[Xen-devel] RE: Too much VCPUS makes domU high CPU utiliazation
> Subject: Re: Too much VCPUS makes domU high CPU utiliazation
> From: george.dunlap@xxxxxxxxxx
> To: tinnycloud@xxxxxxxxxxx
> CC: xen-devel@xxxxxxxxxxxxxxxxxxx; George.Dunlap@xxxxxxxxxxxxx
> Date: Thu, 19 May 2011 17:21:12 +0100
> This happens only during boot, is that right? It sounds like maybe
> Linux is trying to use some kind of barrier synchronization and failing
> because it's having a hard time getting all 16 vcpus to run at once. If
> that's the case, I think it's pretty much a Linux kernel issue; not sure
> what the hypervisor can do about it.
>From the test result, it is.
Are there some tools existed, and I can do some further analyze.
> On Wed, 2011-05-18 at 17:19 +0100, MaoXiaoyun wrote:
> > HI:
> > I have a host with 16 physical CPUS. Dom0 has 4 VCPUS.
> > When only start a domU-A(windows 2003 x86 64rc 2) with 16 VCPUS,
> > it starts quickly and eveything is fine.
> > But if I first start domU-B, which has 2VCPUS, domU-C 4VCPUS, and
> > domU-D 8 VCPUS, later I start DomUA again,
> > (so we have total 34 VCPUS, plus dom0), it will takes very long time
> > for domU-A to start ,and during the start, its CPU
> > utilizaiton is around 800% from xm top, after its start, it response
> > very slow in VNC, ans CPU utiliazation keeps high.
> > And right after I destoy other 3 domUs, domUA CPU drops to normal.
> > It might relate to CPU schedule, btw, my xen is 4.0.1.
> > Any comments?
> > <
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