On 27.03.2012 14:26, Gleb Natapov wrote:
On Tue, Mar 27, 2012 at 02:20:23PM +0200, Peter Lieven wrote:
On 27.03.2012 12:00, Gleb Natapov wrote:
On Tue, Mar 27, 2012 at 11:26:29AM +0200, Peter Lieven wrote:
On 27.03.2012 11:23, Vadim Rozenfeld wrote:
On Tuesday, March 27, 2012 10:56:05 AM Gleb Natapov wrote:
On Mon, Mar 26, 2012 at 10:11:43PM +0200, Vadim Rozenfeld wrote:
On Monday, March 26, 2012 08:54:50 PM Peter Lieven wrote:
On 26.03.2012 20:36, Vadim Rozenfeld wrote:
On Monday, March 26, 2012 07:52:49 PM Gleb Natapov wrote:
On Mon, Mar 26, 2012 at 07:46:03PM +0200, Vadim Rozenfeld wrote:
On Monday, March 26, 2012 07:00:32 PM Peter Lieven wrote:
On 22.03.2012 10:38, Vadim Rozenfeld wrote:
On Thursday, March 22, 2012 10:52:42 AM Peter Lieven wrote:
On 22.03.2012 09:48, Vadim Rozenfeld wrote:
On Thursday, March 22, 2012 09:53:45 AM Gleb Natapov wrote:
On Wed, Mar 21, 2012 at 06:31:02PM +0100, Peter Lieven wrote:
On 21.03.2012 12:10, David Cure wrote:
hello,
Le Tue, Mar 20, 2012 at 02:38:22PM +0200, Gleb Natapov
ecrivait :
Try to add<feature policy='disable' name='hypervisor'/>
to cpu definition in XML and check command line.
ok I try this but I can't use<cpu model> to map the
host cpu
(my libvirt is 0.9.8) so I use :
<cpu match='exact'>
<model>Opteron_G3</model>
<feature policy='disable' name='hypervisor'/>
</cpu>
(the physical server use Opteron CPU).
The log is here :
http://www.roullier.net/Report/report-3.2-vhost-net-1vcpu-cp
u.tx t.gz
And now with only 1 vcpu, the response time is 8.5s, great
improvment. We keep this configuration for production : we
check the response time when some other users are
connected.
please keep in mind, that setting -hypervisor, disabling hpet
and only one vcpu
makes windows use tsc as clocksource. you have to make sure,
that your vm is not switching between physical sockets on
your system and that you have constant_tsc feature to have a
stable tsc between the cores in the same socket. its also
likely that the vm will crash when live migrated.
All true. I asked to try -hypervisor only to verify where we
loose performance. Since you get good result with it frequent
access to PM timer is probably the reason. I do not recommend
using -hypervisor for production!
@gleb: do you know whats the state of in-kernel hyper-v
timers?
Vadim is working on it. I'll let him answer.
It would be nice to have synthetic timers supported. But, at
the moment, I'm only researching this feature.
So it will take months at least?
I would say weeks.
Is there a way, we could contribute and help you with this?
Hi Peter,
You are welcome to add an appropriate handler.
I think Vadim refers to this HV MSR
http://msdn.microsoft.com/en-us/library/windows/hardware/ff542633%28
v=vs .85 %29.aspx
This one is pretty simple to support. Please see attachments for more
details. I was thinking about synthetic timers
http://msdn.microsoft.com/en-
us/library/windows/hardware/ff542758(v=vs.85).aspx
is this what microsoft qpc uses as clocksource in hyper-v?
Yes, it should be enough for Win7 / W2K8R2.
To clarify the thing that microsoft qpc uses is what is implemented by
the patch Vadim attached to his previous email. But I believe that
additional qemu patch is needed for Windows to actually use it.
You are right.
bits 1 and 9 must be set to on in leaf 0x40000003 and HPET
should be completely removed from ACPI.
could you advise how to do this and/or make a patch?
the stuff you send yesterday is for qemu, right? would
it be possible to use it in qemu-kvm also?
No, they are for kernel.
i meant the qemu.diff file.
Yes, I missed the second attachment.
if i understand correctly i have to pass -cpu host,+hv_refcnt to qemu?
Looks like it.
ok, so it would be interesting if it helps to avoid the pmtimer reads
we observed earlier. right?
peter
--
Gleb.
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