Il giorno mar, 15/12/2009 alle 12.46 -0600, Justin M. Forbes ha scritto:

On Tue, 2009-12-15 at 19:31 +0100, Dario Lesca wrote:

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Il giorno mar, 15/12/2009 alle 11.28 -0600, Justin M. Forbes ha scritto:

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Is this normal?

KSM has a penalty in that it requires CPU cycles to scan for usable pages.

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This should be mitigated by the ksm service turning the scanner off when it is not needed. Do you have any more information on the hardware profile? Is there a smolt profile for this system?

Yes : http://www.smolts.org/client/show_all/pub_9da3c016-41da-42f1-b2c3-05f31ffb88...

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It's possible do something to improve the situation?

Is the ksmtuned service running?

Yes: [root@lesca ~]# /etc/init.d/ksmtuned status ksmtuned (pid 1522) in esecuzione...

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If not, please turn it on. Optionally you can also turn off ksm and ksmtuned.

I have turn off ksm and ksmtuned but the qemu use always 15% cpu... none is changed.

This is most likely an manifestation of https://bugzilla.redhat.com/show_bug.cgi?id=478317 and hopefully we will have a fix soon.

OK, I'll wait!

thanks!

thanks Justin