Re: [PATCH v3] perf: Store active software events in a hashlist

From: Peter Zijlstra
Date: Fri Apr 16 2010 - 06:53:36 EST


On Wed, 2010-04-14 at 02:53 +0200, Frederic Weisbecker wrote:
>
> Each time a software event triggers, we need to walk through
> the entire list of events from the current cpu and task contexts
> to retrieve a running perf event that matches.
> We also need to check a matching perf event is actually counting.
>
> This walk is wasteful and makes the event fast path scaling
> down with a growing number of events running on the same
> contexts.
>
> To solve this, we store the running perf events in a hashlist to
> get an immediate access to them against their type:event_id when
> they trigger.

Looks good, thanks Frederic!
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