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[Xen-devel] Too much VCPUS makes domU high CPU utiliazation

To: xen devel <xen-devel@xxxxxxxxxxxxxxxxxxx>
Subject: [Xen-devel] Too much VCPUS makes domU high CPU utiliazation
From: MaoXiaoyun <tinnycloud@xxxxxxxxxxx>
Date: Thu, 19 May 2011 00:19:11 +0800
Cc: george.dunlap@xxxxxxxxxxxxx
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     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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