Re: [PATCH] Revert "perf/x86: Allow zero PEBS status with only single active event"

2021-03-16 Thread Namhyung Kim
On Tue, Mar 16, 2021 at 9:28 PM Liang, Kan wrote: > > > > On 3/16/2021 3:22 AM, Namhyung Kim wrote: > > Hi Peter and Kan, > > > > On Thu, Mar 4, 2021 at 5:22 AM Peter Zijlstra wrote: > >> > >> On Wed, Mar 03, 2021 at 02:53:00PM -0500, Liang, Kan wrote: > >>> On 3/3/2021 1:59 PM, Peter Zijlstra

Re: [PATCH] Revert "perf/x86: Allow zero PEBS status with only single active event"

2021-03-16 Thread Liang, Kan
On 3/16/2021 2:34 PM, Stephane Eranian wrote: On Tue, Mar 16, 2021 at 5:28 AM Liang, Kan wrote: On 3/16/2021 3:22 AM, Namhyung Kim wrote: Hi Peter and Kan, On Thu, Mar 4, 2021 at 5:22 AM Peter Zijlstra wrote: On Wed, Mar 03, 2021 at 02:53:00PM -0500, Liang, Kan wrote: On 3/3/2021

Re: [PATCH] Revert "perf/x86: Allow zero PEBS status with only single active event"

2021-03-16 Thread Stephane Eranian
On Tue, Mar 16, 2021 at 5:28 AM Liang, Kan wrote: > > > > On 3/16/2021 3:22 AM, Namhyung Kim wrote: > > Hi Peter and Kan, > > > > On Thu, Mar 4, 2021 at 5:22 AM Peter Zijlstra wrote: > >> > >> On Wed, Mar 03, 2021 at 02:53:00PM -0500, Liang, Kan wrote: > >>> On 3/3/2021 1:59 PM, Peter Zijlstra

Re: [PATCH] Revert "perf/x86: Allow zero PEBS status with only single active event"

2021-03-16 Thread Liang, Kan
On 3/16/2021 3:22 AM, Namhyung Kim wrote: Hi Peter and Kan, On Thu, Mar 4, 2021 at 5:22 AM Peter Zijlstra wrote: On Wed, Mar 03, 2021 at 02:53:00PM -0500, Liang, Kan wrote: On 3/3/2021 1:59 PM, Peter Zijlstra wrote: On Wed, Mar 03, 2021 at 05:42:18AM -0800, kan.li...@linux.intel.com

Re: [PATCH] Revert "perf/x86: Allow zero PEBS status with only single active event"

2021-03-16 Thread Namhyung Kim
Hi Peter and Kan, On Thu, Mar 4, 2021 at 5:22 AM Peter Zijlstra wrote: > > On Wed, Mar 03, 2021 at 02:53:00PM -0500, Liang, Kan wrote: > > On 3/3/2021 1:59 PM, Peter Zijlstra wrote: > > > On Wed, Mar 03, 2021 at 05:42:18AM -0800, kan.li...@linux.intel.com wrote: > > > > > +++

Re: [PATCH] Revert "perf/x86: Allow zero PEBS status with only single active event"

2021-03-03 Thread Liang, Kan
On 3/3/2021 1:59 PM, Peter Zijlstra wrote: On Wed, Mar 03, 2021 at 05:42:18AM -0800, kan.li...@linux.intel.com wrote: For some old CPUs (HSW and earlier), the PEBS status in a PEBS record may be mistakenly set to 0. To minimize the impact of the defect, the commit was introduced to try to

Re: [PATCH] Revert "perf/x86: Allow zero PEBS status with only single active event"

2021-03-03 Thread Peter Zijlstra
On Wed, Mar 03, 2021 at 02:53:00PM -0500, Liang, Kan wrote: > On 3/3/2021 1:59 PM, Peter Zijlstra wrote: > > On Wed, Mar 03, 2021 at 05:42:18AM -0800, kan.li...@linux.intel.com wrote: > > > +++ b/arch/x86/events/intel/ds.c > > > @@ -2000,18 +2000,6 @@ static void intel_pmu_drain_pebs_nhm(struct

Re: [PATCH] Revert "perf/x86: Allow zero PEBS status with only single active event"

2021-03-03 Thread Peter Zijlstra
On Wed, Mar 03, 2021 at 05:42:18AM -0800, kan.li...@linux.intel.com wrote: > For some old CPUs (HSW and earlier), the PEBS status in a PEBS record > may be mistakenly set to 0. To minimize the impact of the defect, the > commit was introduced to try to avoid dropping the PEBS record for some >

[PATCH] Revert "perf/x86: Allow zero PEBS status with only single active event"

2021-03-03 Thread kan . liang
From: Kan Liang This reverts commit 01330d7288e0 ("perf/x86: Allow zero PEBS status with only single active event") A repeatable crash can be triggered by the perf_fuzzer on some Haswell system. https://lore.kernel.org/lkml/7170d3b-c17f-1ded-52aa-cc6d9ae99...@maine.edu/ For some old CPUs (HSW