On Tuesday, March 27, 2012 11:26:29 AM 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? Gleb mentioned that it properly handled in upstream, otherwise just comment the entire HPET section in acpi-dsdt.dsl file. > > the stuff you send yesterday is for qemu, right? would > it be possible to use it in qemu-kvm also? Yes, but don't forget about kvm patch as well. > > peter > > >> -- > >> > >> Gleb. -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
