On Sun, Jul 08, 2012 at 02:17:07PM -0700, Paul E. McKenney wrote:
On Fri, Jul 06, 2012 at 01:43:29PM -0700, Josh Triplett wrote:
On Fri, Jul 06, 2012 at 09:33:38AM -0700, Paul E. McKenney wrote:
On Fri, Jul 06, 2012 at 02:00:18PM +0200, Frederic Weisbecker wrote:
--- a/arch/x86/Kconfig
On Wed, Jul 11, 2012 at 06:14:58PM +0400, Andrew Vagin wrote:
A few events are interesting not only for a current task.
For example, sched_stat_* are interesting for a task, which
wake up. For this reason, it will be good, if such events will
be delivered to a target task too.
Now a target
On Wed, Jul 11, 2012 at 04:33:41PM +0200, Peter Zijlstra wrote:
On Wed, 2012-07-11 at 16:31 +0200, Frederic Weisbecker wrote:
On Wed, Jul 11, 2012 at 06:14:58PM +0400, Andrew Vagin wrote:
A few events are interesting not only for a current task.
For example, sched_stat_* are interesting
On Wed, Jul 11, 2012 at 04:38:19PM +0200, Peter Zijlstra wrote:
On Wed, 2012-07-11 at 16:36 +0200, Frederic Weisbecker wrote:
In this case he can just record sched wakeup as well. With sched_switch
+ sched_wakeup, he'll unlikely lose events.
With sched_stat_sleep he will lose events
On Wed, Jul 11, 2012 at 04:55:08PM +0200, Peter Zijlstra wrote:
On Wed, 2012-07-11 at 16:48 +0200, Frederic Weisbecker wrote:
On Wed, Jul 11, 2012 at 04:38:19PM +0200, Peter Zijlstra wrote:
On Wed, 2012-07-11 at 16:36 +0200, Frederic Weisbecker wrote:
In this case he can just record
On Wed, Jul 11, 2012 at 05:12:04PM +0200, Peter Zijlstra wrote:
On Wed, 2012-07-11 at 16:55 +0200, Peter Zijlstra wrote:
Right.. back when I did that the plan was to make PERF_SAMPLE_PERIOD fix
that, of course that never seemed to have happened.
With PERF_SAMPLE_PERIOD you can simply
and the overhead
is lowered in the off-case. This can be even better if we use
jump labels later.
Thanks.
git://github.com/fweisbec/linux-dynticks.git
rcu/user-2
Frederic Weisbecker (11):
rcu: Settle config for userspace extended quiescent state
rcu: Allow rcu_user_enter()/exit
Clear the syscalls hook of a task when it's scheduled out so that if
the task migrates, it doesn't run the syscall slow path on a CPU
that might not need it.
Also set the syscalls hook on the next task if needed.
Signed-off-by: Frederic Weisbecker fweis...@gmail.com
Cc: Alessio Igor Bogani abog
Add syscall slow path hooks to notify syscall entry
and exit on CPUs that want to support userspace RCU
extended quiescent state.
Signed-off-by: Frederic Weisbecker fweis...@gmail.com
Cc: Alessio Igor Bogani abog...@kernel.org
Cc: Andrew Morton a...@linux-foundation.org
Cc: Avi Kivity
Add necessary hooks to x86 exception for userspace
RCU extended quiescent state support.
This includes traps, page fault, debug exceptions, etc...
Signed-off-by: Frederic Weisbecker fweis...@gmail.com
Cc: Alessio Igor Bogani abog...@kernel.org
Cc: Andrew Morton a...@linux-foundation.org
Cc: Avi
This way we can exit the RCU extended quiescent state before
we schedule a new task from irq/exception exit.
Signed-off-by: Frederic Weisbecker fweis...@gmail.com
Cc: Alessio Igor Bogani abog...@kernel.org
Cc: Andrew Morton a...@linux-foundation.org
Cc: Avi Kivity a...@redhat.com
Cc: Chris
back rcu_user_enter() after this function because we know we are
going to userspace from there.
This complete support for userspace RCU extended quiescent state
in x86-64.
Signed-off-by: Frederic Weisbecker fweis...@gmail.com
Cc: Alessio Igor Bogani abog...@kernel.org
Cc: Andrew Morton a...@linux
Provide a config option that enables the userspace
RCU extended quiescent state on every CPUs by default.
This is for testing purpose.
Signed-off-by: Frederic Weisbecker fweis...@gmail.com
Cc: Alessio Igor Bogani abog...@kernel.org
Cc: Andrew Morton a...@linux-foundation.org
Cc: Avi Kivity
before
we call it.
To solve this, just call rcu_user_exit() in the beginning of
preempt_schedule_irq().
Signed-off-by: Frederic Weisbecker fweis...@gmail.com
Cc: Alessio Igor Bogani abog...@kernel.org
Cc: Andrew Morton a...@linux-foundation.org
Cc: Avi Kivity a...@redhat.com
Cc: Chris Metcalf cmetc
Create a new config option under the RCU menu that put
CPUs under RCU extended quiescent state (as in dynticks
idle mode) when they run in userspace. This require
some contribution from architectures to hook into kernel
and userspace boundaries.
Signed-off-by: Frederic Weisbecker fweis
userspace before calling rcu_user_exit().
Signed-off-by: Frederic Weisbecker fweis...@gmail.com
Cc: Alessio Igor Bogani abog...@kernel.org
Cc: Andrew Morton a...@linux-foundation.org
Cc: Avi Kivity a...@redhat.com
Cc: Chris Metcalf cmetc...@tilera.com
Cc: Christoph Lameter c...@linux.com
Cc: Geoff
By default we don't want to enter into RCU extended quiescent
state while in userspace because doing this produces some overhead
(eg: use of syscall slowpath). Set it off by default and ready to
run when some feature like adaptive tickless need it.
Signed-off-by: Frederic Weisbecker fweis
() and the irq has called
rcu_irq_exit() already.
Create a new API schedule_user() that calls schedule() inside
rcu_user_exit()-rcu_user_enter() in order to protect it. Archs
will need to rely on it now to implement user preemption safely.
Signed-off-by: Frederic Weisbecker fweis...@gmail.com
Cc: Alessio Igor
On Tue, Jul 03, 2012 at 03:38:39PM +0400, Glauber Costa wrote:
On 06/29/2012 02:25 AM, Andrew Morton wrote:
On Thu, 28 Jun 2012 13:01:23 +0400
Glauber Costa glom...@parallels.com wrote:
...
OK, that all sounds convincing ;) Please summarise and capture this
discussion in the
On Sun, Jul 22, 2012 at 02:14:26PM +0200, Jiri Olsa wrote:
Adding copy_from_user_nmi_nochk that provides the best effort
copy regardless the requesting size crossing the task boundary.
This is going to be useful for stack dump we need in post
DWARF CFI based unwind, where we have predefined
if needed in the future.
Signed-off-by: Jiri Olsa jo...@redhat.com
Original-patch-by: Frederic Weisbecker fweis...@gmail.com
Acked-by: Frederic Weisbecker fweis...@gmail.com
--
To unsubscribe from this list: send the line unsubscribe linux-kernel in
the body of a message to majord...@vger.kernel.org
.
This is going to be useful to bring Dwarf CFI based stack
unwinding on top of samples.
Signed-off-by: Jiri Olsa jo...@redhat.com
Original-patch-by: Frederic Weisbecker fweis...@gmail.com
Acked-by: Frederic Weisbecker fweis...@gmail.com
--
To unsubscribe from this list: send the line unsubscribe
2012/12/3 Alex Shi alex@intel.com:
It is impossible to miss a task allowed cpu in a eligible group.
And since find_idlest_group only return a different group which
excludes old cpu, it's also imporissible to find a new cpu same as old
cpu.
Is it possible for weighted_cpuload() to return
2012/12/3 Alex Shi alex@intel.com:
There is 4 situations in the function:
1, no task allowed group;
so min_load = ULONG_MAX, this_load = 0, idlest = NULL
2, only local group task allowed;
so min_load = ULONG_MAX, this_load assigned, idlest = NULL
3, only non-local task
2012/12/7 Alex Shi alex@intel.com:
On 12/07/2012 01:50 AM, Frederic Weisbecker wrote:
2012/12/3 Alex Shi alex@intel.com:
It is impossible to miss a task allowed cpu in a eligible group.
And since find_idlest_group only return a different group which
excludes old cpu, it's also
2012/12/7 Alex Shi alex@intel.com:
On 12/07/2012 08:56 AM, Frederic Weisbecker wrote:
2012/12/3 Alex Shi alex@intel.com:
There is 4 situations in the function:
1, no task allowed group;
so min_load = ULONG_MAX, this_load = 0, idlest = NULL
2, only local group task allowed
to printk that should likely
be applied in some form for -rc1 or earlier:
Sylvain Munaut's (cc'd) print_time fix:
https://patchwork.kernel.org/patch/1845971/
I don't know of anything else that likely will
or should be applied before -rc1.
Frederic Weisbecker (also cc'd) has a printk nohz
2012/12/8 Ingo Molnar mi...@kernel.org:
* Frederic Weisbecker fweis...@gmail.com wrote:
Ingo,
Please pull the printk support in dynticks mode patches that can
be found at:
git://git.kernel.org/pub/scm/linux/kernel/git/frederic/linux-dynticks.git
tags/printk-dynticks-for-mingo-v2
Thanx, Paul
Frederic Weisbecker (1):
context_tracking: New context tracking susbsystem
arch/Kconfig | 15 ++--
arch/x86/Kconfig |2 +-
arch/x86/include/asm/{rcu.h = context_tracking.h
2012/11/20 Steven Rostedt rost...@goodmis.org:
On Mon, 2012-11-19 at 17:27 -0700, Hakan Akkan wrote:
I suggest to rather define a tunable timekeeping duty CPU affinity in
a cpumask file at /sys/devices/system/cpu/timekeeping and a toggle at
/sys/devices/system/cpu/cpuX/timekeeping (like
time accounting APIs)
Thanks.
---
Some more cputime cleanups:
* Get rid of underscores polluting the vtime namespace
* Consolidate context switch and tick handling
* Improve debuggability by detecting irq unsafe callers
Signed-off-by: Frederic Weisbecker fweis...@gmail.com
---
Frederic
() for this specific
case so that we can remove the underscore prefix on other
vtime functions.
Signed-off-by: Frederic Weisbecker fweis...@gmail.com
Reviewed-by: Steven Rostedt rost...@goodmis.org
Cc: Peter Zijlstra pet...@infradead.org
Cc: Ingo Molnar mi...@kernel.org
Cc: Thomas Gleixner t...@linutronix.de
Cc
All vtime implementations just flush the user time on process
tick. Consolidate that in generic code by calling a user time
accounting helper. This avoids an indirect call in ia64 and
prepare to also consolidate vtime context switch code.
Signed-off-by: Frederic Weisbecker fweis...@gmail.com
vtime_account() is only called from irq entry. irqs
are always disabled at this point so we can safely
remove the irq disabling guards on that function.
Signed-off-by: Frederic Weisbecker fweis...@gmail.com
Reviewed-by: Steven Rostedt rost...@goodmis.org
Cc: Peter Zijlstra pet...@infradead.org
Cc
or we missed something.
Suggested-by: Steven Rostedt rost...@goodmis.org
Signed-off-by: Frederic Weisbecker fweis...@gmail.com
Cc: Peter Zijlstra pet...@infradead.org
Cc: Ingo Molnar mi...@kernel.org
Cc: Thomas Gleixner t...@linutronix.de
Cc: Steven Rostedt rost...@goodmis.org
Cc: Paul Gortmaker
own implementation.
Signed-off-by: Frederic Weisbecker fweis...@gmail.com
Reviewed-by: Steven Rostedt rost...@goodmis.org
Cc: Peter Zijlstra pet...@infradead.org
Cc: Ingo Molnar mi...@kernel.org
Cc: Thomas Gleixner t...@linutronix.de
Cc: Steven Rostedt rost...@goodmis.org
Cc: Paul Gortmaker
Hi,
Not vtime related that time, just a few supplementary cleanups on the part
that computes the adjusted cputime values.
Thanks.
Frederic Weisbecker (3):
cputime: Move thread_group_cputime() to sched code
cputime: Rename thread_group_times to thread_group_cputime_adjusted
cputime
of thread_group_cputime() that does some stabilization
on the raw cputime values. ie here: scale on top of CFS runtime
stats and bound lower value for monotonicity.
Signed-off-by: Frederic Weisbecker fweis...@gmail.com
Cc: Ingo Molnar mi...@kernel.org
Cc: Peter Zijlstra pet...@infradead.org
Cc: Thomas Gleixner t
in the group and the
previous adjusted snapshot of the whole group from the signal
structure.
Just consolidate the common code that does the adjustment. These
functions just need to fetch the values from the appropriate
source.
Signed-off-by: Frederic Weisbecker fweis...@gmail.com
Cc: Ingo Molnar mi
thread_group_cputime() is a general cputime API that is not only
used by posix cpu timer. Let's move this helper to sched code.
Signed-off-by: Frederic Weisbecker fweis...@gmail.com
Cc: Ingo Molnar mi...@kernel.org
Cc: Peter Zijlstra pet...@infradead.org
Cc: Thomas Gleixner t...@linutronix.de
Cc
2012/11/25 Paul Gortmaker paul.gortma...@windriver.com:
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -433,6 +433,11 @@ struct cpu_itimer {
u32 incr_error;
};
+struct cputime {
+ cputime_t utime;
+ cputime_t stime;
+};
+
Hi Frederic,
This new struct
2012/11/26 Steven Rostedt rost...@goodmis.org:
On Fri, 2012-11-23 at 15:21 +0100, Frederic Weisbecker wrote:
We have thread_group_cputime() and thread_group_times(). The naming
doesn't provide enough information about the difference between
these two APIs.
To lower the confusion, rename
2012/11/6 Gilad Ben-Yossef gi...@benyossef.com:
On Sat, Nov 3, 2012 at 6:09 PM, Frederic Weisbecker fweis...@gmail.com
wrote:
diff --git a/arch/Kconfig b/arch/Kconfig
index 366ec06..3855e06 100644
--- a/arch/Kconfig
+++ b/arch/Kconfig
@@ -300,15 +300,15 @@ config SECCOMP_FILTER
2012/11/27 Li Zhong zh...@linux.vnet.ibm.com:
I noticed some warnings complaining about dynticks_nesting value, like
[ 267.545032] [ cut here ]
[ 267.545032] WARNING: at kernel/rcutree.c:382 rcu_eqs_enter+0xab/0xc0()
[ 267.545032] Hardware name: Bochs
[
2012/11/27 Gleb Natapov g...@redhat.com:
On Tue, Nov 27, 2012 at 01:15:25PM +0800, Li Zhong wrote:
@@ -247,10 +247,17 @@ do_async_page_fault(struct pt_regs *regs, unsigned
long error_code)
break;
case KVM_PV_REASON_PAGE_NOT_PRESENT:
/* page is swapped out
2012/11/27 Li Zhong zh...@linux.vnet.ibm.com:
I noticed some warnings complaining about dynticks_nesting value, like
[ 267.545032] [ cut here ]
[ 267.545032] WARNING: at kernel/rcutree.c:382 rcu_eqs_enter+0xab/0xc0()
[ 267.545032] Hardware name: Bochs
[
2012/11/27 Gleb Natapov g...@redhat.com:
For KVM_PV_REASON_PAGE_NOT_PRESENT it behaves like an exception.
Ok.
There seem to be a bug in kvm_async_pf_task_wait(). Using
idle_cpu(cpu) to find out if the current task is the idle task may not
work if there is pending wake up. Me may schedule another
2012/11/27 Li Zhong zh...@linux.vnet.ibm.com:
@@ -247,10 +247,17 @@ do_async_page_fault(struct pt_regs *regs, unsigned long
error_code)
break;
case KVM_PV_REASON_PAGE_NOT_PRESENT:
/* page is swapped out by the host. */
- rcu_irq_enter();
2012/11/27 Paul E. McKenney paul...@linux.vnet.ibm.com:
It is OK to call rcu_irq_exit() without a matching rcu_irq_enter() -only-
if you have also called rcu_idle_exit() since the last rcu_idle_enter().
There will be a similar rule for rcu_user_exit().
More generally, it is OK to call
2012/11/27 Li Zhong zh...@linux.vnet.ibm.com:
I noticed some warnings complaining about dynticks_nesting value, like
[ 267.545032] [ cut here ]
[ 267.545032] WARNING: at kernel/rcutree.c:382 rcu_eqs_enter+0xab/0xc0()
[ 267.545032] Hardware name: Bochs
[
2012/11/27 Paul E. McKenney paul...@linux.vnet.ibm.com:
On Tue, Nov 27, 2012 at 04:56:30PM +0100, Frederic Weisbecker wrote:
2012/11/27 Gleb Natapov g...@redhat.com:
For KVM_PV_REASON_PAGE_NOT_PRESENT it behaves like an exception.
Ok.
There seem to be a bug in kvm_async_pf_task_wait
2012/11/27 Gleb Natapov g...@redhat.com:
On Tue, Nov 27, 2012 at 04:56:30PM +0100, Frederic Weisbecker wrote:
2012/11/27 Gleb Natapov g...@redhat.com:
For KVM_PV_REASON_PAGE_NOT_PRESENT it behaves like an exception.
Ok.
There seem to be a bug in kvm_async_pf_task_wait(). Using
idle_cpu(cpu
2012/11/27 Gleb Natapov g...@redhat.com:
diff --git a/arch/x86/kernel/kvm.c b/arch/x86/kernel/kvm.c
index 4180a87..636800d 100644
--- a/arch/x86/kernel/kvm.c
+++ b/arch/x86/kernel/kvm.c
@@ -113,7 +113,7 @@ void kvm_async_pf_task_wait(u32 token)
int cpu, idle;
cpu =
2012/11/27 Gleb Natapov g...@redhat.com:
On Tue, Nov 27, 2012 at 06:30:32PM +0100, Frederic Weisbecker wrote:
2012/11/27 Gleb Natapov g...@redhat.com:
diff --git a/arch/x86/kernel/kvm.c b/arch/x86/kernel/kvm.c
index 4180a87..636800d 100644
--- a/arch/x86/kernel/kvm.c
+++ b/arch/x86
2012/11/27 Gleb Natapov g...@redhat.com:
What is the semantics of enter_idle()/exit_idle(), what are they used for?
It's used by drivers/idle/i7300_idle.c for some tracking. I don't know much
the details.
enter_idle() is called right before the CPU is set to lower power mode: hlt()
exit_idle()
2012/11/27 Frederic Weisbecker fweis...@gmail.com:
2012/11/27 Gleb Natapov g...@redhat.com:
What is the semantics of enter_idle()/exit_idle(), what are they used for?
It's used by drivers/idle/i7300_idle.c for some tracking. I don't know much
the details.
enter_idle() is called right before
2012/11/26 Steven Rostedt rost...@goodmis.org:
OK, let's take a look at the other version now:
void thread_group_times(struct task_struct *p, cputime_t *ut, cputime_t *st)
So this does the same thing than thread_group_cputime(), ie: fetch the
raw cputime stats from the task/signal struct, with
2012/11/28 Li Zhong zh...@linux.vnet.ibm.com:
Thank you all for the review and education.
Below are my current understandings and an update version. Would you
please help to review it again and give your comments?
Thanks, Zhong
Now it seems to me that it is legal to call
2012/11/28 Gleb Natapov g...@redhat.com:
On Wed, Nov 28, 2012 at 01:55:42PM +0100, Frederic Weisbecker wrote:
Yes but if rcu_irq_*() calls are fine to be called there, and I
believe they are because exception_enter() exits the user mode, we
should start to protect there right now instead
Hi,
Changes since v1 address Steven Rostedt and Paul Gortmaker reviews:
- More comments to distinguish struct cputime / struct task_cputime [3/4]
- Comment the reasons and the details for cputime adjustment [4/4]
Thanks.
Frederic Weisbecker (4):
cputime: Move thread_group_cputime() to sched
thread_group_cputime() is a general cputime API that is not only
used by posix cpu timer. Let's move this helper to sched code.
Signed-off-by: Frederic Weisbecker fweis...@gmail.com
Cc: Ingo Molnar mi...@kernel.org
Cc: Peter Zijlstra pet...@infradead.org
Cc: Thomas Gleixner t...@linutronix.de
Cc
in the group and the
previous adjusted snapshot of the whole group from the signal
structure.
Just consolidate the common code that does the adjustment. These
functions just need to fetch the values from the appropriate
source.
Signed-off-by: Frederic Weisbecker fweis...@gmail.com
Cc: Ingo Molnar mi
of thread_group_cputime() that does some stabilization
on the raw cputime values. ie here: scale on top of CFS runtime
stats and bound lower value for monotonicity.
Signed-off-by: Frederic Weisbecker fweis...@gmail.com
Cc: Ingo Molnar mi...@kernel.org
Cc: Peter Zijlstra pet...@infradead.org
Cc: Thomas Gleixner t
The reason for the scaling and monotonicity correction performed
by cputime_adjust() may not be immediately clear to the reviewer.
Add some comments to explain what happens there.
Signed-off-by: Frederic Weisbecker fweis...@gmail.com
Cc: Ingo Molnar mi...@kernel.org
Cc: Peter Zijlstra pet
anytime in order to minimize the
overhead associated to user hooks.
Signed-off-by: Frederic Weisbecker fweis...@gmail.com
Cc: Alessio Igor Bogani abog...@kernel.org
Cc: Andrew Morton a...@linux-foundation.org
Cc: Avi Kivity a...@redhat.com
Cc: Chris Metcalf cmetc...@tilera.com
Cc: Christoph Lameter c
. McKenney paul...@linux.vnet.ibm.com
Signed-off-by: Frederic Weisbecker fweis...@gmail.com
Cc: Alessio Igor Bogani abog...@kernel.org
Cc: Andrew Morton a...@linux-foundation.org
Cc: Avi Kivity a...@redhat.com
Cc: Chris Metcalf cmetc...@tilera.com
Cc: Christoph Lameter c...@linux.com
Cc: Geoff Levand ge
This is in preparation for the full dynticks feature. While
remotely reading the cputime of a task running in a full
dynticks CPU, we'll need to do some extra-computation. This
way we can account the time it spent tickless in userspace
since its last cputime snapshot.
Signed-off-by: Frederic
running. But let's use this KISS solution for now.
Signed-off-by: Frederic Weisbecker fweis...@gmail.com
Cc: Alessio Igor Bogani abog...@kernel.org
Cc: Andrew Morton a...@linux-foundation.org
Cc: Avi Kivity a...@redhat.com
Cc: Chris Metcalf cmetc...@tilera.com
Cc: Christoph Lameter c...@linux.com
Cc
Just to avoid confusion.
Signed-off-by: Frederic Weisbecker fweis...@gmail.com
Cc: Alessio Igor Bogani abog...@kernel.org
Cc: Andrew Morton a...@linux-foundation.org
Cc: Avi Kivity a...@redhat.com
Cc: Chris Metcalf cmetc...@tilera.com
Cc: Christoph Lameter c...@linux.com
Cc: Geoff Levand ge
tickless because scheduler_tick() is not there to maintain
it.
Signed-off-by: Frederic Weisbecker fweis...@gmail.com
Cc: Alessio Igor Bogani abog...@kernel.org
Cc: Andrew Morton a...@linux-foundation.org
Cc: Avi Kivity a...@redhat.com
Cc: Chris Metcalf cmetc...@tilera.com
Cc: Christoph Lameter c
things to be done from scheduler_tick()]
[ Included build fix from Geoff Levand ]
Signed-off-by: Frederic Weisbecker fweis...@gmail.com
Cc: Alessio Igor Bogani abog...@kernel.org
Cc: Andrew Morton a...@linux-foundation.org
Cc: Avi Kivity a...@redhat.com
Cc: Chris Metcalf cmetc...@tilera.com
Cc
[ ** BUGGY PATCH: I need to put more thinking into this ** ]
We want the nohz load balancer to be an idle CPU, thus
move that selection to strict dyntick idle logic.
Signed-off-by: Frederic Weisbecker fweis...@gmail.com
Cc: Alessio Igor Bogani abog...@kernel.org
Cc: Andrew Morton a...@linux
is in dyntick-idle mode?
Signed-off-by: Frederic Weisbecker fweis...@gmail.com
Cc: Alessio Igor Bogani abog...@kernel.org
Cc: Andrew Morton a...@linux-foundation.org
Cc: Avi Kivity a...@redhat.com
Cc: Chris Metcalf cmetc...@tilera.com
Cc: Christoph Lameter c...@linux.com
Cc: Geoff Levand ge
Wake up a CPU when a timer list timer is enqueued there and
the CPU is in full dynticks mode. Sending an IPI to it makes
it reconsidering the next timer to program on top of recent
updates.
Signed-off-by: Frederic Weisbecker fweis...@gmail.com
Cc: Alessio Igor Bogani abog...@kernel.org
Cc: Andrew
When a CPU in full dynticks mode doesn't respond to complete
a grace period, issue it a specific IPI so that it restarts
the tick and chases a quiescent state.
Signed-off-by: Frederic Weisbecker fweis...@gmail.com
Cc: Alessio Igor Bogani abog...@kernel.org
Cc: Andrew Morton a...@linux
idle_balance() is called from schedule() right before we schedule the
idle task. It needs to record the idle timestamp at that time and for
this the rq clock must be accurate. If the CPU is running tickless
we need to update the rq clock manually.
Signed-off-by: Frederic Weisbecker fweis
isolation:
https://github.com/gby/linux/wiki
But keep in mind that my tree is not yet ready for serious production.
Happy Christmas, new year or whatever end of the world.
---
Frederic Weisbecker (32):
irq_work: Fix racy IRQ_WORK_BUSY flag setting
irq_work: Fix racy check on work
Not for merge. This may become a real tracepoint.
Signed-off-by: Frederic Weisbecker fweis...@gmail.com
Cc: Alessio Igor Bogani abog...@kernel.org
Cc: Andrew Morton a...@linux-foundation.org
Cc: Avi Kivity a...@redhat.com
Cc: Chris Metcalf cmetc...@tilera.com
Cc: Christoph Lameter c...@linux.com
In this function we are making use of rq-clock right before the
update of the rq clock, let's just call update_rq_clock() just
before that to avoid using a stale rq clock value.
Signed-off-by: Frederic Weisbecker fweis...@gmail.com
Cc: Alessio Igor Bogani abog...@kernel.org
Cc: Andrew Morton
clock
before reading it.
Signed-off-by: Frederic Weisbecker fweis...@gmail.com
Cc: Alessio Igor Bogani abog...@kernel.org
Cc: Andrew Morton a...@linux-foundation.org
Cc: Avi Kivity a...@redhat.com
Cc: Chris Metcalf cmetc...@tilera.com
Cc: Christoph Lameter c...@linux.com
Cc: Geoff Levand ge
: OTOH we don't want to handle a locally started
grace period, this should be offloaded for rcu_nocb CPUs.
What we want is to be kicked if we stay dynticks in the kernel
for too long (ie: to report a quiescent state).
rcu_pending() is perhaps an overkill just for that.
Signed-off-by: Frederic
Because the sched_class::put_prev_task() callback of rt and fair
classes are referring to the rq clock to update their runtime
statistics. A CPU running in tickless mode may carry a stale value.
We need to update it there.
Signed-off-by: Frederic Weisbecker fweis...@gmail.com
Cc: Alessio Igor
On a full dynticks CPU, we want the RCU callbacks to be
offlined to another CPU, otherwise we need to keep
the tick to wait for the grace period completion.
Ensure the full dynticks CPU is also an rcu_nocb one.
Signed-off-by: Frederic Weisbecker fweis...@gmail.com
Cc: Alessio Igor Bogani abog
-by: Frederic Weisbecker fweis...@gmail.com
Cc: Alessio Igor Bogani abog...@kernel.org
Cc: Andrew Morton a...@linux-foundation.org
Cc: Avi Kivity a...@redhat.com
Cc: Chris Metcalf cmetc...@tilera.com
Cc: Christoph Lameter c...@linux.com
Cc: Geoff Levand ge...@infradead.org
Cc: Gilad Ben Yossef gi
native
virtual based cputime accounting which hooks on low level code and use
a cpu hardware clock. Precision is not the goal of this though.
- There is probably more overhead than a native virtual based cputime
accounting. But this relies on hooks that are already set anyway.
Signed-off-by: Frederic
-off-by: Frederic Weisbecker fweis...@gmail.com
Cc: Alessio Igor Bogani abog...@kernel.org
Cc: Andrew Morton a...@linux-foundation.org
Cc: Avi Kivity a...@redhat.com
Cc: Chris Metcalf cmetc...@tilera.com
Cc: Christoph Lameter c...@linux.com
Cc: Geoff Levand ge...@infradead.org
Cc: Gilad Ben Yossef gi
manually in case the CPU runs
tickless because ttwu_do_wakeup() calls check_preempt_wakeup().
Signed-off-by: Frederic Weisbecker fweis...@gmail.com
Cc: Alessio Igor Bogani abog...@kernel.org
Cc: Andrew Morton a...@linux-foundation.org
Cc: Avi Kivity a...@redhat.com
Cc: Chris Metcalf cmetc
Not for merge, just for debugging.
Signed-off-by: Frederic Weisbecker fweis...@gmail.com
Cc: Alessio Igor Bogani abog...@kernel.org
Cc: Andrew Morton a...@linux-foundation.org
Cc: Avi Kivity a...@redhat.com
Cc: Chris Metcalf cmetc...@tilera.com
Cc: Christoph Lameter c...@linux.com
Cc: Geoff
This subsystem lacks many explanations on its purpose and
design. Add these missing comments.
Reported-by: Andrew Morton a...@linux-foundation.org
Signed-off-by: Frederic Weisbecker fweis...@gmail.com
Cc: Alessio Igor Bogani abog...@kernel.org
Cc: Andrew Morton a...@linux-foundation.org
Cc: Avi
out of tree
user.
Let's remove it.
Signed-off-by: Frederic Weisbecker fweis...@gmail.com
Cc: Alessio Igor Bogani abog...@kernel.org
Cc: Andrew Morton a...@linux-foundation.org
Cc: Avi Kivity a...@redhat.com
Cc: Chris Metcalf cmetc...@tilera.com
Cc: Christoph Lameter c...@linux.com
Cc: Geoff Levand
2012/12/21 Steven Rostedt rost...@goodmis.org:
On Thu, 2012-12-20 at 19:32 +0100, Frederic Weisbecker wrote:
kernel/time/tick-sched.c:517:6: error: have_full_nohz_mask undeclared
(first use in this function)
--- a/kernel/time/tick-sched.c
+++ b/kernel/time/tick-sched.c
@@ -112,7 +112,8
2012/12/21 Steven Rostedt rost...@goodmis.org:
@@ -601,6 +612,7 @@ void thread_group_cputime_adjusted(struct task_struct *p,
cputime_t *ut, cputime
thread_group_cputime(p, cputime);
cputime_adjust(cputime, p-signal-prev_cputime, ut, st);
}
+#endif /*
2012/12/21 Steven Rostedt rost...@goodmis.org:
On Thu, 2012-12-20 at 19:32 +0100, Frederic Weisbecker wrote:
--- a/include/linux/init_task.h
+++ b/include/linux/init_task.h
@@ -10,6 +10,7 @@
#include linux/pid_namespace.h
#include linux/user_namespace.h
#include linux/securebits.h
2012/12/21 Steven Rostedt rost...@goodmis.org:
On Thu, 2012-12-20 at 19:32 +0100, Frederic Weisbecker wrote:
Let's imagine you have 4 CPUs. We keep the CPU 0 to offline RCU callbacks
there and to
handle the timekeeping. We set the rest as full dynticks. So you need the
following kernel
2012/12/26 Li Zhong zh...@linux.vnet.ibm.com:
On Thu, 2012-12-20 at 19:32 +0100, Frederic Weisbecker wrote:
diff --git a/init/Kconfig b/init/Kconfig
index 60579d6..a64b3e8 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -340,7 +340,9 @@ config TICK_CPU_ACCOUNTING
config
2012/12/26 Namhyung Kim namhy...@kernel.org:
Hi Frederic,
On Thu, 20 Dec 2012 19:33:07 +0100, Frederic Weisbecker wrote:
When a CPU is in full dynticks mode, try to switch
it to nohz mode from the interrupt exit path if it is
running a single non-idle task.
Then restart the tick
.
Happy new year!
---
Frederic Weisbecker (35):
irq_work: Fix racy IRQ_WORK_BUSY flag setting
irq_work: Fix racy check on work pending flag
irq_work: Remove CONFIG_HAVE_IRQ_WORK
nohz: Add API to check tick state
irq_work: Don't stop the tick with pending works
native
virtual based cputime accounting which hooks on low level code and use
a cpu hardware clock. Precision is not the goal of this though.
- There is probably more overhead than a native virtual based cputime
accounting. But this relies on hooks that are already set anyway.
Signed-off-by: Frederic
This is in preparation for the full dynticks feature. While
remotely reading the cputime of a task running in a full
dynticks CPU, we'll need to do some extra-computation. This
way we can account the time it spent tickless in userspace
since its last cputime snapshot.
Signed-off-by: Frederic
running. But let's use this KISS solution for now.
Signed-off-by: Frederic Weisbecker fweis...@gmail.com
Cc: Alessio Igor Bogani abog...@kernel.org
Cc: Andrew Morton a...@linux-foundation.org
Cc: Chris Metcalf cmetc...@tilera.com
Cc: Christoph Lameter c...@linux.com
Cc: Geoff Levand ge
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