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 -- 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
