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Date: Thu, 12 Jan 2017 10:11:37 +0000
From: Mark Rutland <mark.rutland@arm.com>
To: "Liang, Kan" <kan.liang@intel.com>
Cc: David Carrillo-Cisneros <davidcc@google.com>,
        Peter Zijlstra <peterz@infradead.org>,
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        Arnaldo Carvalho de Melo <acme@kernel.org>,
        Vince Weaver <vince@deater.net>, Paul Turner <pjt@google.com>,
        Stephane Eranian <eranian@google.com>
Subject: Re: [RFC 3/6] perf/core: use rb-tree to sched in event groups
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On Wed, Jan 11, 2017 at 08:31:11PM +0000, Liang, Kan wrote:

> > Kan, in your per-cpu event list patch you mentioned that you saw a large
> > overhead in perf_iterate_ctx() when skipping events for other CPUs.
> > Which callers of perf_iterate_ctx() specifically was that problematic for? Do
> > those callers only care about the *active* events, for example?
> 
> Based on my test, the large overhead was observed in perf_iterate_sb.
> Yes, it only cares about the *active* events.

Great!

That should mean the first patch of this series (adding the active
events lists) should give us sufficient infrastructure to solve that
particular issue.

Thanks,
Mark.