Re: [PATCH] expose per-vm statistics via debugfs

[Avi Kivity <avi@redhat.com>]

On 08/19/2009 03:53 PM, Ryota Ozaki wrote:
> Hi,
>
> This patch let kvm exposes per-vm statistics about
> such as the total number of vm exits, via debugfs.
>
> Existing kvm already collects the per-vm statistics,
> but it has no interface to expose them to users.
> This patch creates directories named a pid of the
> corresponding vm in debugfs of kvm, containing the
> same files that original debugfs exposes.
>
> The per-vm statistics are useful to know activities
> of vms (and to identify anomalous vms for example)
> with more detailed information than cpu and memory
> usage, and network traffics. And also the patch
> introduces no performance overhead, thus, it should
> be familiar with online operations, e.g., dynamic
> adaptation of assigning vm resources using the
> statistics.
>
> Note that this patch requires a trivial modification
> to kvm_stat script. Once this patch is accepted I will
> send a patch for it.
>
> Thanks,
>    ozaki-r
>
>    

My plan is to completely remove the current statistics in favour of 
tracepoints.  You can already display tracepoint statistics with 'perf 
stat' (see tools/perf); tracepoints have the advantage that they can be 
completely disabled at runtime and thus have no performance impact.

-- 
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