Re: [PATCH 1/2] perf vendor events arm64: AmpereOne/AmpereOneX: Mark LD_RETIRED impacted by errata

Ilkka Koskinen
2025-03-20T20:10:18Z

Hi James,

On Tue, 18 Mar 2025, James Clark wrote:
> On 13/03/2025 8:15 pm, Ilkka Koskinen wrote:
>> Atomic instructions are both memory-reading and memory-writing
>> instructions and so should be counted by both LD_RETIRED and ST_RETIRED
>> performance monitoring events. However LD_RETIRED does not count atomic
>> instructions.
>>
>> Signed-off-by: Ilkka Koskinen <ilkka@os.amperecomputing.com>
>> ---
>> tools/perf/pmu-events/arch/arm64/ampere/ampereone/memory.json | 4 +++-
>> .../perf/pmu-events/arch/arm64/ampere/ampereonex/memory.json | 4 +++-
>> 2 files changed, 6 insertions(+), 2 deletions(-)
>>
>> diff --git a/tools/perf/pmu-events/arch/arm64/ampere/ampereone/memory.json
>> b/tools/perf/pmu-events/arch/arm64/ampere/ampereone/memory.json
>> index 0711782bfa6b..13382d29b25f 100644
>> --- a/tools/perf/pmu-events/arch/arm64/ampere/ampereone/memory.json
>> +++ b/tools/perf/pmu-events/arch/arm64/ampere/ampereone/memory.json
>> @@ -1,6 +1,8 @@
>> [
>> {
>> - "ArchStdEvent": "LD_RETIRED"
>> + "ArchStdEvent": "LD_RETIRED",
>> + "Errata": "Errata AC03_CPU_52",
>> + "BriefDescription": "Instruction architecturally executed,
>> condition code check pass, load. Impacted by errata -"
>
> I think this could also have a 'Fixes:' tag, either way:
>
> Reviewed-by: James Clark <james.clark@linaro.org>

Yeah, that's true. I guess, I was thinking about using 'Fixes' more on
broken patches rather than when adding a patch dealing with a new hw
errata. Well, given you're find with this, I don't think I'll resubmit it
with a Fixes tag this time.

Cheers, Ilkka