Messages in this thread | | | Subject | Re: [RFC][PATCH 2/6] perf, arch: Rework perf_event_index() | From | Peter Zijlstra <> | Date | Mon, 21 Nov 2011 21:35:55 +0100 |
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On Mon, 2011-11-21 at 20:31 +0000, Will Deacon wrote: > On Mon, Nov 21, 2011 at 07:18:10PM +0000, Peter Zijlstra wrote: > > But does ARM have a read PMU counter from userspace > > instruction/capability? > > In ARMv7, you can enable user access to the performance counters but the > access is R/W so I don't think it's something we want to do (could interfere > with another task doing system-wide profiling).
Yeah, write access is pushing it a bit..
> > Lacking that its all moot of course. If it does, it would be nice to > > have an ARM version of patch 6. > > Well we'd need a way to get around the all-or-nothing user access to the PMU > and also the fact that we don't always have a user-readable clocksource. > > Either way, the event counters are indexed from 0 on ARMv7 so we should > use perf_event_idx_default.
Ok, done. Thanks!
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