linux-kernel - Re: [RFC][PATCH 4/8] perf/x86: Remove PERF_X86_EVENT

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Date:   Wed, 20 Mar 2019 14:14:32 +0100
From:   Peter Zijlstra <peterz@...radead.org>
To:     Stephane Eranian <eranian@...gle.com>
Cc:     Ingo Molnar <mingo@...nel.org>, Jiri Olsa <jolsa@...hat.com>,
        LKML <linux-kernel@...r.kernel.org>, tonyj@...e.com,
        nelson.dsouza@...el.com
Subject: Re: [RFC][PATCH 4/8] perf/x86: Remove PERF_X86_EVENT_COMMITTED

On Tue, Mar 19, 2019 at 10:00:18PM +0100, Peter Zijlstra wrote:
> On Tue, Mar 19, 2019 at 01:48:18PM -0700, Stephane Eranian wrote:
> > On Thu, Mar 14, 2019 at 6:11 AM Peter Zijlstra <peterz@...radead.org> wrote:
> > 
> > > For x86_pmu_commit_txn(), cpuc->n_events is updated, but we can
> > > trivially compute the desired value with cpuc->n_txn -- the number of
> > > events added in this transaction.
> > >
> > I suggest you put this explanation in the code so that it is easier to
> > understand.
> 
> Right, I actually attempted writing that comment a few times but every
> time it became a mess. I'll try again, because you're quite right, this
> is a bit magical.

Ha! I found the comment, it's in patch 8 :-)