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-cpu.txt.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.
Best regards,
Vadim.
>
> Peter
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