From mboxrd@z Thu Jan  1 00:00:00 1970
From: George Dunlap <george.dunlap@eu.citrix.com>
Subject: Re: VCPU migration overhead conpensation ?
Date: Wed, 10 Apr 2013 09:21:17 +0100
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To: Sisu Xi <xisisu@gmail.com>
Cc: Dario Faggioli <dario.faggioli@citrix.com>, "xen-devel@lists.xensource.com" <xen-devel@lists.xensource.com>
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(BTW, please don't top-post on xen-devel: respond in-line to the thing 
you want to respond to.)

On 10/04/13 06:44, Sisu Xi wrote:
> Hi, Dario:
>
> Thanks for your reply and tips for sending emails!  :)
>
> I am also performing some overhead measurement for the scheduler. If a 
> VCPU is migrated from one core to another, the overhead is around 2 
> microseconds on my machine, which is much less than what is set in 
> Credit2 (50 microseconds).

When you say "overhead", I assume you mean that's how long the whole 
migration takes?

The point of the compensation isn't so much for the actual migration 
itself, but for the lower performance the vcpu will get after the 
migration due to having cold caches.

  -George