Wilson]

On Wed, 01 Aug 2012 10:07:23 +0100, James Bottomley  wrote:
> > Can you please login to the desktop, let it idle, record
> > /sys/kernel/debug/dri/0/i915_cur_delayinfo and .../i915_drpc_info.
> > Then trace-cmd record -e i915 sleep 10s, and follow up with a new pair
> > of /sys/kernel/debug/dri/0/i915_cur_delayinfo and .../i915_drpc_info.
> > 
> > This will let us see whether the pm counters are truly advancing and
> > what activity the driver is performing whilst idle.
> 
> With or without i915_semaphore=0?

With semaphores enabled so that we can see if they are active during the
idle period or if merely having used them at some point is enough to
trigger the issue. And to see if the pm counters bear any relation to
reality.
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre

Massive power regression going 3.4->3.5

[James Bottomley]

On Wed, 2012-08-01 at 09:58 +0100, Chris Wilson wrote:
> On Wed, 01 Aug 2012 09:45:04 +0100, James Bottomley  HansenPartnership.com> wrote:
> > On Wed, 2012-08-01 at 09:16 +0100, Chris Wilson wrote:
> > > On Wed, 01 Aug 2012 09:06:12 +0100, James Bottomley  > > HansenPartnership.com> wrote:
> > > > I got the attached to apply and it doesn't really improve the idle power
> > > > much (12.5W).
> > > 
> > > That's good to know. Next step is to try overriding i915.semaphores.
> > > Can you please test with i915.semaphores=0 and i915.semaphores=1?
> > 
> > There's not much point doing i915_semaphores=1 since that's the default
> > on gen 6 hardware, but i915_semaphores=0 recovers and idle power of
> > ~6.5W
> 
> It is only the default if iommu is off, and changing the default
> was one of the side-effects of the patch you bisected.

Sandybridge mobile doesn't have an iommu (or at least, if it does, the
kernel doesn't detect it).

> Can you please login to the desktop, let it idle, record
> /sys/kernel/debug/dri/0/i915_cur_delayinfo and .../i915_drpc_info.
> Then trace-cmd record -e i915 sleep 10s, and follow up with a new pair
> of /sys/kernel/debug/dri/0/i915_cur_delayinfo and .../i915_drpc_info.
> 
> This will let us see whether the pm counters are truly advancing and
> what activity the driver is performing whilst idle.

With or without i915_semaphore=0?

James

Massive power regression going 3.4->3.5

[Chris Wilson]

On Wed, 01 Aug 2012 09:45:04 +0100, James Bottomley  wrote:
> On Wed, 2012-08-01 at 09:16 +0100, Chris Wilson wrote:
> > On Wed, 01 Aug 2012 09:06:12 +0100, James Bottomley  > HansenPartnership.com> wrote:
> > > I got the attached to apply and it doesn't really improve the idle power
> > > much (12.5W).
> > 
> > That's good to know. Next step is to try overriding i915.semaphores.
> > Can you please test with i915.semaphores=0 and i915.semaphores=1?
> 
> There's not much point doing i915_semaphores=1 since that's the default
> on gen 6 hardware, but i915_semaphores=0 recovers and idle power of
> ~6.5W

It is only the default if iommu is off, and changing the default
was one of the side-effects of the patch you bisected.

Can you please login to the desktop, let it idle, record
/sys/kernel/debug/dri/0/i915_cur_delayinfo and .../i915_drpc_info.
Then trace-cmd record -e i915 sleep 10s, and follow up with a new pair
of /sys/kernel/debug/dri/0/i915_cur_delayinfo and .../i915_drpc_info.

This will let us see whether the pm counters are truly advancing and
what activity the driver is performing whilst idle.
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre

Massive power regression going 3.4->3.5

[James Bottomley]

On Wed, 2012-08-01 at 09:16 +0100, Chris Wilson wrote:
> On Wed, 01 Aug 2012 09:06:12 +0100, James Bottomley  HansenPartnership.com> wrote:
> > I got the attached to apply and it doesn't really improve the idle power
> > much (12.5W).
> 
> That's good to know. Next step is to try overriding i915.semaphores.
> Can you please test with i915.semaphores=0 and i915.semaphores=1?

There's not much point doing i915_semaphores=1 since that's the default
on gen 6 hardware, but i915_semaphores=0 recovers and idle power of
~6.5W

James

Massive power regression going 3.4->3.5

[Chris Wilson]

On Wed, 01 Aug 2012 09:06:12 +0100, James Bottomley  wrote:
> I got the attached to apply and it doesn't really improve the idle power
> much (12.5W).

That's good to know. Next step is to try overriding i915.semaphores.
Can you please test with i915.semaphores=0 and i915.semaphores=1?
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre

Massive power regression going 3.4->3.5

[James Bottomley]

On Tue, 2012-07-31 at 20:24 +0100, Chris Wilson wrote:
> On Tue, 31 Jul 2012 11:14:17 +0100, Chris Wilson  chris-wilson.co.uk> wrote:
> > On Tue, 31 Jul 2012 10:57:10 +0100, James Bottomley  > HansenPartnership.com> wrote:
> > > > When did you inspect the debug files? One effect I can imagine is that
> > > > if your system was previously stuck at RPn and never upclocking the GPU
> > > > when X starts. The question would then be what is preventing the GPU
> > > > from reaching its lowest power state again.
> > > 
> > > After I logged into an xfce4 session and powertop showed idle had been
> > > reached.
> 
> That you are using xfce4 makes the use of semaphores for pageflips as
> being the root cause even more suspect. Pageflips are only used for a
> fullscreen DRI client caalling SwapBuffers, to my knowledge xfce4 does
> not use DRI at all - its compositing manager is XRender based if you
> happen to be using it.
> 
> Please can you try the small patch to disable the use of semaphores for
> pageflips and see if the regression remains (which I judge it will...):
> 
> diff --git a/drivers/gpu/drm/i915/i915_gem.c
> b/drivers/gpu/drm/i915/i915_gem.c
> index 5c4657a..f301f2f 100644
> --- a/drivers/gpu/drm/i915/i915_gem.c
> +++ b/drivers/gpu/drm/i915/i915_gem.c
> @@ -3067,7 +3067,7 @@ i915_gem_object_pin_to_display_plane(struct 
> drm_i915_gem_o
> return ret;
>  
> if (pipelined != obj->ring) {
> -   ret = i915_gem_object_sync(obj, pipelined);
> +   ret = i915_gem_object_wait_rendering(obj);
> if (ret)
> return ret;
> }

Your patch doesn't apply ... I think because in v3.5 this line is
displaced by about 200 lines in the file.

patching file drivers/gpu/drm/i915/i915_gem.c
Hunk #1 FAILED at 3067.
1 out of 1 hunk FAILED -- saving rejects to file
drivers/gpu/drm/i915/i915_gem.c.rej

I got the attached to apply and it doesn't really improve the idle power
much (12.5W).

James

---

diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index 288d7b8..2f3f279 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -2869,7 +2869,7 @@ i915_gem_object_pin_to_display_plane(struct 
drm_i915_gem_object *obj,
return ret;

if (pipelined != obj->ring) {
-   ret = i915_gem_object_sync(obj, pipelined);
+   ret = i915_gem_object_wait_rendering(obj);
if (ret)
return ret;
}

Re: Massive power regression going 3.4->3.5

[James Bottomley]

On Wed, 2012-08-01 at 09:58 +0100, Chris Wilson wrote:
> On Wed, 01 Aug 2012 09:45:04 +0100, James Bottomley 
>  wrote:
> > On Wed, 2012-08-01 at 09:16 +0100, Chris Wilson wrote:
> > > On Wed, 01 Aug 2012 09:06:12 +0100, James Bottomley 
> > >  wrote:
> > > > I got the attached to apply and it doesn't really improve the idle power
> > > > much (12.5W).
> > > 
> > > That's good to know. Next step is to try overriding i915.semaphores.
> > > Can you please test with i915.semaphores=0 and i915.semaphores=1?
> > 
> > There's not much point doing i915_semaphores=1 since that's the default
> > on gen 6 hardware, but i915_semaphores=0 recovers and idle power of
> > ~6.5W
> 
> It is only the default if iommu is off, and changing the default
> was one of the side-effects of the patch you bisected.
> 
> Can you please login to the desktop, let it idle, record
> /sys/kernel/debug/dri/0/i915_cur_delayinfo and .../i915_drpc_info.
> Then trace-cmd record -e i915 sleep 10s, and follow up with a new pair
> of /sys/kernel/debug/dri/0/i915_cur_delayinfo and .../i915_drpc_info.
> 
> This will let us see whether the pm counters are truly advancing and
> what activity the driver is performing whilst idle.

OK, so here it is

James

---

jejb@dabdike> cat /sys/kernel/debug/dri/0/i915_cur_delayinfo
GT_PERF_STATUS: 0x16c7
RPSTAT1: 0x0004160d
Render p-state ratio: 22
Render p-state VID: 199
Render p-state limit: 255
CAGF: 1100MHz
RP CUR UP EI: 96491us
RP CUR UP: 252us
RP PREV UP: 0us
RP CUR DOWN EI: 0us
RP CUR DOWN: 513us
RP PREV DOWN: 0us
Lowest (RPN) frequency: 650MHz
Nominal (RP1) frequency: 650MHz
Max non-overclocked (RP0) frequency: 1100MHz
jejb@dabdike> cat /sys/kernel/debug/dri/0/i915_drpc_info
RC information inaccurate because somebody holds a forcewake reference 
Video Turbo Mode: yes
HW control enabled: yes
SW control enabled: no
RC1e Enabled: no
RC6 Enabled: yes
Deep RC6 Enabled: no
Deepest RC6 Enabled: no
Current RC state: on
Core Power Down: no
RC6 "Locked to RPn" residency since boot: 0
RC6 residency since boot: 360123443
RC6+ residency since boot: 0
RC6++ residency since boot: 0
jejb@dabdike> ./git/trace-cmd/trace-cmd record -e i915 sleep 10s
trace-cmd: Permission denied
  opening '/sys/kernel/debug/tracing/tracing_on'
jejb@dabdike> sudo ./git/trace-cmd/trace-cmd record -e i915 sleep 10s
/sys/kernel/debug/tracing/events/i915/filter
/sys/kernel/debug/tracing/events/*/i915/filter
Kernel buffer statistics:
  Note: "entries" are the entries left in the kernel ring buffer and are not
recorded in the trace data. They should all be zero.

CPU: 0
entries: 0
overrun: 0
commit overrun: 0
bytes: 1080
oldest event ts:  1076.352744
now ts:  1076.651396

CPU: 1
entries: 0
overrun: 0
commit overrun: 0
bytes: 932
oldest event ts:  1067.676405
now ts:  1076.651452

CPU: 2
entries: 0
overrun: 0
commit overrun: 0
bytes: 3784
oldest event ts:  1076.090225
now ts:  1076.651501

CPU: 3
entries: 0
overrun: 0
commit overrun: 0
bytes: 0
oldest event ts: 15281105439.050279
now ts:  1076.651550

CPU0 data recorded at offset=0x39a000
221184 bytes in size
CPU1 data recorded at offset=0x3d
16384 bytes in size
CPU2 data recorded at offset=0x3d4000
32768 bytes in size
CPU3 data recorded at offset=0x3dc000
0 bytes in size
jejb@dabdike> cat /sys/kernel/debug/dri/0/i915_cur_delayinfo
GT_PERF_STATUS: 0x16c7
RPSTAT1: 0x0004160d
Render p-state ratio: 22
Render p-state VID: 199
Render p-state limit: 255
CAGF: 1100MHz
RP CUR UP EI: 49171us
RP CUR UP: 122us
RP PREV UP: 0us
RP CUR DOWN EI: 0us
RP CUR DOWN: 562us
RP PREV DOWN: 0us
Lowest (RPN) frequency: 650MHz
Nominal (RP1) frequency: 650MHz
Max non-overclocked (RP0) frequency: 1100MHz
jejb@dabdike> cat /sys/kernel/debug/dri/0/i915_drpc_info
RC information accurate: yes
Video Turbo Mode: yes
HW control enabled: yes
SW control enabled: no
RC1e Enabled: no
RC6 Enabled: yes
Deep RC6 Enabled: no
Deepest RC6 Enabled: no
Current RC state: RC6
Core Power Down: no
RC6 "Locked to RPn" residency since boot: 0
RC6 residency since boot: 362653127
RC6+ residency since boot: 0
RC6++ residency since boot: 0


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Re: Massive power regression going 3.4->3.5

[Chris Wilson]

On Wed, 01 Aug 2012 10:38:36 +0100, James Bottomley 
 wrote:
> On Wed, 2012-08-01 at 09:58 +0100, Chris Wilson wrote:
> > On Wed, 01 Aug 2012 09:45:04 +0100, James Bottomley 
> >  wrote:
> > > On Wed, 2012-08-01 at 09:16 +0100, Chris Wilson wrote:
> > > > On Wed, 01 Aug 2012 09:06:12 +0100, James Bottomley 
> > > >  wrote:
> > > > > I got the attached to apply and it doesn't really improve the idle 
> > > > > power
> > > > > much (12.5W).
> > > > 
> > > > That's good to know. Next step is to try overriding i915.semaphores.
> > > > Can you please test with i915.semaphores=0 and i915.semaphores=1?
> > > 
> > > There's not much point doing i915_semaphores=1 since that's the default
> > > on gen 6 hardware, but i915_semaphores=0 recovers and idle power of
> > > ~6.5W
> > 
> > It is only the default if iommu is off, and changing the default
> > was one of the side-effects of the patch you bisected.
> > 
> > Can you please login to the desktop, let it idle, record
> > /sys/kernel/debug/dri/0/i915_cur_delayinfo and .../i915_drpc_info.
> > Then trace-cmd record -e i915 sleep 10s,
> 
> OK, what is trace-cmd?  It looks similar to perf tools ... is that it?

Yes, it is roughly equivalent and you should be able to achieve the same
with perf trace - except I haven't done it before so I don't have quick
advice on how to drive it. :)
-Chris

-- 
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Re: Massive power regression going 3.4->3.5

[James Bottomley]

On Wed, 2012-08-01 at 09:58 +0100, Chris Wilson wrote:
> On Wed, 01 Aug 2012 09:45:04 +0100, James Bottomley 
>  wrote:
> > On Wed, 2012-08-01 at 09:16 +0100, Chris Wilson wrote:
> > > On Wed, 01 Aug 2012 09:06:12 +0100, James Bottomley 
> > >  wrote:
> > > > I got the attached to apply and it doesn't really improve the idle power
> > > > much (12.5W).
> > > 
> > > That's good to know. Next step is to try overriding i915.semaphores.
> > > Can you please test with i915.semaphores=0 and i915.semaphores=1?
> > 
> > There's not much point doing i915_semaphores=1 since that's the default
> > on gen 6 hardware, but i915_semaphores=0 recovers and idle power of
> > ~6.5W
> 
> It is only the default if iommu is off, and changing the default
> was one of the side-effects of the patch you bisected.
> 
> Can you please login to the desktop, let it idle, record
> /sys/kernel/debug/dri/0/i915_cur_delayinfo and .../i915_drpc_info.
> Then trace-cmd record -e i915 sleep 10s,

OK, what is trace-cmd?  It looks similar to perf tools ... is that it?

James


>  and follow up with a new pair
> of /sys/kernel/debug/dri/0/i915_cur_delayinfo and .../i915_drpc_info.
> 
> This will let us see whether the pm counters are truly advancing and
> what activity the driver is performing whilst idle.
> -Chris
> 


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Re: Massive power regression going 3.4->3.5

[Chris Wilson]

On Wed, 01 Aug 2012 10:07:23 +0100, James Bottomley 
 wrote:
> > Can you please login to the desktop, let it idle, record
> > /sys/kernel/debug/dri/0/i915_cur_delayinfo and .../i915_drpc_info.
> > Then trace-cmd record -e i915 sleep 10s, and follow up with a new pair
> > of /sys/kernel/debug/dri/0/i915_cur_delayinfo and .../i915_drpc_info.
> > 
> > This will let us see whether the pm counters are truly advancing and
> > what activity the driver is performing whilst idle.
> 
> With or without i915_semaphore=0?

With semaphores enabled so that we can see if they are active during the
idle period or if merely having used them at some point is enough to
trigger the issue. And to see if the pm counters bear any relation to
reality.
-Chris

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Re: Massive power regression going 3.4->3.5

[James Bottomley]

On Wed, 2012-08-01 at 09:58 +0100, Chris Wilson wrote:
> On Wed, 01 Aug 2012 09:45:04 +0100, James Bottomley 
>  wrote:
> > On Wed, 2012-08-01 at 09:16 +0100, Chris Wilson wrote:
> > > On Wed, 01 Aug 2012 09:06:12 +0100, James Bottomley 
> > >  wrote:
> > > > I got the attached to apply and it doesn't really improve the idle power
> > > > much (12.5W).
> > > 
> > > That's good to know. Next step is to try overriding i915.semaphores.
> > > Can you please test with i915.semaphores=0 and i915.semaphores=1?
> > 
> > There's not much point doing i915_semaphores=1 since that's the default
> > on gen 6 hardware, but i915_semaphores=0 recovers and idle power of
> > ~6.5W
> 
> It is only the default if iommu is off, and changing the default
> was one of the side-effects of the patch you bisected.

Sandybridge mobile doesn't have an iommu (or at least, if it does, the
kernel doesn't detect it).

> Can you please login to the desktop, let it idle, record
> /sys/kernel/debug/dri/0/i915_cur_delayinfo and .../i915_drpc_info.
> Then trace-cmd record -e i915 sleep 10s, and follow up with a new pair
> of /sys/kernel/debug/dri/0/i915_cur_delayinfo and .../i915_drpc_info.
> 
> This will let us see whether the pm counters are truly advancing and
> what activity the driver is performing whilst idle.

With or without i915_semaphore=0?

James


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Re: Massive power regression going 3.4->3.5

[Chris Wilson]

On Wed, 01 Aug 2012 09:45:04 +0100, James Bottomley 
 wrote:
> On Wed, 2012-08-01 at 09:16 +0100, Chris Wilson wrote:
> > On Wed, 01 Aug 2012 09:06:12 +0100, James Bottomley 
> >  wrote:
> > > I got the attached to apply and it doesn't really improve the idle power
> > > much (12.5W).
> > 
> > That's good to know. Next step is to try overriding i915.semaphores.
> > Can you please test with i915.semaphores=0 and i915.semaphores=1?
> 
> There's not much point doing i915_semaphores=1 since that's the default
> on gen 6 hardware, but i915_semaphores=0 recovers and idle power of
> ~6.5W

It is only the default if iommu is off, and changing the default
was one of the side-effects of the patch you bisected.

Can you please login to the desktop, let it idle, record
/sys/kernel/debug/dri/0/i915_cur_delayinfo and .../i915_drpc_info.
Then trace-cmd record -e i915 sleep 10s, and follow up with a new pair
of /sys/kernel/debug/dri/0/i915_cur_delayinfo and .../i915_drpc_info.

This will let us see whether the pm counters are truly advancing and
what activity the driver is performing whilst idle.
-Chris

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Re: Massive power regression going 3.4->3.5

[James Bottomley]

On Wed, 2012-08-01 at 09:16 +0100, Chris Wilson wrote:
> On Wed, 01 Aug 2012 09:06:12 +0100, James Bottomley 
>  wrote:
> > I got the attached to apply and it doesn't really improve the idle power
> > much (12.5W).
> 
> That's good to know. Next step is to try overriding i915.semaphores.
> Can you please test with i915.semaphores=0 and i915.semaphores=1?

There's not much point doing i915_semaphores=1 since that's the default
on gen 6 hardware, but i915_semaphores=0 recovers and idle power of
~6.5W

James


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Re: Massive power regression going 3.4->3.5

[Chris Wilson]

On Wed, 01 Aug 2012 09:06:12 +0100, James Bottomley 
 wrote:
> I got the attached to apply and it doesn't really improve the idle power
> much (12.5W).

That's good to know. Next step is to try overriding i915.semaphores.
Can you please test with i915.semaphores=0 and i915.semaphores=1?
-Chris

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Re: Massive power regression going 3.4->3.5

[James Bottomley]

On Tue, 2012-07-31 at 20:24 +0100, Chris Wilson wrote:
> On Tue, 31 Jul 2012 11:14:17 +0100, Chris Wilson  
> wrote:
> > On Tue, 31 Jul 2012 10:57:10 +0100, James Bottomley 
> >  wrote:
> > > > When did you inspect the debug files? One effect I can imagine is that
> > > > if your system was previously stuck at RPn and never upclocking the GPU
> > > > when X starts. The question would then be what is preventing the GPU
> > > > from reaching its lowest power state again.
> > > 
> > > After I logged into an xfce4 session and powertop showed idle had been
> > > reached.
> 
> That you are using xfce4 makes the use of semaphores for pageflips as
> being the root cause even more suspect. Pageflips are only used for a
> fullscreen DRI client caalling SwapBuffers, to my knowledge xfce4 does
> not use DRI at all - its compositing manager is XRender based if you
> happen to be using it.
> 
> Please can you try the small patch to disable the use of semaphores for
> pageflips and see if the regression remains (which I judge it will...):
> 
> diff --git a/drivers/gpu/drm/i915/i915_gem.c
> b/drivers/gpu/drm/i915/i915_gem.c
> index 5c4657a..f301f2f 100644
> --- a/drivers/gpu/drm/i915/i915_gem.c
> +++ b/drivers/gpu/drm/i915/i915_gem.c
> @@ -3067,7 +3067,7 @@ i915_gem_object_pin_to_display_plane(struct 
> drm_i915_gem_o
> return ret;
>  
> if (pipelined != obj->ring) {
> -   ret = i915_gem_object_sync(obj, pipelined);
> +   ret = i915_gem_object_wait_rendering(obj);
> if (ret)
> return ret;
> }

Your patch doesn't apply ... I think because in v3.5 this line is
displaced by about 200 lines in the file.

patching file drivers/gpu/drm/i915/i915_gem.c
Hunk #1 FAILED at 3067.
1 out of 1 hunk FAILED -- saving rejects to file
drivers/gpu/drm/i915/i915_gem.c.rej

I got the attached to apply and it doesn't really improve the idle power
much (12.5W).

James

---

diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index 288d7b8..2f3f279 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -2869,7 +2869,7 @@ i915_gem_object_pin_to_display_plane(struct 
drm_i915_gem_object *obj,
return ret;
 
if (pipelined != obj->ring) {
-   ret = i915_gem_object_sync(obj, pipelined);
+   ret = i915_gem_object_wait_rendering(obj);
if (ret)
return ret;
}


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Massive power regression going 3.4->3.5

[Chris Wilson]

On Tue, 31 Jul 2012 11:14:17 +0100, Chris Wilson  
wrote:
> On Tue, 31 Jul 2012 10:57:10 +0100, James Bottomley  HansenPartnership.com> wrote:
> > > When did you inspect the debug files? One effect I can imagine is that
> > > if your system was previously stuck at RPn and never upclocking the GPU
> > > when X starts. The question would then be what is preventing the GPU
> > > from reaching its lowest power state again.
> > 
> > After I logged into an xfce4 session and powertop showed idle had been
> > reached.

That you are using xfce4 makes the use of semaphores for pageflips as
being the root cause even more suspect. Pageflips are only used for a
fullscreen DRI client caalling SwapBuffers, to my knowledge xfce4 does
not use DRI at all - its compositing manager is XRender based if you
happen to be using it.

Please can you try the small patch to disable the use of semaphores for
pageflips and see if the regression remains (which I judge it will...):

diff --git a/drivers/gpu/drm/i915/i915_gem.c
b/drivers/gpu/drm/i915/i915_gem.c
index 5c4657a..f301f2f 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -3067,7 +3067,7 @@ i915_gem_object_pin_to_display_plane(struct drm_i915_gem_o
return ret;

if (pipelined != obj->ring) {
-   ret = i915_gem_object_sync(obj, pipelined);
+   ret = i915_gem_object_wait_rendering(obj);
if (ret)
return ret;
}

-- 
Chris Wilson, Intel Open Source Technology Centre

Massive power regression going 3.4->3.5

[James Bottomley]

On Tue, 2012-07-31 at 16:09 +0100, James Bottomley wrote:
> On Tue, 2012-07-31 at 07:27 -0700, Keith Packard wrote:
> > James Bottomley  writes:
> > 
> > > on 3.5 killing X causes idle power to go 14W -> 5.9W
> > > on 3.4.6 killing X causes idle power to go 6.8W -> 5.7W
> > 
> > That's actually pretty good news -- you're just not getting to RC6
> > when X is running, but RC6 is otherwise working. And, yes, the GPU
> > really can suck that much power. The debug info that Chris pointed you
> > at should tell a more complete story. For comparison, on my sandybridge
> > box this morning:
> 
> Well, I don't know what it means, but I have a culprit from bisect (I
> managed to manually verify the bisection heads which would step back
> into 3.3).
> 
> 2911a35b2e4eb87ec48d03aeb11f019e51ae3c0d is the first bad commit
> commit 2911a35b2e4eb87ec48d03aeb11f019e51ae3c0d
> Author: Ben Widawsky 
> Date:   Thu Apr 5 14:47:36 2012 -0700
> 
> drm/i915: use semaphores for the display plane
> 
> I'm going to try building 3.5 with this reverted (it doesn't revert
> cleanly).

OK, I confirm that reverting this patch in 3.5 recovers a ~6.5W idle
power.

James

Massive power regression going 3.4->3.5

[Chris Wilson]

On Tue, 31 Jul 2012 16:09:44 +0100, James Bottomley  wrote:
> On Tue, 2012-07-31 at 07:27 -0700, Keith Packard wrote:
> > James Bottomley  writes:
> > 
> > > on 3.5 killing X causes idle power to go 14W -> 5.9W
> > > on 3.4.6 killing X causes idle power to go 6.8W -> 5.7W
> > 
> > That's actually pretty good news -- you're just not getting to RC6
> > when X is running, but RC6 is otherwise working. And, yes, the GPU
> > really can suck that much power. The debug info that Chris pointed you
> > at should tell a more complete story. For comparison, on my sandybridge
> > box this morning:
> 
> Well, I don't know what it means, but I have a culprit from bisect (I
> managed to manually verify the bisection heads which would step back
> into 3.3).
> 
> 2911a35b2e4eb87ec48d03aeb11f019e51ae3c0d is the first bad commit
> commit 2911a35b2e4eb87ec48d03aeb11f019e51ae3c0d
> Author: Ben Widawsky 
> Date:   Thu Apr 5 14:47:36 2012 -0700
> 
> drm/i915: use semaphores for the display plane
> 
> I'm going to try building 3.5 with this reverted (it doesn't revert
> cleanly).

The quick test would be to simply revert the
i915_gem_object_pin_to_display_plane() hunk. That would help narrow down
whether it is a side-efffect of using the semaphore to synchronize the
pageflip, or if the existing code was broken as it was moved.

Thanks,
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre

Massive power regression going 3.4->3.5

[James Bottomley]

On Tue, 2012-07-31 at 07:27 -0700, Keith Packard wrote:
> James Bottomley  writes:
> 
> > on 3.5 killing X causes idle power to go 14W -> 5.9W
> > on 3.4.6 killing X causes idle power to go 6.8W -> 5.7W
> 
> That's actually pretty good news -- you're just not getting to RC6
> when X is running, but RC6 is otherwise working. And, yes, the GPU
> really can suck that much power. The debug info that Chris pointed you
> at should tell a more complete story. For comparison, on my sandybridge
> box this morning:

Well, I don't know what it means, but I have a culprit from bisect (I
managed to manually verify the bisection heads which would step back
into 3.3).

2911a35b2e4eb87ec48d03aeb11f019e51ae3c0d is the first bad commit
commit 2911a35b2e4eb87ec48d03aeb11f019e51ae3c0d
Author: Ben Widawsky 
Date:   Thu Apr 5 14:47:36 2012 -0700

drm/i915: use semaphores for the display plane

I'm going to try building 3.5 with this reverted (it doesn't revert
cleanly).

James

Re: Massive power regression going 3.4->3.5

[Chris Wilson]

On Tue, 31 Jul 2012 11:14:17 +0100, Chris Wilson  
wrote:
> On Tue, 31 Jul 2012 10:57:10 +0100, James Bottomley 
>  wrote:
> > > When did you inspect the debug files? One effect I can imagine is that
> > > if your system was previously stuck at RPn and never upclocking the GPU
> > > when X starts. The question would then be what is preventing the GPU
> > > from reaching its lowest power state again.
> > 
> > After I logged into an xfce4 session and powertop showed idle had been
> > reached.

That you are using xfce4 makes the use of semaphores for pageflips as
being the root cause even more suspect. Pageflips are only used for a
fullscreen DRI client caalling SwapBuffers, to my knowledge xfce4 does
not use DRI at all - its compositing manager is XRender based if you
happen to be using it.

Please can you try the small patch to disable the use of semaphores for
pageflips and see if the regression remains (which I judge it will...):

diff --git a/drivers/gpu/drm/i915/i915_gem.c
b/drivers/gpu/drm/i915/i915_gem.c
index 5c4657a..f301f2f 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -3067,7 +3067,7 @@ i915_gem_object_pin_to_display_plane(struct drm_i915_gem_o
return ret;
 
if (pipelined != obj->ring) {
-   ret = i915_gem_object_sync(obj, pipelined);
+   ret = i915_gem_object_wait_rendering(obj);
if (ret)
return ret;
}

-- 
Chris Wilson, Intel Open Source Technology Centre
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Massive power regression going 3.4->3.5

[Chris Wilson]

On Tue, 31 Jul 2012 10:57:10 +0100, James Bottomley  wrote:
> > When did you inspect the debug files? One effect I can imagine is that
> > if your system was previously stuck at RPn and never upclocking the GPU
> > when X starts. The question would then be what is preventing the GPU
> > from reaching its lowest power state again.
> 
> After I logged into an xfce4 session and powertop showed idle had been
> reached.

So it looks like rc6 is functioning as the GPU is downclocked whilst
idle and the rc6 residency counter is increasing. I guess we need a new
tree to bark at.
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre

Massive power regression going 3.4->3.5

[James Bottomley]

On Tue, 2012-07-31 at 10:54 +0100, Chris Wilson wrote:
> On Tue, 31 Jul 2012 10:37:35 +0100, James Bottomley  HansenPartnership.com> wrote:
> > On Tue, 2012-07-31 at 09:28 +0100, Chris Wilson wrote:
> > > On Tue, 31 Jul 2012 09:06:42 +0100, James Bottomley  > > HansenPartnership.com> wrote:
> > > > Actually, bad news: it looks like the problem is drm:
> > > > 
> > > > on 3.5 killing X causes idle power to go 14W -> 5.9W
> > > > on 3.4.6 killing X causes idle power to go 6.8W -> 5.7W
> > > 
> > > The files that will be the most interesting to compare at first are:
> > > 
> > > /sys/kernel/debug/dri/0/i915_drpc_info
> > > /sys/kernel/debug/dri/0/i915_cur_delayinfo
> > > /sys/kernel/debug/dri/0/i915_fbc_status
> > 
> > This is for the good kernel 3.4.6
> > 
> > jejb at dabdike> cat /sys/kernel/debug/dri/0/i915_drpc_info
> > RC information accurate: yes
> > Video Turbo Mode: yes
> > HW control enabled: yes
> > SW control enabled: no
> > RC1e Enabled: no
> > RC6 Enabled: yes
> > Deep RC6 Enabled: no
> > Deepest RC6 Enabled: no
> > Current RC state: RC6
> > Core Power Down: no
> > jejb at dabdike> cat /sys/kernel/debug/dri/0/i915_cur_delayinfo
> > GT_PERF_STATUS: 0x0d29
> > RPSTAT1: 0x00040d00
> > Render p-state ratio: 13
> > Render p-state VID: 41
> > Render p-state limit: 255
> > CAGF: 650MHz
> > RP CUR UP EI: 20459us
> > RP CUR UP: 172us
> > RP PREV UP: 0us
> > RP CUR DOWN EI: 0us
> > RP CUR DOWN: 0us
> > RP PREV DOWN: 0us
> > Lowest (RPN) frequency: 650MHz
> > Nominal (RP1) frequency: 650MHz
> > Max non-overclocked (RP0) frequency: 1100MHz
> > jejb at dabdike> cat /sys/kernel/debug/dri/0/i915_fbc_status
> > FBC disabled: disabled per module param (default off)
> > 
> > And the bad kernel 3.5
> > 
> > jejb at dabdike> cat /sys/kernel/debug/dri/0/i915_drpc_info
> > RC information accurate: yes
> > Video Turbo Mode: yes
> > HW control enabled: yes
> > SW control enabled: no
> > RC1e Enabled: no
> > RC6 Enabled: yes
> > Deep RC6 Enabled: no
> > Deepest RC6 Enabled: no
> > Current RC state: RC6
> > Core Power Down: no
> > RC6 "Locked to RPn" residency since boot: 0
> > RC6 residency since boot: 97671911
> > RC6+ residency since boot: 0
> > RC6++ residency since boot: 0
> > jejb at dabdike> cat /sys/kernel/debug/dri/0/i915_cur_delayinfo
> > GT_PERF_STATUS: 0x0d29
> > RPSTAT1: 0x00048d00
> > Render p-state ratio: 13
> > Render p-state VID: 41
> > Render p-state limit: 255
> > CAGF: 650MHz
> > RP CUR UP EI: 63719us
> > RP CUR UP: 26us
> > RP PREV UP: 0us
> > RP CUR DOWN EI: 0us
> > RP CUR DOWN: 0us
> > RP PREV DOWN: 0us
> > Lowest (RPN) frequency: 650MHz
> > Nominal (RP1) frequency: 650MHz
> > Max non-overclocked (RP0) frequency: 1100MHz
> > jejb at dabdike> cat /sys/kernel/debug/dri/0/i915_fbc_status
> > FBC disabled: disabled per module param (default off)
> 
> Ok, that rules out the the easy case of rc6 being disabled or not
> functioning at all, which could easily account for 6W.
> 
> When did you inspect the debug files? One effect I can imagine is that
> if your system was previously stuck at RPn and never upclocking the GPU
> when X starts. The question would then be what is preventing the GPU
> from reaching its lowest power state again.

After I logged into an xfce4 session and powertop showed idle had been
reached.

James

Massive power regression going 3.4->3.5

[Chris Wilson]

On Tue, 31 Jul 2012 10:37:35 +0100, James Bottomley  wrote:
> On Tue, 2012-07-31 at 09:28 +0100, Chris Wilson wrote:
> > On Tue, 31 Jul 2012 09:06:42 +0100, James Bottomley  > HansenPartnership.com> wrote:
> > > Actually, bad news: it looks like the problem is drm:
> > > 
> > > on 3.5 killing X causes idle power to go 14W -> 5.9W
> > > on 3.4.6 killing X causes idle power to go 6.8W -> 5.7W
> > 
> > The files that will be the most interesting to compare at first are:
> > 
> > /sys/kernel/debug/dri/0/i915_drpc_info
> > /sys/kernel/debug/dri/0/i915_cur_delayinfo
> > /sys/kernel/debug/dri/0/i915_fbc_status
> 
> This is for the good kernel 3.4.6
> 
> jejb at dabdike> cat /sys/kernel/debug/dri/0/i915_drpc_info
> RC information accurate: yes
> Video Turbo Mode: yes
> HW control enabled: yes
> SW control enabled: no
> RC1e Enabled: no
> RC6 Enabled: yes
> Deep RC6 Enabled: no
> Deepest RC6 Enabled: no
> Current RC state: RC6
> Core Power Down: no
> jejb at dabdike> cat /sys/kernel/debug/dri/0/i915_cur_delayinfo
> GT_PERF_STATUS: 0x0d29
> RPSTAT1: 0x00040d00
> Render p-state ratio: 13
> Render p-state VID: 41
> Render p-state limit: 255
> CAGF: 650MHz
> RP CUR UP EI: 20459us
> RP CUR UP: 172us
> RP PREV UP: 0us
> RP CUR DOWN EI: 0us
> RP CUR DOWN: 0us
> RP PREV DOWN: 0us
> Lowest (RPN) frequency: 650MHz
> Nominal (RP1) frequency: 650MHz
> Max non-overclocked (RP0) frequency: 1100MHz
> jejb at dabdike> cat /sys/kernel/debug/dri/0/i915_fbc_status
> FBC disabled: disabled per module param (default off)
> 
> And the bad kernel 3.5
> 
> jejb at dabdike> cat /sys/kernel/debug/dri/0/i915_drpc_info
> RC information accurate: yes
> Video Turbo Mode: yes
> HW control enabled: yes
> SW control enabled: no
> RC1e Enabled: no
> RC6 Enabled: yes
> Deep RC6 Enabled: no
> Deepest RC6 Enabled: no
> Current RC state: RC6
> Core Power Down: no
> RC6 "Locked to RPn" residency since boot: 0
> RC6 residency since boot: 97671911
> RC6+ residency since boot: 0
> RC6++ residency since boot: 0
> jejb at dabdike> cat /sys/kernel/debug/dri/0/i915_cur_delayinfo
> GT_PERF_STATUS: 0x0d29
> RPSTAT1: 0x00048d00
> Render p-state ratio: 13
> Render p-state VID: 41
> Render p-state limit: 255
> CAGF: 650MHz
> RP CUR UP EI: 63719us
> RP CUR UP: 26us
> RP PREV UP: 0us
> RP CUR DOWN EI: 0us
> RP CUR DOWN: 0us
> RP PREV DOWN: 0us
> Lowest (RPN) frequency: 650MHz
> Nominal (RP1) frequency: 650MHz
> Max non-overclocked (RP0) frequency: 1100MHz
> jejb at dabdike> cat /sys/kernel/debug/dri/0/i915_fbc_status
> FBC disabled: disabled per module param (default off)

Ok, that rules out the the easy case of rc6 being disabled or not
functioning at all, which could easily account for 6W.

When did you inspect the debug files? One effect I can imagine is that
if your system was previously stuck at RPn and never upclocking the GPU
when X starts. The question would then be what is preventing the GPU
from reaching its lowest power state again.
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre

Massive power regression going 3.4->3.5

[James Bottomley]

On Tue, 2012-07-31 at 09:28 +0100, Chris Wilson wrote:
> On Tue, 31 Jul 2012 09:06:42 +0100, James Bottomley  HansenPartnership.com> wrote:
> > Actually, bad news: it looks like the problem is drm:
> > 
> > on 3.5 killing X causes idle power to go 14W -> 5.9W
> > on 3.4.6 killing X causes idle power to go 6.8W -> 5.7W
> 
> The files that will be the most interesting to compare at first are:
> 
> /sys/kernel/debug/dri/0/i915_drpc_info
> /sys/kernel/debug/dri/0/i915_cur_delayinfo
> /sys/kernel/debug/dri/0/i915_fbc_status

This is for the good kernel 3.4.6

jejb at dabdike> cat /sys/kernel/debug/dri/0/i915_drpc_info
RC information accurate: yes
Video Turbo Mode: yes
HW control enabled: yes
SW control enabled: no
RC1e Enabled: no
RC6 Enabled: yes
Deep RC6 Enabled: no
Deepest RC6 Enabled: no
Current RC state: RC6
Core Power Down: no
jejb at dabdike> cat /sys/kernel/debug/dri/0/i915_cur_delayinfo
GT_PERF_STATUS: 0x0d29
RPSTAT1: 0x00040d00
Render p-state ratio: 13
Render p-state VID: 41
Render p-state limit: 255
CAGF: 650MHz
RP CUR UP EI: 20459us
RP CUR UP: 172us
RP PREV UP: 0us
RP CUR DOWN EI: 0us
RP CUR DOWN: 0us
RP PREV DOWN: 0us
Lowest (RPN) frequency: 650MHz
Nominal (RP1) frequency: 650MHz
Max non-overclocked (RP0) frequency: 1100MHz
jejb at dabdike> cat /sys/kernel/debug/dri/0/i915_fbc_status
FBC disabled: disabled per module param (default off)

And the bad kernel 3.5

jejb at dabdike> cat /sys/kernel/debug/dri/0/i915_drpc_info
RC information accurate: yes
Video Turbo Mode: yes
HW control enabled: yes
SW control enabled: no
RC1e Enabled: no
RC6 Enabled: yes
Deep RC6 Enabled: no
Deepest RC6 Enabled: no
Current RC state: RC6
Core Power Down: no
RC6 "Locked to RPn" residency since boot: 0
RC6 residency since boot: 97671911
RC6+ residency since boot: 0
RC6++ residency since boot: 0
jejb at dabdike> cat /sys/kernel/debug/dri/0/i915_cur_delayinfo
GT_PERF_STATUS: 0x0d29
RPSTAT1: 0x00048d00
Render p-state ratio: 13
Render p-state VID: 41
Render p-state limit: 255
CAGF: 650MHz
RP CUR UP EI: 63719us
RP CUR UP: 26us
RP PREV UP: 0us
RP CUR DOWN EI: 0us
RP CUR DOWN: 0us
RP PREV DOWN: 0us
Lowest (RPN) frequency: 650MHz
Nominal (RP1) frequency: 650MHz
Max non-overclocked (RP0) frequency: 1100MHz
jejb at dabdike> cat /sys/kernel/debug/dri/0/i915_fbc_status
FBC disabled: disabled per module param (default off)


> However if it was simple regression in drm, then the bisect would have
> continued to work despite the merge point jumping between 3.4 and 3.5,
> right?

No ... the bisect stepped back into 3.3 which mean I lost the ability to
detect the regression.  I think it might be fixable given I have a more
precise identifier for the tree because it looks like none of the roots
of the drm tree is before 3.4-rc.

James

Massive power regression going 3.4->3.5

[Chris Wilson]

On Tue, 31 Jul 2012 09:06:42 +0100, James Bottomley  wrote:
> Actually, bad news: it looks like the problem is drm:
> 
> on 3.5 killing X causes idle power to go 14W -> 5.9W
> on 3.4.6 killing X causes idle power to go 6.8W -> 5.7W

The files that will be the most interesting to compare at first are:

/sys/kernel/debug/dri/0/i915_drpc_info
/sys/kernel/debug/dri/0/i915_cur_delayinfo
/sys/kernel/debug/dri/0/i915_fbc_status

However if it was simple regression in drm, then the bisect would have
continued to work despite the merge point jumping between 3.4 and 3.5,
right?

Thanks,
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre

Re: Massive power regression going 3.4->3.5

[James Bottomley]

On Tue, 2012-07-31 at 16:09 +0100, James Bottomley wrote:
> On Tue, 2012-07-31 at 07:27 -0700, Keith Packard wrote:
> > James Bottomley  writes:
> > 
> > > on 3.5 killing X causes idle power to go 14W -> 5.9W
> > > on 3.4.6 killing X causes idle power to go 6.8W -> 5.7W
> > 
> > That's actually pretty good news -- you're just not getting to RC6
> > when X is running, but RC6 is otherwise working. And, yes, the GPU
> > really can suck that much power. The debug info that Chris pointed you
> > at should tell a more complete story. For comparison, on my sandybridge
> > box this morning:
> 
> Well, I don't know what it means, but I have a culprit from bisect (I
> managed to manually verify the bisection heads which would step back
> into 3.3).
> 
> 2911a35b2e4eb87ec48d03aeb11f019e51ae3c0d is the first bad commit
> commit 2911a35b2e4eb87ec48d03aeb11f019e51ae3c0d
> Author: Ben Widawsky 
> Date:   Thu Apr 5 14:47:36 2012 -0700
> 
> drm/i915: use semaphores for the display plane
> 
> I'm going to try building 3.5 with this reverted (it doesn't revert
> cleanly).

OK, I confirm that reverting this patch in 3.5 recovers a ~6.5W idle
power.

James


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Massive power regression going 3.4->3.5

[James Bottomley]

On Tue, 2012-07-31 at 08:31 +0100, James Bottomley wrote:
> On Mon, 2012-07-30 at 11:23 -0700, Keith Packard wrote:
> > James Bottomley  writes:
> > 
> > > On Mon, 2012-07-30 at 09:33 -0700, Keith Packard wrote:
> > >> James Bottomley  writes:
> > >> 
> > >> > OK, I've run the bisect as far as I can.  It looks to be in the drm
> > >> > tree.  Unfortunately, this tree has several merge points, some of which
> > >> > go further back than v3.4.  Unfortunately, once the bisect steps back
> > >> > before 3.4, we lose the changes that gave us the power savings, making
> > >> > further debugging impossible
> > >> 
> > >> What machine is this on? There are a few 'disable some power savings'
> > >> patches in that list to work around issues on various machines; knowing
> > >> what machine you're using can isolate which ones might have had some
> > >> effect on power usage...
> > >
> > > Lenovo X220i
> > 
> > I don't see a whole lot of context from the elided email bits you'd sent
> > previously; can you summarize the issue in terms of how much power
> > savings you're losing, how you're measuring it and what's going on in
> > the system when the power savings is different?
> 
> Sure.  Going from 3.3->3.4 we saw massive increase in power savings due
> to various autosuspend updates.  The idle power consumption of the X220i
> went from about 13W to 6.5W.  In 3.5 this seems to be reversed, with the
> idle power consumption back up to around 14W.  I can't quite believe the
> graphics chip is responsible for around 7W, so it looks like it's some
> interaction between graphics and other subsystems.
> 
> > Have you tried measuring power with X not running? How about with
> > compositing and other desktop effects disabled? 
> 
> Sure, I can try doing that ... but remember this is a system where the
> drm is used for the console as well.

Actually, bad news: it looks like the problem is drm:

on 3.5 killing X causes idle power to go 14W -> 5.9W
on 3.4.6 killing X causes idle power to go 6.8W -> 5.7W

James

Re: Massive power regression going 3.4->3.5

[Chris Wilson]

On Tue, 31 Jul 2012 16:09:44 +0100, James Bottomley 
 wrote:
> On Tue, 2012-07-31 at 07:27 -0700, Keith Packard wrote:
> > James Bottomley  writes:
> > 
> > > on 3.5 killing X causes idle power to go 14W -> 5.9W
> > > on 3.4.6 killing X causes idle power to go 6.8W -> 5.7W
> > 
> > That's actually pretty good news -- you're just not getting to RC6
> > when X is running, but RC6 is otherwise working. And, yes, the GPU
> > really can suck that much power. The debug info that Chris pointed you
> > at should tell a more complete story. For comparison, on my sandybridge
> > box this morning:
> 
> Well, I don't know what it means, but I have a culprit from bisect (I
> managed to manually verify the bisection heads which would step back
> into 3.3).
> 
> 2911a35b2e4eb87ec48d03aeb11f019e51ae3c0d is the first bad commit
> commit 2911a35b2e4eb87ec48d03aeb11f019e51ae3c0d
> Author: Ben Widawsky 
> Date:   Thu Apr 5 14:47:36 2012 -0700
> 
> drm/i915: use semaphores for the display plane
> 
> I'm going to try building 3.5 with this reverted (it doesn't revert
> cleanly).

The quick test would be to simply revert the
i915_gem_object_pin_to_display_plane() hunk. That would help narrow down
whether it is a side-efffect of using the semaphore to synchronize the
pageflip, or if the existing code was broken as it was moved.

Thanks,
-Chris

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Massive power regression going 3.4->3.5

[James Bottomley]

On Mon, 2012-07-30 at 11:23 -0700, Keith Packard wrote:
> James Bottomley  writes:
> 
> > On Mon, 2012-07-30 at 09:33 -0700, Keith Packard wrote:
> >> James Bottomley  writes:
> >> 
> >> > OK, I've run the bisect as far as I can.  It looks to be in the drm
> >> > tree.  Unfortunately, this tree has several merge points, some of which
> >> > go further back than v3.4.  Unfortunately, once the bisect steps back
> >> > before 3.4, we lose the changes that gave us the power savings, making
> >> > further debugging impossible
> >> 
> >> What machine is this on? There are a few 'disable some power savings'
> >> patches in that list to work around issues on various machines; knowing
> >> what machine you're using can isolate which ones might have had some
> >> effect on power usage...
> >
> > Lenovo X220i
> 
> I don't see a whole lot of context from the elided email bits you'd sent
> previously; can you summarize the issue in terms of how much power
> savings you're losing, how you're measuring it and what's going on in
> the system when the power savings is different?

Sure.  Going from 3.3->3.4 we saw massive increase in power savings due
to various autosuspend updates.  The idle power consumption of the X220i
went from about 13W to 6.5W.  In 3.5 this seems to be reversed, with the
idle power consumption back up to around 14W.  I can't quite believe the
graphics chip is responsible for around 7W, so it looks like it's some
interaction between graphics and other subsystems.

> Have you tried measuring power with X not running? How about with
> compositing and other desktop effects disabled? 

Sure, I can try doing that ... but remember this is a system where the
drm is used for the console as well.

James

Re: Massive power regression going 3.4->3.5

[James Bottomley]

On Tue, 2012-07-31 at 07:27 -0700, Keith Packard wrote:
> James Bottomley  writes:
> 
> > on 3.5 killing X causes idle power to go 14W -> 5.9W
> > on 3.4.6 killing X causes idle power to go 6.8W -> 5.7W
> 
> That's actually pretty good news -- you're just not getting to RC6
> when X is running, but RC6 is otherwise working. And, yes, the GPU
> really can suck that much power. The debug info that Chris pointed you
> at should tell a more complete story. For comparison, on my sandybridge
> box this morning:

Well, I don't know what it means, but I have a culprit from bisect (I
managed to manually verify the bisection heads which would step back
into 3.3).

2911a35b2e4eb87ec48d03aeb11f019e51ae3c0d is the first bad commit
commit 2911a35b2e4eb87ec48d03aeb11f019e51ae3c0d
Author: Ben Widawsky 
Date:   Thu Apr 5 14:47:36 2012 -0700

drm/i915: use semaphores for the display plane

I'm going to try building 3.5 with this reverted (it doesn't revert
cleanly).

James


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Re: Massive power regression going 3.4->3.5

[Keith Packard]

James Bottomley  writes:

> on 3.5 killing X causes idle power to go 14W -> 5.9W
> on 3.4.6 killing X causes idle power to go 6.8W -> 5.7W

That's actually pretty good news -- you're just not getting to RC6
when X is running, but RC6 is otherwise working. And, yes, the GPU
really can suck that much power. The debug info that Chris pointed you
at should tell a more complete story. For comparison, on my sandybridge
box this morning:

::
i915_drpc_info
::
RC information accurate: yes
Video Turbo Mode: yes
HW control enabled: yes
SW control enabled: no
RC1e Enabled: no
RC6 Enabled: yes
Deep RC6 Enabled: no
Deepest RC6 Enabled: no
Current RC state: RC6
Core Power Down: no
RC6 "Locked to RPn" residency since boot: 0
RC6 residency since boot: 898339862
RC6+ residency since boot: 0
RC6++ residency since boot: 0
::
i915_cur_delayinfo
::
GT_PERF_STATUS: 0x0729
RPSTAT1: 0x00048700
Render p-state ratio: 7
Render p-state VID: 41
Render p-state limit: 24
CAGF: 350MHz
RP CUR UP EI: 54631us
RP CUR UP: 136us
RP PREV UP: 0us
RP CUR DOWN EI: 0us
RP CUR DOWN: 0us
RP PREV DOWN: 0us
Lowest (RPN) frequency: 350MHz
Nominal (RP1) frequency: 350MHz
Max non-overclocked (RP0) frequency: 1200MHz
::
i915_fbc_status
::
FBC disabled: multiple pipes are enabled

-- 
keith.pack...@intel.com


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Massive power regression going 3.4->3.5

[Keith Packard]

James Bottomley  writes:

> on 3.5 killing X causes idle power to go 14W -> 5.9W
> on 3.4.6 killing X causes idle power to go 6.8W -> 5.7W

That's actually pretty good news -- you're just not getting to RC6
when X is running, but RC6 is otherwise working. And, yes, the GPU
really can suck that much power. The debug info that Chris pointed you
at should tell a more complete story. For comparison, on my sandybridge
box this morning:

::
i915_drpc_info
::
RC information accurate: yes
Video Turbo Mode: yes
HW control enabled: yes
SW control enabled: no
RC1e Enabled: no
RC6 Enabled: yes
Deep RC6 Enabled: no
Deepest RC6 Enabled: no
Current RC state: RC6
Core Power Down: no
RC6 "Locked to RPn" residency since boot: 0
RC6 residency since boot: 898339862
RC6+ residency since boot: 0
RC6++ residency since boot: 0
::
i915_cur_delayinfo
::
GT_PERF_STATUS: 0x0729
RPSTAT1: 0x00048700
Render p-state ratio: 7
Render p-state VID: 41
Render p-state limit: 24
CAGF: 350MHz
RP CUR UP EI: 54631us
RP CUR UP: 136us
RP PREV UP: 0us
RP CUR DOWN EI: 0us
RP CUR DOWN: 0us
RP PREV DOWN: 0us
Lowest (RPN) frequency: 350MHz
Nominal (RP1) frequency: 350MHz
Max non-overclocked (RP0) frequency: 1200MHz
::
i915_fbc_status
::
FBC disabled: multiple pipes are enabled

-- 
keith.packard at intel.com
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Re: Massive power regression going 3.4->3.5

[Chris Wilson]

On Tue, 31 Jul 2012 10:57:10 +0100, James Bottomley 
 wrote:
> > When did you inspect the debug files? One effect I can imagine is that
> > if your system was previously stuck at RPn and never upclocking the GPU
> > when X starts. The question would then be what is preventing the GPU
> > from reaching its lowest power state again.
> 
> After I logged into an xfce4 session and powertop showed idle had been
> reached.

So it looks like rc6 is functioning as the GPU is downclocked whilst
idle and the rc6 residency counter is increasing. I guess we need a new
tree to bark at.
-Chris

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Re: Massive power regression going 3.4->3.5

[James Bottomley]

On Tue, 2012-07-31 at 10:54 +0100, Chris Wilson wrote:
> On Tue, 31 Jul 2012 10:37:35 +0100, James Bottomley 
>  wrote:
> > On Tue, 2012-07-31 at 09:28 +0100, Chris Wilson wrote:
> > > On Tue, 31 Jul 2012 09:06:42 +0100, James Bottomley 
> > >  wrote:
> > > > Actually, bad news: it looks like the problem is drm:
> > > > 
> > > > on 3.5 killing X causes idle power to go 14W -> 5.9W
> > > > on 3.4.6 killing X causes idle power to go 6.8W -> 5.7W
> > > 
> > > The files that will be the most interesting to compare at first are:
> > > 
> > > /sys/kernel/debug/dri/0/i915_drpc_info
> > > /sys/kernel/debug/dri/0/i915_cur_delayinfo
> > > /sys/kernel/debug/dri/0/i915_fbc_status
> > 
> > This is for the good kernel 3.4.6
> > 
> > jejb@dabdike> cat /sys/kernel/debug/dri/0/i915_drpc_info
> > RC information accurate: yes
> > Video Turbo Mode: yes
> > HW control enabled: yes
> > SW control enabled: no
> > RC1e Enabled: no
> > RC6 Enabled: yes
> > Deep RC6 Enabled: no
> > Deepest RC6 Enabled: no
> > Current RC state: RC6
> > Core Power Down: no
> > jejb@dabdike> cat /sys/kernel/debug/dri/0/i915_cur_delayinfo
> > GT_PERF_STATUS: 0x0d29
> > RPSTAT1: 0x00040d00
> > Render p-state ratio: 13
> > Render p-state VID: 41
> > Render p-state limit: 255
> > CAGF: 650MHz
> > RP CUR UP EI: 20459us
> > RP CUR UP: 172us
> > RP PREV UP: 0us
> > RP CUR DOWN EI: 0us
> > RP CUR DOWN: 0us
> > RP PREV DOWN: 0us
> > Lowest (RPN) frequency: 650MHz
> > Nominal (RP1) frequency: 650MHz
> > Max non-overclocked (RP0) frequency: 1100MHz
> > jejb@dabdike> cat /sys/kernel/debug/dri/0/i915_fbc_status
> > FBC disabled: disabled per module param (default off)
> > 
> > And the bad kernel 3.5
> > 
> > jejb@dabdike> cat /sys/kernel/debug/dri/0/i915_drpc_info
> > RC information accurate: yes
> > Video Turbo Mode: yes
> > HW control enabled: yes
> > SW control enabled: no
> > RC1e Enabled: no
> > RC6 Enabled: yes
> > Deep RC6 Enabled: no
> > Deepest RC6 Enabled: no
> > Current RC state: RC6
> > Core Power Down: no
> > RC6 "Locked to RPn" residency since boot: 0
> > RC6 residency since boot: 97671911
> > RC6+ residency since boot: 0
> > RC6++ residency since boot: 0
> > jejb@dabdike> cat /sys/kernel/debug/dri/0/i915_cur_delayinfo
> > GT_PERF_STATUS: 0x0d29
> > RPSTAT1: 0x00048d00
> > Render p-state ratio: 13
> > Render p-state VID: 41
> > Render p-state limit: 255
> > CAGF: 650MHz
> > RP CUR UP EI: 63719us
> > RP CUR UP: 26us
> > RP PREV UP: 0us
> > RP CUR DOWN EI: 0us
> > RP CUR DOWN: 0us
> > RP PREV DOWN: 0us
> > Lowest (RPN) frequency: 650MHz
> > Nominal (RP1) frequency: 650MHz
> > Max non-overclocked (RP0) frequency: 1100MHz
> > jejb@dabdike> cat /sys/kernel/debug/dri/0/i915_fbc_status
> > FBC disabled: disabled per module param (default off)
> 
> Ok, that rules out the the easy case of rc6 being disabled or not
> functioning at all, which could easily account for 6W.
> 
> When did you inspect the debug files? One effect I can imagine is that
> if your system was previously stuck at RPn and never upclocking the GPU
> when X starts. The question would then be what is preventing the GPU
> from reaching its lowest power state again.

After I logged into an xfce4 session and powertop showed idle had been
reached.

James


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Re: Massive power regression going 3.4->3.5

[Chris Wilson]

On Tue, 31 Jul 2012 10:37:35 +0100, James Bottomley 
 wrote:
> On Tue, 2012-07-31 at 09:28 +0100, Chris Wilson wrote:
> > On Tue, 31 Jul 2012 09:06:42 +0100, James Bottomley 
> >  wrote:
> > > Actually, bad news: it looks like the problem is drm:
> > > 
> > > on 3.5 killing X causes idle power to go 14W -> 5.9W
> > > on 3.4.6 killing X causes idle power to go 6.8W -> 5.7W
> > 
> > The files that will be the most interesting to compare at first are:
> > 
> > /sys/kernel/debug/dri/0/i915_drpc_info
> > /sys/kernel/debug/dri/0/i915_cur_delayinfo
> > /sys/kernel/debug/dri/0/i915_fbc_status
> 
> This is for the good kernel 3.4.6
> 
> jejb@dabdike> cat /sys/kernel/debug/dri/0/i915_drpc_info
> RC information accurate: yes
> Video Turbo Mode: yes
> HW control enabled: yes
> SW control enabled: no
> RC1e Enabled: no
> RC6 Enabled: yes
> Deep RC6 Enabled: no
> Deepest RC6 Enabled: no
> Current RC state: RC6
> Core Power Down: no
> jejb@dabdike> cat /sys/kernel/debug/dri/0/i915_cur_delayinfo
> GT_PERF_STATUS: 0x0d29
> RPSTAT1: 0x00040d00
> Render p-state ratio: 13
> Render p-state VID: 41
> Render p-state limit: 255
> CAGF: 650MHz
> RP CUR UP EI: 20459us
> RP CUR UP: 172us
> RP PREV UP: 0us
> RP CUR DOWN EI: 0us
> RP CUR DOWN: 0us
> RP PREV DOWN: 0us
> Lowest (RPN) frequency: 650MHz
> Nominal (RP1) frequency: 650MHz
> Max non-overclocked (RP0) frequency: 1100MHz
> jejb@dabdike> cat /sys/kernel/debug/dri/0/i915_fbc_status
> FBC disabled: disabled per module param (default off)
> 
> And the bad kernel 3.5
> 
> jejb@dabdike> cat /sys/kernel/debug/dri/0/i915_drpc_info
> RC information accurate: yes
> Video Turbo Mode: yes
> HW control enabled: yes
> SW control enabled: no
> RC1e Enabled: no
> RC6 Enabled: yes
> Deep RC6 Enabled: no
> Deepest RC6 Enabled: no
> Current RC state: RC6
> Core Power Down: no
> RC6 "Locked to RPn" residency since boot: 0
> RC6 residency since boot: 97671911
> RC6+ residency since boot: 0
> RC6++ residency since boot: 0
> jejb@dabdike> cat /sys/kernel/debug/dri/0/i915_cur_delayinfo
> GT_PERF_STATUS: 0x0d29
> RPSTAT1: 0x00048d00
> Render p-state ratio: 13
> Render p-state VID: 41
> Render p-state limit: 255
> CAGF: 650MHz
> RP CUR UP EI: 63719us
> RP CUR UP: 26us
> RP PREV UP: 0us
> RP CUR DOWN EI: 0us
> RP CUR DOWN: 0us
> RP PREV DOWN: 0us
> Lowest (RPN) frequency: 650MHz
> Nominal (RP1) frequency: 650MHz
> Max non-overclocked (RP0) frequency: 1100MHz
> jejb@dabdike> cat /sys/kernel/debug/dri/0/i915_fbc_status
> FBC disabled: disabled per module param (default off)

Ok, that rules out the the easy case of rc6 being disabled or not
functioning at all, which could easily account for 6W.

When did you inspect the debug files? One effect I can imagine is that
if your system was previously stuck at RPn and never upclocking the GPU
when X starts. The question would then be what is preventing the GPU
from reaching its lowest power state again.
-Chris

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Re: Massive power regression going 3.4->3.5

[James Bottomley]

On Tue, 2012-07-31 at 09:28 +0100, Chris Wilson wrote:
> On Tue, 31 Jul 2012 09:06:42 +0100, James Bottomley 
>  wrote:
> > Actually, bad news: it looks like the problem is drm:
> > 
> > on 3.5 killing X causes idle power to go 14W -> 5.9W
> > on 3.4.6 killing X causes idle power to go 6.8W -> 5.7W
> 
> The files that will be the most interesting to compare at first are:
> 
> /sys/kernel/debug/dri/0/i915_drpc_info
> /sys/kernel/debug/dri/0/i915_cur_delayinfo
> /sys/kernel/debug/dri/0/i915_fbc_status

This is for the good kernel 3.4.6

jejb@dabdike> cat /sys/kernel/debug/dri/0/i915_drpc_info
RC information accurate: yes
Video Turbo Mode: yes
HW control enabled: yes
SW control enabled: no
RC1e Enabled: no
RC6 Enabled: yes
Deep RC6 Enabled: no
Deepest RC6 Enabled: no
Current RC state: RC6
Core Power Down: no
jejb@dabdike> cat /sys/kernel/debug/dri/0/i915_cur_delayinfo
GT_PERF_STATUS: 0x0d29
RPSTAT1: 0x00040d00
Render p-state ratio: 13
Render p-state VID: 41
Render p-state limit: 255
CAGF: 650MHz
RP CUR UP EI: 20459us
RP CUR UP: 172us
RP PREV UP: 0us
RP CUR DOWN EI: 0us
RP CUR DOWN: 0us
RP PREV DOWN: 0us
Lowest (RPN) frequency: 650MHz
Nominal (RP1) frequency: 650MHz
Max non-overclocked (RP0) frequency: 1100MHz
jejb@dabdike> cat /sys/kernel/debug/dri/0/i915_fbc_status
FBC disabled: disabled per module param (default off)

And the bad kernel 3.5

jejb@dabdike> cat /sys/kernel/debug/dri/0/i915_drpc_info
RC information accurate: yes
Video Turbo Mode: yes
HW control enabled: yes
SW control enabled: no
RC1e Enabled: no
RC6 Enabled: yes
Deep RC6 Enabled: no
Deepest RC6 Enabled: no
Current RC state: RC6
Core Power Down: no
RC6 "Locked to RPn" residency since boot: 0
RC6 residency since boot: 97671911
RC6+ residency since boot: 0
RC6++ residency since boot: 0
jejb@dabdike> cat /sys/kernel/debug/dri/0/i915_cur_delayinfo
GT_PERF_STATUS: 0x0d29
RPSTAT1: 0x00048d00
Render p-state ratio: 13
Render p-state VID: 41
Render p-state limit: 255
CAGF: 650MHz
RP CUR UP EI: 63719us
RP CUR UP: 26us
RP PREV UP: 0us
RP CUR DOWN EI: 0us
RP CUR DOWN: 0us
RP PREV DOWN: 0us
Lowest (RPN) frequency: 650MHz
Nominal (RP1) frequency: 650MHz
Max non-overclocked (RP0) frequency: 1100MHz
jejb@dabdike> cat /sys/kernel/debug/dri/0/i915_fbc_status
FBC disabled: disabled per module param (default off)


> However if it was simple regression in drm, then the bisect would have
> continued to work despite the merge point jumping between 3.4 and 3.5,
> right?

No ... the bisect stepped back into 3.3 which mean I lost the ability to
detect the regression.  I think it might be fixable given I have a more
precise identifier for the tree because it looks like none of the roots
of the drm tree is before 3.4-rc.

James


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Re: Massive power regression going 3.4->3.5

[Chris Wilson]

On Tue, 31 Jul 2012 09:06:42 +0100, James Bottomley 
 wrote:
> Actually, bad news: it looks like the problem is drm:
> 
> on 3.5 killing X causes idle power to go 14W -> 5.9W
> on 3.4.6 killing X causes idle power to go 6.8W -> 5.7W

The files that will be the most interesting to compare at first are:

/sys/kernel/debug/dri/0/i915_drpc_info
/sys/kernel/debug/dri/0/i915_cur_delayinfo
/sys/kernel/debug/dri/0/i915_fbc_status

However if it was simple regression in drm, then the bisect would have
continued to work despite the merge point jumping between 3.4 and 3.5,
right?

Thanks,
-Chris

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Re: Massive power regression going 3.4->3.5

[James Bottomley]

On Tue, 2012-07-31 at 08:31 +0100, James Bottomley wrote:
> On Mon, 2012-07-30 at 11:23 -0700, Keith Packard wrote:
> > James Bottomley  writes:
> > 
> > > On Mon, 2012-07-30 at 09:33 -0700, Keith Packard wrote:
> > >> James Bottomley  writes:
> > >> 
> > >> > OK, I've run the bisect as far as I can.  It looks to be in the drm
> > >> > tree.  Unfortunately, this tree has several merge points, some of which
> > >> > go further back than v3.4.  Unfortunately, once the bisect steps back
> > >> > before 3.4, we lose the changes that gave us the power savings, making
> > >> > further debugging impossible
> > >> 
> > >> What machine is this on? There are a few 'disable some power savings'
> > >> patches in that list to work around issues on various machines; knowing
> > >> what machine you're using can isolate which ones might have had some
> > >> effect on power usage...
> > >
> > > Lenovo X220i
> > 
> > I don't see a whole lot of context from the elided email bits you'd sent
> > previously; can you summarize the issue in terms of how much power
> > savings you're losing, how you're measuring it and what's going on in
> > the system when the power savings is different?
> 
> Sure.  Going from 3.3->3.4 we saw massive increase in power savings due
> to various autosuspend updates.  The idle power consumption of the X220i
> went from about 13W to 6.5W.  In 3.5 this seems to be reversed, with the
> idle power consumption back up to around 14W.  I can't quite believe the
> graphics chip is responsible for around 7W, so it looks like it's some
> interaction between graphics and other subsystems.
> 
> > Have you tried measuring power with X not running? How about with
> > compositing and other desktop effects disabled? 
> 
> Sure, I can try doing that ... but remember this is a system where the
> drm is used for the console as well.

Actually, bad news: it looks like the problem is drm:

on 3.5 killing X causes idle power to go 14W -> 5.9W
on 3.4.6 killing X causes idle power to go 6.8W -> 5.7W

James


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Re: Massive power regression going 3.4->3.5

[James Bottomley]

On Mon, 2012-07-30 at 11:23 -0700, Keith Packard wrote:
> James Bottomley  writes:
> 
> > On Mon, 2012-07-30 at 09:33 -0700, Keith Packard wrote:
> >> James Bottomley  writes:
> >> 
> >> > OK, I've run the bisect as far as I can.  It looks to be in the drm
> >> > tree.  Unfortunately, this tree has several merge points, some of which
> >> > go further back than v3.4.  Unfortunately, once the bisect steps back
> >> > before 3.4, we lose the changes that gave us the power savings, making
> >> > further debugging impossible
> >> 
> >> What machine is this on? There are a few 'disable some power savings'
> >> patches in that list to work around issues on various machines; knowing
> >> what machine you're using can isolate which ones might have had some
> >> effect on power usage...
> >
> > Lenovo X220i
> 
> I don't see a whole lot of context from the elided email bits you'd sent
> previously; can you summarize the issue in terms of how much power
> savings you're losing, how you're measuring it and what's going on in
> the system when the power savings is different?

Sure.  Going from 3.3->3.4 we saw massive increase in power savings due
to various autosuspend updates.  The idle power consumption of the X220i
went from about 13W to 6.5W.  In 3.5 this seems to be reversed, with the
idle power consumption back up to around 14W.  I can't quite believe the
graphics chip is responsible for around 7W, so it looks like it's some
interaction between graphics and other subsystems.

> Have you tried measuring power with X not running? How about with
> compositing and other desktop effects disabled? 

Sure, I can try doing that ... but remember this is a system where the
drm is used for the console as well.

James


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Massive power regression going 3.4->3.5

[James Bottomley]

On Mon, 2012-07-30 at 09:33 -0700, Keith Packard wrote:
> James Bottomley  writes:
> 
> > OK, I've run the bisect as far as I can.  It looks to be in the drm
> > tree.  Unfortunately, this tree has several merge points, some of which
> > go further back than v3.4.  Unfortunately, once the bisect steps back
> > before 3.4, we lose the changes that gave us the power savings, making
> > further debugging impossible
> 
> What machine is this on? There are a few 'disable some power savings'
> patches in that list to work around issues on various machines; knowing
> what machine you're using can isolate which ones might have had some
> effect on power usage...

Lenovo X220i

The display device is

00:02.0 VGA compatible controller: Intel Corporation
82845G/GL[Brookdale-G]/GE Chipset Integrated Graphics Device (rev 03)
(prog-if 00 [VGA controller])
Subsystem: Giga-byte Technology Device 2562
Flags: bus master, fast devsel, latency 0, IRQ 16
Memory at e000 (32-bit, prefetchable) [size=128M]
Memory at e820 (32-bit, non-prefetchable) [size=512K]
Expansion ROM at  [disabled]
Capabilities: 
Kernel driver in use: i915


James

Massive power regression going 3.4->3.5

[James Bottomley]

On Mon, 2012-07-30 at 10:46 +0100, James Bottomley wrote:
> On Sun, 2012-07-29 at 21:25 +0200, Rafael J. Wysocki wrote:
> > On Sunday, July 29, 2012, Rafael J. Wysocki wrote:
> > > On Sunday, July 29, 2012, James Bottomley wrote:
> > > > On Sat, 2012-07-28 at 22:29 +0200, Rafael J. Wysocki wrote:
> > > > > On Saturday, July 28, 2012, Rafael J. Wysocki wrote:
> > > > > > On Saturday, July 28, 2012, James Bottomley wrote:
> > > > > > > One of the great things about the 3.4 kernel was the massive 
> > > > > > > increase in
> > > > > > > power savings on my x220i laptop.  With full PCI suspend, it 
> > > > > > > could get
> > > > > > > down to 6.5W in idle with a dim screen, provided I used powertop 
> > > > > > > 2.0 to
> > > > > > > activate all the tunings).  I just upgraded to 3.5 (the openSUSE
> > > > > > > tumbleweed kernel) and all the power savings are gone.  Now it's 
> > > > > > > back to
> > > > > > > its previous behaviour of idle somewhere between 16-18W.
> > > > > > 
> > > > > > Please check dbe9a2e (ACPI / PM: Make acpi_pm_device_sleep_state() 
> > > > > > follow the
> > > > > > specification) for starters.
> > > > > > 
> > > > > > If that is not the culprit, 38c92ff (ACPI / PM: Make 
> > > > > > __acpi_bus_get_power()
> > > > > > cover D3cold correctly) is worth ckecking too.
> > > > > > 
> > > > > > If none of the above, c2fb8a3 (USB: add NO_D3_DURING_SLEEP flag and 
> > > > > > revert
> > > > > > 151b61284776be2) is one more candidate.
> > > > > > 
> > > > > > I can't recall anything else that might be related to the symptom 
> > > > > > at the moment.
> > > > > 
> > > > > Actually, dbe9a2e and c2fb8a3 only affect system suspend, so for 
> > > > > runtime PM
> > > > > 38c92ff seems to be the only relevant one from the above.
> > > > 
> > > > I verified the problem shows up on vanilla 3.5 (just in case it was an
> > > > openSUSE problem).  I also tried reverting 38c92ff with no success.  The
> > > > symptoms appear to be that something is preventing the PCI/device
> > > > subsystem from going into auto suspend.
> > > 
> > > The number of core power management commits during the 3.5 cycle was 
> > > rather
> > > limited and none of them should affect PCI runtime PM.  I have no idea 
> > > what
> > > the root cause of that may be, quite frankly.
> > 
> > I've just realized that you said "auto suspend", which makes me think that 
> > the
> > problem may be related to USB.
> > 
> > PCI doesn't really use any kind of auto suspend for what I know, but USB 
> > does
> > and it may cause PCI USB controllers to be suspended as a result.
> 
> I'm trying to bisect this, but I've got stuck around here:
> 
> git bisect bad 2f78d8e249973f1eeb88315e6444e616c60177ae
> git bisect good 28f3d717618156c0dcd2f497d791b578a7931d87
> 
> That's around the drm tree ... unfortunately that broke a lot of the
> basics of my i915 based system (compositing and resolution) as I step
> into it.

OK, I've run the bisect as far as I can.  It looks to be in the drm
tree.  Unfortunately, this tree has several merge points, some of which
go further back than v3.4.  Unfortunately, once the bisect steps back
before 3.4, we lose the changes that gave us the power savings, making
further debugging impossible

Here's the log

git bisect start
# bad: [28a33cbc24e4256c143dce96c7d93bf423229f92] Linux 3.5
git bisect bad 28a33cbc24e4256c143dce96c7d93bf423229f92
# bad: [28a33cbc24e4256c143dce96c7d93bf423229f92] Linux 3.5
git bisect bad 28a33cbc24e4256c143dce96c7d93bf423229f92
# good: [76e10d158efb6d4516018846f60c2ab5501900bc] Linux 3.4
git bisect good 76e10d158efb6d4516018846f60c2ab5501900bc
# good: [59cd358a7a5b2f6b61faa01dae6cfda3830ac62a] Merge tag 
'perf-core-for-mingo' of 
git://git.kernel.org/pub/scm/linux/kernel/git/acme/linux into perf/urgent
git bisect good 59cd358a7a5b2f6b61faa01dae6cfda3830ac62a
# bad: [7e5b2db77b05746613516599c916a8cc2e321077] Merge branch 'upstream' of 
git://git.linux-mips.org/pub/scm/ralf/upstream-linus
git bisect bad 7e5b2db77b05746613516599c916a8cc2e321077
# good: [f9369910a6225b8d4892c3f20ae740a711cd5ace] Merge branch 'for-linus' of 
git://git.kernel.org/pub/scm/linux/kernel/git/viro/signal
git bisect good f9369910a6225b8d4892c3f20ae740a711cd5ace
# bad: [2f78d8e249973f1eeb88315e6444e616c60177ae] Merge tag 'firewire-updates' 
of git://git.kernel.org/pub/scm/linux/kernel/git/ieee1394/linux1394
git bisect bad 2f78d8e249973f1eeb88315e6444e616c60177ae
# good: [28f3d717618156c0dcd2f497d791b578a7931d87] Merge 
git://git.kernel.org/pub/scm/linux/kernel/git/davem/net
git bisect good 28f3d717618156c0dcd2f497d791b578a7931d87
# bad: [b3daeaef559d87b974c13a096582c5c70dc11061] drm/i915: move rps/emon 
function declarations
git bisect bad b3daeaef559d87b974c13a096582c5c70dc11061
# bad: [246bdbeb0f0fb14c4c085b6ed7edbab11afccd33] drm/i915: share forcewaking 
code between IVB and HSW
git bisect bad 246bdbeb0f0fb14c4c085b6ed7edbab11afccd33

If you do a gitk on the last bad and good 

gitk 
28f3d717618156c0dcd2f497d791b578a793

Massive power regression going 3.4->3.5

[Adam Jackson]

On 7/30/12 1:05 PM, James Bottomley wrote:

> Lenovo X220i
>
> The display device is
>
> 00:02.0 VGA compatible controller: Intel Corporation
> 82845G/GL[Brookdale-G]/GE Chipset Integrated Graphics Device (rev 03)
> (prog-if 00 [VGA controller])
>  Subsystem: Giga-byte Technology Device 2562
>  Flags: bus master, fast devsel, latency 0, IRQ 16
>  Memory at e000 (32-bit, prefetchable) [size=128M]
>  Memory at e820 (32-bit, non-prefetchable) [size=512K]
>  Expansion ROM at  [disabled]
>  Capabilities: 
>  Kernel driver in use: i915

What in the world?  That's an _ancient_ chip, I wouldn't expect to see 
it in a laptop that new.  I would have assumed X220i to be a Sandybridge 
like X220.

For that matter when the 845 was current Lenovo wasn't the one making 
ThinkPads.

- ajax

Re: Massive power regression going 3.4->3.5

[Adam Jackson]

On 7/30/12 1:05 PM, James Bottomley wrote:


Lenovo X220i

The display device is

00:02.0 VGA compatible controller: Intel Corporation
82845G/GL[Brookdale-G]/GE Chipset Integrated Graphics Device (rev 03)
(prog-if 00 [VGA controller])
 Subsystem: Giga-byte Technology Device 2562
 Flags: bus master, fast devsel, latency 0, IRQ 16
 Memory at e000 (32-bit, prefetchable) [size=128M]
 Memory at e820 (32-bit, non-prefetchable) [size=512K]
 Expansion ROM at  [disabled]
 Capabilities: 
 Kernel driver in use: i915


What in the world?  That's an _ancient_ chip, I wouldn't expect to see 
it in a laptop that new.  I would have assumed X220i to be a Sandybridge 
like X220.


For that matter when the 845 was current Lenovo wasn't the one making 
ThinkPads.


- ajax
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Re: Massive power regression going 3.4->3.5

[Keith Packard]

James Bottomley  writes:

> On Mon, 2012-07-30 at 09:33 -0700, Keith Packard wrote:
>> James Bottomley  writes:
>> 
>> > OK, I've run the bisect as far as I can.  It looks to be in the drm
>> > tree.  Unfortunately, this tree has several merge points, some of which
>> > go further back than v3.4.  Unfortunately, once the bisect steps back
>> > before 3.4, we lose the changes that gave us the power savings, making
>> > further debugging impossible
>> 
>> What machine is this on? There are a few 'disable some power savings'
>> patches in that list to work around issues on various machines; knowing
>> what machine you're using can isolate which ones might have had some
>> effect on power usage...
>
> Lenovo X220i

I don't see a whole lot of context from the elided email bits you'd sent
previously; can you summarize the issue in terms of how much power
savings you're losing, how you're measuring it and what's going on in
the system when the power savings is different?

Have you tried measuring power with X not running? How about with
compositing and other desktop effects disabled? 

-- 
keith.pack...@intel.com


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Massive power regression going 3.4->3.5

[Keith Packard]

James Bottomley  writes:

> On Mon, 2012-07-30 at 09:33 -0700, Keith Packard wrote:
>> James Bottomley  writes:
>> 
>> > OK, I've run the bisect as far as I can.  It looks to be in the drm
>> > tree.  Unfortunately, this tree has several merge points, some of which
>> > go further back than v3.4.  Unfortunately, once the bisect steps back
>> > before 3.4, we lose the changes that gave us the power savings, making
>> > further debugging impossible
>> 
>> What machine is this on? There are a few 'disable some power savings'
>> patches in that list to work around issues on various machines; knowing
>> what machine you're using can isolate which ones might have had some
>> effect on power usage...
>
> Lenovo X220i

I don't see a whole lot of context from the elided email bits you'd sent
previously; can you summarize the issue in terms of how much power
savings you're losing, how you're measuring it and what's going on in
the system when the power savings is different?

Have you tried measuring power with X not running? How about with
compositing and other desktop effects disabled? 

-- 
keith.packard at intel.com
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Re: Massive power regression going 3.4->3.5

[James Bottomley]

On Mon, 2012-07-30 at 09:33 -0700, Keith Packard wrote:
> James Bottomley  writes:
> 
> > OK, I've run the bisect as far as I can.  It looks to be in the drm
> > tree.  Unfortunately, this tree has several merge points, some of which
> > go further back than v3.4.  Unfortunately, once the bisect steps back
> > before 3.4, we lose the changes that gave us the power savings, making
> > further debugging impossible
> 
> What machine is this on? There are a few 'disable some power savings'
> patches in that list to work around issues on various machines; knowing
> what machine you're using can isolate which ones might have had some
> effect on power usage...

Lenovo X220i

The display device is

00:02.0 VGA compatible controller: Intel Corporation
82845G/GL[Brookdale-G]/GE Chipset Integrated Graphics Device (rev 03)
(prog-if 00 [VGA controller])
Subsystem: Giga-byte Technology Device 2562
Flags: bus master, fast devsel, latency 0, IRQ 16
Memory at e000 (32-bit, prefetchable) [size=128M]
Memory at e820 (32-bit, non-prefetchable) [size=512K]
Expansion ROM at  [disabled]
Capabilities: 
Kernel driver in use: i915


James



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Re: Massive power regression going 3.4->3.5

[Keith Packard]

James Bottomley  writes:

> OK, I've run the bisect as far as I can.  It looks to be in the drm
> tree.  Unfortunately, this tree has several merge points, some of which
> go further back than v3.4.  Unfortunately, once the bisect steps back
> before 3.4, we lose the changes that gave us the power savings, making
> further debugging impossible

What machine is this on? There are a few 'disable some power savings'
patches in that list to work around issues on various machines; knowing
what machine you're using can isolate which ones might have had some
effect on power usage...

-- 
keith.pack...@intel.com


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Massive power regression going 3.4->3.5

[Keith Packard]

James Bottomley  writes:

> OK, I've run the bisect as far as I can.  It looks to be in the drm
> tree.  Unfortunately, this tree has several merge points, some of which
> go further back than v3.4.  Unfortunately, once the bisect steps back
> before 3.4, we lose the changes that gave us the power savings, making
> further debugging impossible

What machine is this on? There are a few 'disable some power savings'
patches in that list to work around issues on various machines; knowing
what machine you're using can isolate which ones might have had some
effect on power usage...

-- 
keith.packard at intel.com
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Re: Massive power regression going 3.4->3.5

[James Bottomley]

On Mon, 2012-07-30 at 10:46 +0100, James Bottomley wrote:
> On Sun, 2012-07-29 at 21:25 +0200, Rafael J. Wysocki wrote:
> > On Sunday, July 29, 2012, Rafael J. Wysocki wrote:
> > > On Sunday, July 29, 2012, James Bottomley wrote:
> > > > On Sat, 2012-07-28 at 22:29 +0200, Rafael J. Wysocki wrote:
> > > > > On Saturday, July 28, 2012, Rafael J. Wysocki wrote:
> > > > > > On Saturday, July 28, 2012, James Bottomley wrote:
> > > > > > > One of the great things about the 3.4 kernel was the massive 
> > > > > > > increase in
> > > > > > > power savings on my x220i laptop.  With full PCI suspend, it 
> > > > > > > could get
> > > > > > > down to 6.5W in idle with a dim screen, provided I used powertop 
> > > > > > > 2.0 to
> > > > > > > activate all the tunings).  I just upgraded to 3.5 (the openSUSE
> > > > > > > tumbleweed kernel) and all the power savings are gone.  Now it's 
> > > > > > > back to
> > > > > > > its previous behaviour of idle somewhere between 16-18W.
> > > > > > 
> > > > > > Please check dbe9a2e (ACPI / PM: Make acpi_pm_device_sleep_state() 
> > > > > > follow the
> > > > > > specification) for starters.
> > > > > > 
> > > > > > If that is not the culprit, 38c92ff (ACPI / PM: Make 
> > > > > > __acpi_bus_get_power()
> > > > > > cover D3cold correctly) is worth ckecking too.
> > > > > > 
> > > > > > If none of the above, c2fb8a3 (USB: add NO_D3_DURING_SLEEP flag and 
> > > > > > revert
> > > > > > 151b61284776be2) is one more candidate.
> > > > > > 
> > > > > > I can't recall anything else that might be related to the symptom 
> > > > > > at the moment.
> > > > > 
> > > > > Actually, dbe9a2e and c2fb8a3 only affect system suspend, so for 
> > > > > runtime PM
> > > > > 38c92ff seems to be the only relevant one from the above.
> > > > 
> > > > I verified the problem shows up on vanilla 3.5 (just in case it was an
> > > > openSUSE problem).  I also tried reverting 38c92ff with no success.  The
> > > > symptoms appear to be that something is preventing the PCI/device
> > > > subsystem from going into auto suspend.
> > > 
> > > The number of core power management commits during the 3.5 cycle was 
> > > rather
> > > limited and none of them should affect PCI runtime PM.  I have no idea 
> > > what
> > > the root cause of that may be, quite frankly.
> > 
> > I've just realized that you said "auto suspend", which makes me think that 
> > the
> > problem may be related to USB.
> > 
> > PCI doesn't really use any kind of auto suspend for what I know, but USB 
> > does
> > and it may cause PCI USB controllers to be suspended as a result.
> 
> I'm trying to bisect this, but I've got stuck around here:
> 
> git bisect bad 2f78d8e249973f1eeb88315e6444e616c60177ae
> git bisect good 28f3d717618156c0dcd2f497d791b578a7931d87
> 
> That's around the drm tree ... unfortunately that broke a lot of the
> basics of my i915 based system (compositing and resolution) as I step
> into it.

OK, I've run the bisect as far as I can.  It looks to be in the drm
tree.  Unfortunately, this tree has several merge points, some of which
go further back than v3.4.  Unfortunately, once the bisect steps back
before 3.4, we lose the changes that gave us the power savings, making
further debugging impossible

Here's the log

git bisect start
# bad: [28a33cbc24e4256c143dce96c7d93bf423229f92] Linux 3.5
git bisect bad 28a33cbc24e4256c143dce96c7d93bf423229f92
# bad: [28a33cbc24e4256c143dce96c7d93bf423229f92] Linux 3.5
git bisect bad 28a33cbc24e4256c143dce96c7d93bf423229f92
# good: [76e10d158efb6d4516018846f60c2ab5501900bc] Linux 3.4
git bisect good 76e10d158efb6d4516018846f60c2ab5501900bc
# good: [59cd358a7a5b2f6b61faa01dae6cfda3830ac62a] Merge tag 
'perf-core-for-mingo' of 
git://git.kernel.org/pub/scm/linux/kernel/git/acme/linux into perf/urgent
git bisect good 59cd358a7a5b2f6b61faa01dae6cfda3830ac62a
# bad: [7e5b2db77b05746613516599c916a8cc2e321077] Merge branch 'upstream' of 
git://git.linux-mips.org/pub/scm/ralf/upstream-linus
git bisect bad 7e5b2db77b05746613516599c916a8cc2e321077
# good: [f9369910a6225b8d4892c3f20ae740a711cd5ace] Merge branch 'for-linus' of 
git://git.kernel.org/pub/scm/linux/kernel/git/viro/signal
git bisect good f9369910a6225b8d4892c3f20ae740a711cd5ace
# bad: [2f78d8e249973f1eeb88315e6444e616c60177ae] Merge tag 'firewire-updates' 
of git://git.kernel.org/pub/scm/linux/kernel/git/ieee1394/linux1394
git bisect bad 2f78d8e249973f1eeb88315e6444e616c60177ae
# good: [28f3d717618156c0dcd2f497d791b578a7931d87] Merge 
git://git.kernel.org/pub/scm/linux/kernel/git/davem/net
git bisect good 28f3d717618156c0dcd2f497d791b578a7931d87
# bad: [b3daeaef559d87b974c13a096582c5c70dc11061] drm/i915: move rps/emon 
function declarations
git bisect bad b3daeaef559d87b974c13a096582c5c70dc11061
# bad: [246bdbeb0f0fb14c4c085b6ed7edbab11afccd33] drm/i915: share forcewaking 
code between IVB and HSW
git bisect bad 246bdbeb0f0fb14c4c085b6ed7edbab11afccd33

If you do a gitk on the last bad and good 

gitk 
28f3d717618156c0dcd2f497d791b578a793