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Subject: Re: [PATCH] perf vendor events: Update datasource event name to fix
 duplicate events
From:   Athira Rajeev <atrajeev@linux.vnet.ibm.com>
In-Reply-To: <CAP-5=fXWm_ZZjQ-36eTJTuWQsQwwCEXer22Oid7X-PSe8=WY1Q@mail.gmail.com>
Date:   Tue, 5 Dec 2023 12:46:17 +0530
Cc:     Kajol Jain <kjain@linux.ibm.com>,
        Adrian Hunter <adrian.hunter@intel.com>,
        linux-perf-users <linux-perf-users@vger.kernel.org>,
        Madhavan Srinivasan <maddy@linux.ibm.com>,
        James Clark <james.clark@arm.com>,
        Jiri Olsa <jolsa@kernel.org>,
        Disha Goel <disgoel@linux.vnet.ibm.com>,
        linuxppc-dev <linuxppc-dev@lists.ozlabs.org>,
        LKML <linux-kernel@vger.kernel.org>
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Message-Id: <2400D325-80A3-4BA0-9467-03F452A72911@linux.vnet.ibm.com>
References: <20231123160110.94090-1-atrajeev@linux.vnet.ibm.com>
 <CAP-5=fWtLHCyZh_6hBkCg16ekOXfwSGAVT9xvgKcUsMcu=Ou9w@mail.gmail.com>
 <ZW40nstmGUeV9Fie@kernel.org> <ZW406O38z3DmVwOX@kernel.org>
 <CAP-5=fXWm_ZZjQ-36eTJTuWQsQwwCEXer22Oid7X-PSe8=WY1Q@mail.gmail.com>
To:     Ian Rogers <irogers@google.com>,
        Arnaldo Carvalho de Melo <acme@kernel.org>,
        Namhyung Kim <namhyung@kernel.org>
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> On 05-Dec-2023, at 2:43=E2=80=AFAM, Ian Rogers <irogers@google.com> =
wrote:
>=20
> On Mon, Dec 4, 2023 at 12:22=E2=80=AFPM Arnaldo Carvalho de Melo
> <acme@kernel.org> wrote:
>>=20
>> Em Mon, Dec 04, 2023 at 05:20:46PM -0300, Arnaldo Carvalho de Melo =
escreveu:
>>> Em Mon, Dec 04, 2023 at 12:12:54PM -0800, Ian Rogers escreveu:
>>>> On Thu, Nov 23, 2023 at 8:01=E2=80=AFAM Athira Rajeev
>>>> <atrajeev@linux.vnet.ibm.com> wrote:
>>>>>=20
>>>>> Running "perf list" on powerpc fails with segfault
>>>>> as below:
>>>>>=20
>>>>>   ./perf list
>>>>>   Segmentation fault (core dumped)
>>>>>=20
>>>>> This happens because of duplicate events in the json list.
>>>>> The powerpc Json event list contains some event with same
>>>>> event name, but different event code. They are:
>>>>> - PM_INST_FROM_L3MISS (Present in datasource and frontend)
>>>>> - PM_MRK_DATA_FROM_L2MISS (Present in datasource and marked)
>>>>> - PM_MRK_INST_FROM_L3MISS (Present in datasource and marked)
>>>>> - PM_MRK_DATA_FROM_L3MISS (Present in datasource and marked)
>>>>>=20
>>>>> pmu_events_table__num_events uses the value from
>>>>> table_pmu->num_entries which includes duplicate events as
>>>>> well. This causes issue during "perf list" and results in
>>>>> segmentation fault.
>>>>>=20
>>>>> Since both event codes are valid, append _DSRC to the Data
>>>>> Source events (datasource.json), so that they would have a
>>>>> unique name. Also add PM_DATA_FROM_L2MISS_DSRC and
>>>>> PM_DATA_FROM_L3MISS_DSRC events. With the fix, perf list
>>>>> works as expected.
>>>>>=20
>>>>> Fixes: fc1435807533 ("perf vendor events power10: Update =
JSON/events")
>>>>> Signed-off-by: Athira Rajeev <atrajeev@linux.vnet.ibm.com>
>>>>=20
>>>> Given duplicate events creates broken pmu-events.c we should =
capture
>>>> that as an exception in jevents.py. That way a JEVENTS_ARCH=3Dall =
build
>>>> will fail if any vendor/architecture would break in this way. We
>>>> should also add JEVENTS_ARCH=3Dall to tools/perf/tests/make. =
Athira, do
>>>> you want to look at doing this?
>>>=20
>>> Should I go ahead and remove this patch till this is sorted out?
>>=20
>> I'll keep it, its already in tmp.perf-tools-next, we can go from =
there
>> and improve this with follow up patches,

Thanks Arnaldo for pulling the fix patch.

>=20
> Agreed. I could look to do the follow up but likely won't have a
> chance for a while. If others could help out it would be great. I'd
> like to have the jevents and json be robust enough that we don't trip
> over problems like this and the somewhat similar AmpereOne issue.

Yes Ian.

I will look at adding this with follow up patches and including this as =
part of tools/perf/tests/make

Thanks
Athira
>=20
> Thanks,
> Ian
>=20
>> - Arnaldo