On 27.03.2012 17:44, Vadim Rozenfeld wrote:
On Tuesday, March 27, 2012 04:06:13 PM Peter Lieven wrote:
On 27.03.2012 14:29, Gleb Natapov wrote:
On Tue, Mar 27, 2012 at 02:28:04PM +0200, Peter Lieven wrote:
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-1v
cpu-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/ff542
633%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?
Yes.
first feedback: performance seems to be amazing. i cannot confirm that
it breaks hv_spinlocks, hv_vapic and hv_relaxed.
why did you assume this?
I didn't mean that hv_refcnt will break any other hyper-v features.
I just want to say that turning hv_refcnt on (as any other hv_ option) will
crash Win8 on boot-up.
yes, i got it meanwhile ;-)
let me know what you think should be done to further test
the refcnt implementation.
i would suggest to return at least 0xFFFFFFFF if msr 0x40000021
is read.
peter
Cheers,
Vadim.
no more pmtimer reads. i can now almost fully utililizy a 1GBit
interface with a file transfer while there was not one
cpu core fully utilized as observed with pmtimer. some live migration
tests revealed that it did not crash even under load.
@vadim: i think we need a proper patch for the others to test this ;-)
what i observed: is it right, that HV_X64_MSR_TIME_REF_COUNT is missing
in msrs_to_save[] in x86/x86.c of the kernel module?
thanks for you help,
peter
--
Gleb.
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