Re: [PATCH 1/6] perf/core: Provide a kernel-internal interface to get to performance counters

Arjan van de Ven
2009-11-02T05:37:32Z

On Mon, 2 Nov 2009 14:46:55 +1100
Paul Mackerras <paulus@samba.org> wrote:

> Frederic Weisbecker writes:
>
> > /*
> > + * perf_event_create_kernel_counter
> > + * MUST be called from a kernel thread.
>
> Why? The reason for this requirement isn't obvious to me. It would
> be good to have the reason documented in the comment for the sake of
> people modifying the code in future.

because if you call it from another context it will attach to that
context... and go away when that context goes away...

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Arjan van de Ven Intel Open Source Technology Centre
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