> On 05-Feb-2021, at 8:21 PM, Liang, Kan <kan.li...@linux.intel.com> wrote:
>
>
>
> On 2/5/2021 7:55 AM, Athira Rajeev wrote:
>>>> Because in other archs, the var2_w of ‘perf_sample_weight’ could be used
>>>> to capture something else than the Local INSTR Latency.
>>>> Can we have some weak function to populate the header string ?
>>> I agree that the var2_w has different meanings among architectures. We
>>> should not force it to data->ins_lat.
>>>
>>> The patch as below should fix it. Does it work for you?
>> My point about weak function was actually for the arch specific header
>> string. But I guess we should not force it to data->ins_lat
>
> Yes, I don't think PowerPC should force var2_w to data->ins_lat. I think you
> can create your own field.
>
>> as you mentioned. I checked the below patch defining an
>> ‘arch_perf_parse_sample_weight' for powerpc and it works.
>> But one observation is that, for cases with kernel having support for
>> PERF_SAMPLE_WEIGHT_STRUCT but missing arch specific support for
>> ‘arch_perf_parse_sample_weight', it will report ‘Local Weight’ wrongly since
>> weak function takes it as 64 bit. Not sure if that is a valid case to
>> consider though.
>
> Currently, the PERF_SAMPLE_WEIGHT_STRUCT is only enabled on X86 by default.
> https://lore.kernel.org/lkml/1612296553-21962-6-git-send-email-kan.li...@linux.intel.com/
>
> For PowerPC, the PERF_SAMPLE_WEIGHT is still the default setting. There is no
> way to set PERF_SAMPLE_WEIGHT_STRUCT via perf tool.
> I don't think the above case will happen.
Yes.
I tested with kernel changes from perf/core branch of
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git
And perf tools side changes from tmp.perf/core branch of
git://git.kernel.org/pub/scm/linux/kernel/git/acme/linux.git along with the
above change.
The default setting for powerpc works with out breaking anything and verified
using “perf mem record <workload>”
Tested-by: Athira Rajeev <atraj...@linux.vnet.ibm.com>
Thanks
Athira Rajeev
>
> Thanks,
> Kan
