Messages in this thread | | | Date | Fri, 12 Mar 2010 00:31:28 +0300 | From | Cyrill Gorcunov <> | Subject | Re: [RFC] x86,perf: Implement minimal P4 PMU driver v14 |
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On Thu, Mar 11, 2010 at 10:24:22PM +0100, Peter Zijlstra wrote: > On Fri, 2010-03-12 at 00:15 +0300, Cyrill Gorcunov wrote: > > > Perhaps something like the patch below (tested with kvm)? With this patch > > we will actually waste ~4/8 bytes per PMU (intel,amd,p6) since this call > > hits on p4 only, so I think perhaps better to use one x86 scheduler hook > > instead of empty schedule_events() in PMU, hmm? > > --- > > > > x86,perf: Fix NULL deref on not assigned x86_pmu > > > > In case of not assigned x86_pmu and software events > > NULL dereference may being hit via x86_pmu::schedule_events > > method. > > > > Fix it by calling x86_pmu::schedule_events only if we > > have one. Otherwise use general scheduler. > > > > Also the former x86_schedule_events calls restored. > > Hrm,.. not sure that makes sense, sure it might not crash anymore, but > its not making much sense to compute anything if we don't have an > initialized x86_pmu. > > Doesn't adding something like: > > if (!x86_pmu_initialized()) > return; > > to hw_perf_group_sched_in() make more sense? We seem to do that for all > these weak things except this one. >
As far as I see it'll not update tstamp_running then (in x86_event_sched_in). Or I miss somethig?
-- Cyrill
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