Re: [PATCH 2/3] Revert 'perf evlist: Fix creation of cpu map'

From: Arnaldo Carvalho de Melo
Date: Wed May 16 2012 - 11:26:22 EST


Em Wed, May 16, 2012 at 06:45:48PM +0900, Namhyung Kim escreveu:
> The commit 55261f46702c ("perf evlist: Fix creation of cpu
> map") changed to create a per-task event when no cpu target
> is specified. However it caused a problem since perf-task do
> not allow event inheritance due to scalability issues so
> that the result will contain samples only from parent, not
> from its children.
>
> So we should use perf-task-per-cpu events anyway to get the
> right result. Revert it.
>
> Reported-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
> Analysed-by: Ingo Molnar <mingo@xxxxxxxxxx>
> Acked-and-tested-by: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>

I'm applying it, but while trying to figure out if the logic was right I
tried:

perf top -C 0 -u acme

To check what is that this user is doing on that CPU, and its not
possible :-\

UID switch overriding CPU!

- Arnaldo
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