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. -- 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
