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.
Thanks,
Kan
