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| Started by | Andi Kleen <andi@firstfloor.org> |
|---|---|
| First post | 2015-12-03 22:30 +0100 |
| Last post | 2015-12-03 22:30 +0100 |
| Articles | 2 — 2 participants |
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[PATCH 1/2] x86, perf: Remove warning for zero PEBS status Andi Kleen <andi@firstfloor.org> - 2015-12-03 22:30 +0100
Re: [PATCH 1/2] x86, perf: Remove warning for zero PEBS status Peter Zijlstra <peterz@infradead.org> - 2015-12-03 22:30 +0100
| From | Andi Kleen <andi@firstfloor.org> |
|---|---|
| Date | 2015-12-03 22:30 +0100 |
| Subject | [PATCH 1/2] x86, perf: Remove warning for zero PEBS status |
| Message-ID | <qBJBU-22d-3@gated-at.bofh.it> |
From: Andi Kleen <ak@linux.intel.com> The recent change 75f80859b1 (... 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> --- arch/x86/kernel/cpu/perf_event_intel_ds.c | 5 +---- 1 file changed, 1 insertion(+), 4 deletions(-) diff --git a/arch/x86/kernel/cpu/perf_event_intel_ds.c b/arch/x86/kernel/cpu/perf_event_intel_ds.c index 7f11784..da294de 100644 --- a/arch/x86/kernel/cpu/perf_event_intel_ds.c +++ b/arch/x86/kernel/cpu/perf_event_intel_ds.c @@ -1237,10 +1237,7 @@ 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; /* -- 2.4.3 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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| From | Peter Zijlstra <peterz@infradead.org> |
|---|---|
| Date | 2015-12-03 22:30 +0100 |
| Message-ID | <qBJBU-22d-5@gated-at.bofh.it> |
| In reply to | #1283394 |
On Thu, Dec 03, 2015 at 01:22:19PM -0800, Andi Kleen wrote: > From: Andi Kleen <ak@linux.intel.com> > > The recent change 75f80859b1 (... 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. Ah, so _that_ is the explanation! Please put that in a comment near that code. This has long puzzled me. Thanks for digging into that. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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