Re: [RFC 1/2] perf core: Add PERF_COUNT_SW_CGROUP_SWITCHES event

[Andi Kleen]

On Wed, Dec 02, 2020 at 11:47:25AM -0800, Stephane Eranian wrote:
> On Wed, Dec 2, 2020 at 11:28 AM Andi Kleen <ak@xxxxxxxxxxxxxxx> wrote:
> >
> > > +     prev_cgrp = task_css_check(prev, perf_event_cgrp_id, 1)->cgroup;
> > > +     next_cgrp = task_css_check(next, perf_event_cgrp_id, 1)->cgroup;
> > > +
> > > +     if (prev_cgrp != next_cgrp)
> > > +             perf_sw_event_sched(PERF_COUNT_SW_CGROUP_SWITCHES, 1, 0);
> >
> > Seems to be the perf cgroup only, not all cgroups.
> > That's a big difference and needs to be documented properly.
> >
> We care about the all-cgroup case.

Then it's not correct I think. You need a different hook point.

-Andi