Messages in this thread | ![/](/images/icornerl.gif) | | Date | Thu, 3 Mar 2016 15:40:49 -0800 | Subject | Re: [PATCH 2/3] perf/x86/pebs: add workaround for broken OVFL status on HSW | From | Stephane Eranian <> |
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On Thu, Mar 3, 2016 at 1:43 PM, Andi Kleen <ak@linux.intel.com> wrote: > > > + /* > > + * There are cases where, even though, the PEBS ovfl bit is set in > > + * GLOBAL_OVF_STATUS, the PEBS events may also have their overflow bits > > + * set for their counters. We must clear them here because they have > > + * been processed as exact samples in the drain_pebs() routine. They > > + * must not be processed again in the for_each_bit_set() loop for > > + * regular samples below. > > + */ > > + status &= ~cpuc->pebs_enabled; > > + status &= x86_pmu.intel_ctrl | GLOBAL_STATUS_TRACE_TOPAPMI; > > If you just clear the bits here they will not be acked and stay around > forever in GLOBAL_STATUS, which causes other problems. > > You need a separate ack_status variable that contains all bits and is always > acked.
I understand that. You mean I need to that has all the bits that were set to call intel_pmu_ack_status().
But if you look at the code, and where I made the change, there is no more intel_pmu_ack_status() BEFORE you read the status again via intel_pmu_get_status().
So why would I need to keep another variable around?
> > > > -Andi > -- > ak@linux.intel.com -- Speaking for myself only
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