2023-12-05 07:14:41

by Athira Rajeev

[permalink] [raw]
Subject: Re: [PATCH] perf vendor events: Update datasource event name to fix duplicate events



> On 05-Dec-2023, at 1:42 AM, Ian Rogers <[email protected]> wrote:
>
> On Thu, Nov 23, 2023 at 8:01 AM Athira Rajeev
> <[email protected]> wrote:
>>
>> Running "perf list" on powerpc fails with segfault
>> as below:
>>
>> ./perf list
>> Segmentation fault (core dumped)
>>
>> 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)
>>
>> 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.
>>
>> 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.
>>
>> Fixes: fc1435807533 ("perf vendor events power10: Update JSON/events")
>> Signed-off-by: Athira Rajeev <[email protected]>
>
> Given duplicate events creates broken pmu-events.c we should capture
> that as an exception in jevents.py. That way a JEVENTS_ARCH=all build
> will fail if any vendor/architecture would break in this way. We
> should also add JEVENTS_ARCH=all to tools/perf/tests/make. Athira, do
> you want to look at doing this?
>
> Thanks,
> Ian

Hi Ian,

That’s a great suggestion. This will definitely help to capture the issues ahead.
I am interested and will work on adding this as part of tools/perf/tests/make

Thanks
Athira
>
>> ---
>> .../arch/powerpc/power10/datasource.json | 18 ++++++++++++++----
>> 1 file changed, 14 insertions(+), 4 deletions(-)
>>
>> diff --git a/tools/perf/pmu-events/arch/powerpc/power10/datasource.json b/tools/perf/pmu-events/arch/powerpc/power10/datasource.json
>> index 6b0356f2d301..0eeaaf1a95b8 100644
>> --- a/tools/perf/pmu-events/arch/powerpc/power10/datasource.json
>> +++ b/tools/perf/pmu-events/arch/powerpc/power10/datasource.json
>> @@ -99,6 +99,11 @@
>> "EventName": "PM_INST_FROM_L2MISS",
>> "BriefDescription": "The processor's instruction cache was reloaded from a source beyond the local core's L2 due to a demand miss."
>> },
>> + {
>> + "EventCode": "0x0003C0000000C040",
>> + "EventName": "PM_DATA_FROM_L2MISS_DSRC",
>> + "BriefDescription": "The processor's L1 data cache was reloaded from a source beyond the local core's L2 due to a demand miss."
>> + },
>> {
>> "EventCode": "0x000380000010C040",
>> "EventName": "PM_INST_FROM_L2MISS_ALL",
>> @@ -161,9 +166,14 @@
>> },
>> {
>> "EventCode": "0x000780000000C040",
>> - "EventName": "PM_INST_FROM_L3MISS",
>> + "EventName": "PM_INST_FROM_L3MISS_DSRC",
>> "BriefDescription": "The processor's instruction cache was reloaded from beyond the local core's L3 due to a demand miss."
>> },
>> + {
>> + "EventCode": "0x0007C0000000C040",
>> + "EventName": "PM_DATA_FROM_L3MISS_DSRC",
>> + "BriefDescription": "The processor's L1 data cache was reloaded from beyond the local core's L3 due to a demand miss."
>> + },
>> {
>> "EventCode": "0x000780000010C040",
>> "EventName": "PM_INST_FROM_L3MISS_ALL",
>> @@ -981,7 +991,7 @@
>> },
>> {
>> "EventCode": "0x0003C0000000C142",
>> - "EventName": "PM_MRK_DATA_FROM_L2MISS",
>> + "EventName": "PM_MRK_DATA_FROM_L2MISS_DSRC",
>> "BriefDescription": "The processor's L1 data cache was reloaded from a source beyond the local core's L2 due to a demand miss for a marked instruction."
>> },
>> {
>> @@ -1046,12 +1056,12 @@
>> },
>> {
>> "EventCode": "0x000780000000C142",
>> - "EventName": "PM_MRK_INST_FROM_L3MISS",
>> + "EventName": "PM_MRK_INST_FROM_L3MISS_DSRC",
>> "BriefDescription": "The processor's instruction cache was reloaded from beyond the local core's L3 due to a demand miss for a marked instruction."
>> },
>> {
>> "EventCode": "0x0007C0000000C142",
>> - "EventName": "PM_MRK_DATA_FROM_L3MISS",
>> + "EventName": "PM_MRK_DATA_FROM_L3MISS_DSRC",
>> "BriefDescription": "The processor's L1 data cache was reloaded from beyond the local core's L3 due to a demand miss for a marked instruction."
>> },
>> {
>> --
>> 2.39.3