Re: [PATCH 3/6] 2.6.16-rc1 perfmon2 patch for review

From: Bryan O'Sullivan
Date: Thu Jan 26 2006 - 13:21:35 EST


On Wed, 2006-01-25 at 21:43 -0800, Stephane Eranian wrote:

> This one contains statistics about perfmon such as PMU model, number of active
> sessions, and also a bunch of per-cpu statistics (see attached file).
>
> $ cat /proc/perfmon
> perfmon version : 2.2
> PMU model : Intel Pentium M
> PMU description version : 1.0
> counter width : 31
> loaded per-thread sessions : 0
> loaded sys-wide sessions : 0
> current smpl buffer memory : 0
> format : d1-39-b2-9e-62-e8-40-e4-b4-02-73-07-87-92-e9-37 default_format2
> CPU0 total ovfl intrs : 0
> CPU0 spurious intrs : 0
> CPU0 replay intrs : 0
> CPU0 regular intrs : 0
> CPU0 overflow cycles : 0
> CPU0 overflow phase1 : 0
> CPU0 overflow phase2 : 0
> CPU0 overflow phase3 : 0
> CPU0 smpl handler calls : 0
> CPU0 smpl handler cycles : 0
> CPU0 set switch count : 0
> CPU0 set switch cycles : 0
> CPU0 handle timeout : 0
> CPU0 owner task : -1
> CPU0 owner context : 00000000
> CPU0 activations : 0

Is there any reason you might need those per-CPU statistics in an atomic
snapshot form? That seems unlikely, off the top of my head. You could
either have a per-CPU directory with a file for each counter, which
seems cleanest, or a per-CPU file with all counters and the name of
each, although the format wants cleaning compared to what you have now.

<b

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