Re: [PATCH] perf top: Use evsel's cpus to replace user_requested_cpus

Namhyung Kim
2023-12-12T17:23:19Z

On Tue, Dec 12, 2023 at 7:56 AM Liang, Kan <kan.liang@linux.intel.com> wrote:
>
>
>
> On 2023-12-11 4:13 p.m., Arnaldo Carvalho de Melo wrote:
> > Em Fri, Dec 08, 2023 at 01:08:55PM -0800, kan.liang@linux.intel.com escreveu:
> >> From: Kan Liang <kan.liang@linux.intel.com>
> >>
> >> perf top errors out on a hybrid machine
> >> $perf top
> >>
> >> Error:
> >> The cycles:P event is not supported.
> >>
> >> The user_requested_cpus may contain CPUs that are invalid for a hybrid
> >> PMU. It causes perf_event_open to fail.
> >
> > ?
> >
> > All perf top expects is that the "cycles", the most basic one, be
> > collected, on all CPUs in the system.
> >
>
> Yes, but for hybrid there is no single "cycles" event which can cover
> all CPUs.

Does that mean the kernel would reject the legacy "cycles" event
on hybrid CPUs?

Thanks,
Namhyung