| Date | Thu, 15 Jan 2015 10:06:59 +0100 | From | Peter Zijlstra <> | Subject | Re: [PATCH v9 12/14] x86: perf: intel_pt: Intel PT PMU driver |
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On Wed, Jan 14, 2015 at 02:18:21PM +0200, Alexander Shishkin wrote: > +static __init int pt_init(void) > +{
> + pt_pmu.pmu.attr_groups = pt_attr_groups; > + pt_pmu.pmu.task_ctx_nr = perf_hw_context;
I just noticed this one, how can this ever work? We want the PT thing to always get programmed, right? -- because we disallow creating more than 1?
Which reminds me; does that exclusive thing you did not allow you to create one cpu wide and one per task (they're separate contexts) events? At which point we're not schedulable at all.
By sticking it on the HW context list it can end up not being programed because its stuck after a bunch of hardware events that don't all fit on the PMU.
Would not the SW list be more appropriate; the SW list is a list of events that's guaranteed to be schedulable.
> + pt_pmu.pmu.event_init = pt_event_init; > + pt_pmu.pmu.add = pt_event_add; > + pt_pmu.pmu.del = pt_event_del; > + pt_pmu.pmu.start = pt_event_start; > + pt_pmu.pmu.stop = pt_event_stop; > + pt_pmu.pmu.read = pt_event_read; > + pt_pmu.pmu.setup_aux = pt_buffer_setup_aux; > + pt_pmu.pmu.free_aux = pt_buffer_free_aux; > + ret = perf_pmu_register(&pt_pmu.pmu, "intel_pt", -1); > + > + return ret; > +}
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