Re: [PATCH 14/15] perf stat: Rename "aggregate-number" to "cpu-count" in JSON

From: Namhyung Kim <namhyung@kernel.org>
To: Ian Rogers <irogers@google.com>,
	Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>, Ingo Molnar <mingo@kernel.org>,
	Peter Zijlstra <peterz@infradead.org>,
	LKML <linux-kernel@vger.kernel.org>,
	Adrian Hunter <adrian.hunter@intel.com>,
	linux-perf-users@vger.kernel.org,
	Kan Liang <kan.liang@linux.intel.com>,
	Zhengjun Xing <zhengjun.xing@linux.intel.com>,
	James Clark <james.clark@arm.com>,
	Athira Jajeev <atrajeev@linux.vnet.ibm.com>
Subject: Re: [PATCH 14/15] perf stat: Rename "aggregate-number" to "cpu-count" in JSON
Date: Tue, 29 Nov 2022 14:45:55 -0800	[thread overview]
Message-ID: <CAM9d7cj-JeKiHUM1Eq36937q+o+yj=DKwt_pYQLD6aC5zCTN+Q@mail.gmail.com> (raw)
In-Reply-To: <CAP-5=fWF7ScB0kHKQsqePHmg3sJf22TOfvKcNeYQdMoD0p8Tbg@mail.gmail.com>

On Sat, Nov 26, 2022 at 7:14 PM Ian Rogers <irogers@google.com> wrote:
>
> On Thu, Nov 24, 2022 at 11:51 PM Namhyung Kim <namhyung@kernel.org> wrote:
> >
> > Hi Ian,
> >
> > On Wed, Nov 23, 2022 at 3:31 PM Ian Rogers <irogers@google.com> wrote:
> > >
> > > On Wed, Nov 23, 2022 at 10:02 AM Namhyung Kim <namhyung@kernel.org> wrote:
> > > >
> > > > As the JSON output has been broken for a little while, I guess there are
> > > > not many users.  Let's rename the field to more intuitive one. :)
> > >
> > > I'm not sure cpu-count is accurate. For example, an uncore counter in
> > > a dual socket machine may have a CPU mask of "0, 36", ie one event per
> > > socket. The aggregate-number in this case I believe is 2.
> >
> > You're right.  In case of uncore events, it can be confusing.  But in some
> > sense it could be thought as cpu count as well since it aggregates the
> > result from two cpus anyway. :)
> >
> > Note that the aggregate-number (or cpu-count) is only printed if users
> > requested one of aggregation options like --per-socket or --per-core.
> > In your example, then it could print 1 for each socket.
> >
> > But I think uncore events are different from core events, and hopefully
> > they have separate instances for different sockets or something already.
> > That means it doesn't need to use those aggregation options for them.
> >
> > Also the CSV output uses "cpus" for the same information.  It'd be nice
> > we could have consistency.
>
> So in the original patch from Claire she'd passed the name "number"
> through to the json from the stat code. Having an integer called
> "number" isn't exactly intention revealing - thank you for your clean
> up work! :-) I switched "number" to be "aggregate number" as the
> number comes from the "data" aggregated and the code refers to it as
> aggregate data. I think aggregate-number is more consistent with the
> code, and cpu-count would look strange in the uncore case above where
> the number of CPUs (really hyperthreads) is 72. Perhaps we should also
> be outputting the aggregation mode with the number. Anyway, I think
> for the patch series I'd prefer we skipped this one and kept the rest.

Right, I think we need a more general term to include non-cpu events.
But it seems Arnaldo already merged it.

Arnaldo, do you want me to send a revert?

Thanks,
Namhyung