Re: [RFC/PATCHSET 00/19] perf stat: Cleanup counter aggregation (v1)

[Namhyung Kim]

Hi Andi,

On Mon, Oct 10, 2022 at 5:25 PM Andi Kleen <ak@xxxxxxxxxxxxxxx> wrote:
>
>
> On 10/10/2022 10:35 PM, Namhyung Kim wrote:
> > Hello,
> >
> > Current perf stat code is somewhat hard to follow since it handles
> > many combinations of PMUs/events for given display and aggregation
> > options.  This is my attempt to clean it up a little. ;-)
>
>
> My main concern would be subtle regressions since there are so many
> different combinations and way to travel through the code, and a lot of
> things are not covered by unit tests. When I worked on the code it was
> difficult to keep it all working. I assume you have some way to
> enumerate them all and tested that the output is identical?

Right, that's my concern too.

I have tested many combinations manually and checked if they
produced similar results.  But the problem is that I cannot test
all hardwares and more importantly it's hard to check
programmatically if the output is the same or not.  The numbers
vary on each run and sometimes it fluctuates a lot.  I don't have
good test workloads and the results work for every combination.

Any suggestions?

Thanks,
Namhyung