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. > > -- > Gleb. -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
