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[Xen-devel] RE: Too much VCPUS makes domU high CPU utiliazation 
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 > 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.
 >
 > -George
 
 >From the test result, it is.
 Are there some tools existed, and I can do some further analyze.
 Thanks.
 
 >
 > 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?
 > >
 > > <
 BR>>
 >
 
 
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