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. > > > peter > > > > > David. > > > > > >-- > > >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 > > -- > 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
