On Wed, Oct 17, 2018 at 07:19:55PM +0200, Peter Zijlstra wrote: > On Wed, Oct 17, 2018 at 04:43:27PM +0000, Song Liu wrote: > > > > That makes task and cpu contexts wildly different, which will complicate > > > matters I feel. > > > > > > > I think we only need different logic when adding events to the task/cpu > > contexts. The ctx_sched_in() and ctx_sched_out() will need some extra > > logic to filter out events that are not being scheduled (don't schedule > > events on PMU-a when rotating PMU-b). This logic will be the same for > > task and cpu context. The difference is, the CPU context will not have > > such events, because we never added such event to CPU context. > > > > Does this make sense? I could try draft a RFC to see how difficult it is. > > I'm not sure it saves much, if we have multiple per-cpu contexts we get > to re-introduce the active_ctx_list and loose the simplification for the > online status. > > Plus that fundamental assymetry -- which would bother my OCD forever > more :-)
Worse, the whole syscall that installs the events will come apart. The locking for the two cases is different :/
