From: Nazar Kazakov <nazar.kazakov@codethink.co.uk>
To: Ian Rogers <irogers@google.com>
Cc: Peter Zijlstra <peterz@infradead.org>,
Ingo Molnar <mingo@redhat.com>,
Arnaldo Carvalho de Melo <acme@kernel.org>,
Namhyung Kim <namhyung@kernel.org>,
Mark Rutland <mark.rutland@arm.com>,
Alexander Shishkin <alexander.shishkin@linux.intel.com>,
Jiri Olsa <jolsa@kernel.org>,
Adrian Hunter <adrian.hunter@intel.com>,
James Clark <james.clark@linaro.org>,
linux-perf-users@vger.kernel.org, linux-kernel@vger.kernel.org,
Ben Dooks <ben.dooks@codethink.co.uk>
Subject: Re: [PATCH] perf jevents: make events order more deterministic
Date: Mon, 06 Jul 2026 19:22:49 +0100 [thread overview]
Message-ID: <9871da36895a05e0ca5646ba6edf4a52@codethink.co.uk> (raw)
In-Reply-To: <CAP-5=fWXhESb=4TMyt2X9oM64h5xwpNf7VGqXCs+NbPr8zeuGA@mail.gmail.com>
On 2026-07-06 19:04, Ian Rogers wrote:
> On Mon, Jul 6, 2026 at 10:57 AM Nazar Kazakov
> <nazar.kazakov@codethink.co.uk> wrote:
>>
>> Some of the events have the same name, but differing descriptions.
>> This
>> leads to a non-deterministic sorting order, so fix by adding the
>> description field to the order.
>>
>> Signed-off-by: Nazar Kazakov <nazar.kazakov@codethink.co.uk>
>
> This shouldn't be an issue; can you give an example? I mean, with:
> $ perf stat -e event1,event1 true
> There's only one meaning for what event1 is. There is wildcard
> support, but that's not the same as having the same event more than
> once, differing only by description. Note, I deliberately use events
> with perf stat in the example because the metrics build on the regular
> event parsing code.
I meant sorting order during build time:
tools/perf/pmu-events/pmu-events.c
changes between different builds, you can see an example of diffoscope
output here
https://freedesktop-sdk.gitlab.io/-/freedesktop-sdk/-/jobs/15174060131/artifacts/result_folder/components/perf.bst/index.html
/* offset=5995059 */
"lpm_l2_rfo_misses\000lpm_l2;lpm_l2_rfo\000d_ratio(L2_RQSTS.RFO_MISS,
duration_time)\000\000L2 cache request for ownership (RFO) misses per
second\000\0001misses/s\000\000\000\000000"
/* offset=5995210 */
"lpm_l2_rfo_misses\000lpm_l2;lpm_l2_rfo\000d_ratio(L2_RQSTS.RFO_MISS,
L2_RQSTS.RFO_HIT + L2_RQSTS.RFO_MISS)\000\000L2 cache request for
ownership (RFO) misses\000\000100%\000\000\000\000000"
vs
/* offset=5995059 */
"lpm_l2_rfo_misses\000lpm_l2;lpm_l2_rfo\000d_ratio(L2_RQSTS.RFO_MISS,
L2_RQSTS.RFO_HIT + L2_RQSTS.RFO_MISS)\000\000L2 cache request for
ownership (RFO) misses\000\000100%\000\000\000\000000"
/* offset=5995217 */
"lpm_l2_rfo_misses\000lpm_l2;lpm_l2_rfo\000d_ratio(L2_RQSTS.RFO_MISS,
duration_time)\000\000L2 cache request for ownership (RFO) misses per
second\000\0001misses/s\000\000\000\000000"
That leads to non-reproducible binaries, even though the functionality
is probably the same.
Thanks,
Nazar Kazakov
next prev parent reply other threads:[~2026-07-06 18:23 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-07-06 17:56 [PATCH] perf jevents: make events order more deterministic Nazar Kazakov
2026-07-06 18:04 ` Ian Rogers
2026-07-06 18:22 ` Nazar Kazakov [this message]
2026-07-06 18:48 ` Ian Rogers
2026-07-06 19:08 ` Nazar Kazakov
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