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-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. I think Vadim refers to this HV MSR http://msdn.microsoft.com/en-us/library/windows/hardware/ff542633%28v=vs.85%29.aspx -- 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
