Messages in this thread | | | Date | Wed, 13 Dec 2017 11:18:07 +0100 | From | Jiri Olsa <> | Subject | Re: [RFC] Sharing PMU counters across compatible events |
| |
On Mon, Dec 11, 2017 at 07:34:49AM -0800, Tejun Heo wrote: > Hello, Jiri. > > On Wed, Dec 06, 2017 at 12:42:04PM +0100, Jiri Olsa wrote: > > I see this rather on the hw level, since it concerns HW counters > > > > I think we could detect same (alias) events at the time counters > > are added/removed on/from the cpu and share their HW part like > > counter idx, regs and such (struct hw_perf_event_cpu in my changes) > > > > this way it'd be completely transparent for generic code > > I don't quite follow why doing this in arch code is better than > generic. Doing this in arch means we'd need to do the same thing > multiple times for different archs. Why is that better?
so I can see this to be useful for HW conters only, because of limited number of regs
as for the higher level on which this could be implemented I see some pitfals with event rotations as Peter mentioned and task/cpu contexts scheduling.. while the hw-level implementation seems pretty straight forward
I'll test the code and let's see ;-)
jirka
| |