Re: [PATCH RFC 0/3] Add guest cpu_entitlement reporting

From: Avi Kivity
Date: Mon Aug 27 2012 - 14:55:25 EST


On 08/23/2012 04:14 PM, Michael Wolf wrote:
> This is an RFC regarding the reporting of stealtime. In the case of
> where you have a system that is running with partial processors such as
> KVM the user may see steal time being reported in accounting tools such
> as top or vmstat. This can cause confusion for the end user. To
> ease the confusion this patch set adds a sysctl interface to set the
> cpu entitlement. This is the percentage of cpu that the guest system is
> expected to receive. As long as the steal time is within its expected
> range it will show up as 0 in /proc/stat. The user will then see in the
> accounting tools that they are getting a full utilization of the cpu
> resources assigned to them.
>
> This patchset is changing the contents/output of /proc/stat and could affect
> user tools. However the default setting is that the cpu is entitled to 100%
> so the code will act as before. Also another field could be added to the
> /proc/stat output and show the unaltered steal time. Since this additional
> field could cause more confusion than it would clear up I have left it out
> for now.
>

How would a guest know what its entitlement is?


--
I have a truly marvellous patch that fixes the bug which this
signature is too narrow to contain.

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