linux-kernel - Re: [RFC][PATCH] perf: Rewrite enabled/running timekeeping

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Message-ID: <20170905111943.v2twm3jgu3mct3ib@hirez.programming.kicks-ass.net>
Date:   Tue, 5 Sep 2017 13:19:43 +0200
From:   Peter Zijlstra <peterz@...radead.org>
To:     Alexey Budankov <alexey.budankov@...ux.intel.com>
Cc:     Ingo Molnar <mingo@...hat.com>,
        Arnaldo Carvalho de Melo <acme@...nel.org>,
        Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
        Andi Kleen <ak@...ux.intel.com>,
        Kan Liang <kan.liang@...el.com>,
        Dmitri Prokhorov <Dmitry.Prohorov@...el.com>,
        Valery Cherepennikov <valery.cherepennikov@...el.com>,
        Mark Rutland <mark.rutland@....com>,
        Stephane Eranian <eranian@...gle.com>,
        David Carrillo-Cisneros <davidcc@...gle.com>,
        linux-kernel <linux-kernel@...r.kernel.org>,
        Vince Weaver <vince@...ter.net>,
        Thomas Gleixner <tglx@...utronix.de>
Subject: Re: [RFC][PATCH] perf: Rewrite enabled/running timekeeping

On Tue, Sep 05, 2017 at 01:17:39PM +0300, Alexey Budankov wrote:
> However we can't completely get rid of whole tree iterations because of 
> inheritance code on forks in perf_event_init_context() here:

Right, fork() / inherit needs to iterate the full thing, nothing to be
done about that.

I'll go make proper patches for that timekeeping rewrite and then have a
look at your patches.