Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
Date:   Wed, 20 Mar 2019 14:14:32 +0100
From:   Peter Zijlstra <peterz@infradead.org>
To:     Stephane Eranian <eranian@google.com>
Cc:     Ingo Molnar <mingo@kernel.org>, Jiri Olsa <jolsa@redhat.com>,
        LKML <linux-kernel@vger.kernel.org>, tonyj@suse.com,
        nelson.dsouza@intel.com
Subject: Re: [RFC][PATCH 4/8] perf/x86: Remove PERF_X86_EVENT_COMMITTED
Message-ID: <20190320131432.GK6521@hirez.programming.kicks-ass.net>
References: <20190314130113.919278615@infradead.org>
 <20190314130705.750219024@infradead.org>
 <CABPqkBQr4VbNQG9R9j8Di=6fSziUw1s_QLyE9L7nsMTdWd8GtQ@mail.gmail.com>
 <20190319210018.GP5996@hirez.programming.kicks-ass.net>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <20190319210018.GP5996@hirez.programming.kicks-ass.net>
User-Agent: Mutt/1.10.1 (2018-07-13)
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

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@infradead.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 :-)