Re: [PATCH V7 07/14] perf/core: Add a new PERF_EV_CAP_COEXIST event capability

From: Peter Zijlstra
Date: Fri Jul 24 2020 - 10:51:50 EST

On Fri, Jul 24, 2020 at 07:39:08AM -0700, Andi Kleen wrote:
> > The consequence is that SLOTS must be the leader, is that really a
> > problem? You keep providing the {cycles, slots, metric-things} example,
> Yes that's a problem. One (major) use case for topdown is to
> sample on lots of different events, but always create groups that
> also measure topdown metrics for that sampling period. For that we need
> other leaders.

Apparently the only problem here is the tool, the kernel doesn't care
which events in a group are sampling, there could be multiple.