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

To: MaoXiaoyun <tinnycloud@xxxxxxxxxxx>, xen devel <xen-devel@xxxxxxxxxxxxxxxxxxx>
Subject: RE: [Xen-devel] Too much VCPUS makes domU high CPU utiliazation
From: "Tian, Kevin" <kevin.tian@xxxxxxxxx>
Date: Sun, 22 May 2011 10:05:11 +0800
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Thread-topic: [Xen-devel] Too much VCPUS makes domU high CPU utiliazation
>From: MaoXiaoyun [mailto:tinnycloud@xxxxxxxxxxx] 
>Sent: Friday, May 20, 2011 11:52 PM
>> >Another strang thing is seems all VCPUS of domainUA, are running only on 
>> >even number Physicals CPUS(that is 0, 2,4...),
>> >where explains where CPU Util is 800%.  But I don't understand whether this 
>> >is designed to. 
>> Are there any hard limitation you added from the configuration file? Or do 
>> you
>> observe this weird affinity all the time or occasionally? It looks strange 
>> to me
>> that scheduler will consistently keep such affinity if you don't assign it 
>> explicitly.
>In fact I have twn machine for test, M1 and M2, for now, the issue only show 
>I think I have no special configuration.After I compare the "xm info" of M1 
>and M2, I found
>that M1 has two nr_nodes while M2 only have one.
>This may explain where either all DomUA VCPUS all on even number of Physical 
> And also, this might cause guest slow booting.
>What do u think of this?

do you enable NUMA on M1, which may be the reason for the affinity? Could you 
post the
cpu topology of M1 which may prove this point?


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