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perf/x86: Remove warning for zero PEBS status 

The recent commit:

  75f80859b1 ("perf/x86/intel/pebs: Robustify PEBS buffer drain")

causes lots of warnings on different CPUs before Skylake
when running PEBS intensive workloads.

They can have a zero status field in the PEBS record when
PEBS is racing with clearing of GLOBAl_STATUS.

This also can cause hangs (it seems there are still
problems with printk in NMI).

Disable the warning, but still ignore the record.

Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Link: http://lkml.kernel.org/r/1449177740-5422-1-git-send-email-andi@firstfloor.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
hifive-unleashed-5.1
Andi Kleen 2015-12-03 13:22:19 -08:00 committed by Ingo Molnar
parent 7b648018f6
commit 957ea1fdbc
1 changed files with 1 additions and 4 deletions
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5
arch/x86/kernel/cpu/perf_event_intel_ds.c
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@ -1232,10 +1232,7 @@ static void intel_pmu_drain_pebs_nhm(struct pt_regs *iregs)
bit = find_first_bit((unsigned long *)&pebs_status,
x86_pmu.max_pebs_events);
if (WARN(bit >= x86_pmu.max_pebs_events,
"PEBS record without PEBS event! status=%Lx pebs_enabled=%Lx active_mask=%Lx",
(unsigned long long)p->status, (unsigned long long)cpuc->pebs_enabled,
*(unsigned long long *)cpuc->active_mask))
if (bit >= x86_pmu.max_pebs_events)
continue;
/*