Re: PEBS bug on HSW: "Unexpected number of pebs records 10" (was: Re:[GIT PULL] perf changes for v3.12)

From: Ramkumar Ramachandra
Date: Tue Sep 10 2013 - 08:43:14 EST


Stephane Eranian wrote:
> [ 2229.021966] Call Trace:
> [ 2229.021967] <NMI> [<ffffffff8159dcd6>] dump_stack+0x46/0x58
> [ 2229.021976] [<ffffffff8108dfdc>] warn_slowpath_common+0x8c/0xc0
> [ 2229.021979] [<ffffffff8108e0c6>] warn_slowpath_fmt+0x46/0x50
> [ 2229.021982] [<ffffffff810646c8>] intel_pmu_drain_pebs_hsw+0xa8/0xc0
> [ 2229.021986] [<ffffffff810668f0>] intel_pmu_handle_irq+0x220/0x380
> [ 2229.021991] [<ffffffff810c1d35>] ? sched_clock_cpu+0xc5/0x120
> [ 2229.021995] [<ffffffff815a5a84>] perf_event_nmi_handler+0x34/0x60
> [ 2229.021998] [<ffffffff815a52b8>] nmi_handle.isra.3+0x88/0x180
> [ 2229.022001] [<ffffffff815a5490>] do_nmi+0xe0/0x330
> [ 2229.022004] [<ffffffff815a48f7>] end_repeat_nmi+0x1e/0x2e
> [ 2229.022008] [<ffffffff810652b3>] ? intel_pmu_pebs_enable_all+0x33/0x40
> [ 2229.022011] [<ffffffff810652b3>] ? intel_pmu_pebs_enable_all+0x33/0x40
> [ 2229.022015] [<ffffffff810652b3>] ? intel_pmu_pebs_enable_all+0x33/0x40
> [ 2229.022016] <<EOE>> [<ffffffff810659f3>] intel_pmu_enable_all+0x23/0xa0
> [ 2229.022021] [<ffffffff8105ff84>] x86_pmu_enable+0x274/0x310
> [ 2229.022025] [<ffffffff81141927>] perf_pmu_enable+0x27/0x30
> [ 2229.022029] [<ffffffff81143219>] perf_event_context_sched_in+0x79/0xc0

Unnecessary repetition of the same task on multiple cores seems to be
the issue, although I'm not sure. Haven't gone through mingo's trace
yet.
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