On Thu, Jul 16, 2015 at 12:15 AM, Peter Zijlstra <[email protected]> wrote:
> On Thu, Jul 16, 2015 at 08:02:03AM +0200, Stephane Eranian wrote:
>> Been running it for a couple of hours, so far so good. I will let it
>> run all night.
>
> Thanks!
>
Well, it died on NHM in the same function despite your patch. Need to
look at the exact warning.\
So more work is needed. But then I also saw the irq loop stuck message
before that.
>> > ---
>> > arch/x86/kernel/cpu/perf_event_intel_ds.c | 29
>> > +++++++++++++----------------
>> > 1 file changed, 13 insertions(+), 16 deletions(-)
>> >
>> > diff --git a/arch/x86/kernel/cpu/perf_event_intel_ds.c
>> > b/arch/x86/kernel/cpu/perf_event_intel_ds.c
>> > index 71fc40238843..68d0ced1d229 100644
>> > --- a/arch/x86/kernel/cpu/perf_event_intel_ds.c
>> > +++ b/arch/x86/kernel/cpu/perf_event_intel_ds.c
>> > @@ -1142,6 +1142,7 @@ static void intel_pmu_drain_pebs_nhm(struct pt_regs
>> > *iregs)
>> >
>> > for (at = base; at < top; at += x86_pmu.pebs_record_size) {
>> > struct pebs_record_nhm *p = at;
>> > + u64 pebs_status;
>> >
>> > /* PEBS v3 has accurate status bits */
>> > if (x86_pmu.intel_cap.pebs_format >= 3) {
>> > @@ -1152,12 +1153,14 @@ static void intel_pmu_drain_pebs_nhm(struct
>> > pt_regs *iregs)
>> > continue;
>> > }
>> >
>> > - bit = find_first_bit((unsigned long *)&p->status,
>> > + pebs_status = p->status & cpuc->pebs_enabled;
>> > + pebs_status &= (1ULL << x86_pmu.max_pebs_events) - 1;
>> > +
>> > + bit = find_first_bit((unsigned long *)&pebs_status,
>> > x86_pmu.max_pebs_events);
>> > if (bit >= x86_pmu.max_pebs_events)
>> > continue;
>
> Maybe we should WARN in this case? A PEBS entry without any PEBS bits
> set in the status field would be 'weird', right?
>
> Maybe something like:
>
> if (WARN(bit >= x86_pmu.max_pebs_events,
> "PEBS record without PEBS event! status=%Lx
> pebs_enabled=%Lx active_mask=%Lx",
> p->status, cpuc->pebs_enabled, cpuc->active_mask))
> continue;
>
> If that triggers we at least get more info.
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