[RFC PATCH 1/1] perf arm64: Implement --topdown with metrics

[John Garry]

>> In addition we could also add a --topdown arg to force using JSON 
>> metricgroups.
>>
> 
> What arg do think would be supplied?

something like -json or -metricgroup, meaning "Use pmu-events metric 
events to calculate topdown results rather than kernel CPU PMU events. 
This is default fallback if the kernel CPU PMU does not support topdown 
events"

> 
>> Did you actually test this patch? I have something experimental 
>> working from some time ago, and it was more complicated than this. I 
>> need to check the code again...
>>
> 
> I got stats back from this implementation, yes.  Let me know if there's 
> things my patch isn't catering for.

I'll give it a spin...

Thanks,
John