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. > peter > > > David. > >-- > >To unsubscribe from this list: send the line "unsubscribe kvm" in > >the body of a message to majord...@vger.kernel.org > >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 majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
