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

[Disha Goel <disgoel@linux.ibm.com>]

On 23/11/23 9:31 pm, Athira Rajeev 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 <atrajeev@linux.vnet.ibm.com>

I have tested the patch on Power10 machine. Perf list works correctly without any segfault now.

	# ./perf list

	List of pre-defined events (to be used in -e or -M):

	  branch-instructions OR branches                    [Hardware event]
	  branch-misses                                      [Hardware event]

Tested-by: Disha Goel <disgoel@linux.ibm.com>

> ---
>   .../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."
>     },
>     {