Messages in this thread | | | Date | Thu, 16 Jan 2014 18:31:10 +0100 | From | Peter Zijlstra <> | Subject | Re: [patch/rfc] perf on raspberry-pi without overflow interrupt |
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On Thu, Jan 16, 2014 at 12:13:10PM -0500, Vince Weaver wrote: > On Tue, 14 Jan 2014, Peter Zijlstra wrote: > > > On Mon, Jan 13, 2014 at 11:55:17PM -0500, Vince Weaver wrote: > > > > I don't see an existing pmu capabilities struct... or do you mean > > > coming up with one? > > > > Yeah, adding one. > > So would it be a struct, or just an integer with flags?
I hadn't really considered that; per the below proposed names I suppose I was thinking of 'unsigned long flags' with #define PMU_HAS_flags. But a named struct would work too I suppose.
> > > Would it only hold an "overflow_interrupt_available" flag, or are > > > there other generic capabilities it would be handy to know about? > > > > Possible (other) flags could be: > > > > PMU_HAS_INT -- would allow sampling events > > PMU_HAS_PRECISE -- would allow any ::precise value > > PMU_HAS_FILTER -- would allow all os/user/etc. flags > > should we export these to userspace somehow? > > It would be handy to be able to tell you're getting EOPNOTSUP because > PMU_HAS_INT is not set for your pmu, rather than trying to guess why > things are failing.
Yeah I suppose we could do something like that. Maybe something like:
# cat /sys/bus/event_source/devices/cpu/flags int precise filter
?
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