Commit-ID:  957ea1fdbcdb909e1540f06f06f1a9ce6e696efa
Gitweb:     http://git.kernel.org/tip/957ea1fdbcdb909e1540f06f06f1a9ce6e696efa
Author:     Andi Kleen <[email protected]>
AuthorDate: Thu, 3 Dec 2015 13:22:19 -0800
Committer:  Ingo Molnar <[email protected]>
CommitDate: Wed, 6 Jan 2016 11:15:30 +0100

perf/x86: Remove warning for zero PEBS status

The recent commit:

  75f80859b130 ("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 <[email protected]>
Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
Cc: Arnaldo Carvalho de Melo <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Stephane Eranian <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: Vince Weaver <[email protected]>
Link: 
http://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>
---
 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 5db1c77..0e3a9c7 100644
--- a/arch/x86/kernel/cpu/perf_event_intel_ds.c
+++ b/arch/x86/kernel/cpu/perf_event_intel_ds.c
@@ -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;
 
                /*
--
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