On Tuesday, March 27, 2012 05:58:01 PM Peter Lieven wrote: > On 27.03.2012 17:44, Vadim Rozenfeld wrote: > > On Tuesday, March 27, 2012 04:06:13 PM Peter Lieven wrote: > >> On 27.03.2012 14:29, Gleb Natapov wrote: > >>> On Tue, Mar 27, 2012 at 02:28:04PM +0200, Peter Lieven wrote: > >>>> On 27.03.2012 14:26, Gleb Natapov wrote: > >>>>> 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- > >>>>>>>>>>>>>>>>>>>>>> 1v cpu-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/ff5 > >>>>>>>>>>>>>> 42 633%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. > >>>> > >>>> ok, so it would be interesting if it helps to avoid the pmtimer reads > >>>> we observed earlier. right? > >>> > >>> Yes. > >> > >> first feedback: performance seems to be amazing. i cannot confirm that > >> it breaks hv_spinlocks, hv_vapic and hv_relaxed. > >> why did you assume this? > > > > I didn't mean that hv_refcnt will break any other hyper-v features. > > I just want to say that turning hv_refcnt on (as any other hv_ option) > > will crash Win8 on boot-up. > > yes, i got it meanwhile ;-) > > let me know what you think should be done to further test > the refcnt implementation. > > i would suggest to return at least 0xFFFFFFFF if msr 0x40000021 > is read. IIRC Win7(W2k8R2) only reads this MSR. Win8 reads and writes. > > peter > > > Cheers, > > Vadim. > > > >> no more pmtimer reads. i can now almost fully utililizy a 1GBit > >> interface with a file transfer while there was not one > >> cpu core fully utilized as observed with pmtimer. some live migration > >> tests revealed that it did not crash even under load. > >> > >> @vadim: i think we need a proper patch for the others to test this ;-) > >> > >> what i observed: is it right, that HV_X64_MSR_TIME_REF_COUNT is missing > >> in msrs_to_save[] in x86/x86.c of the kernel module? > >> > >> thanks for you help, > >> peter > >> > >>> -- > >>> > >>> 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
