The following commit has been merged into the perf/urgent branch of tip: Commit-ID: a8abc881981762631a22568d5e4b2c0ce4aeb15c Gitweb: https://git.kernel.org/tip/a8abc881981762631a22568d5e4b2c0ce4aeb15c Author: Kan Liang <kan.liang@xxxxxxxxxxxxxxx> AuthorDate: Mon, 30 Nov 2020 11:38:41 -08:00 Committer: Peter Zijlstra <peterz@xxxxxxxxxxxxx> CommitterDate: Mon, 01 Mar 2021 11:02:19 +01:00 perf/x86/intel: Set PERF_ATTACH_SCHED_CB for large PEBS and LBR To supply a PID/TID for large PEBS, it requires flushing the PEBS buffer in a context switch. For normal LBRs, a context switch can flip the address space and LBR entries are not tagged with an identifier, we need to wipe the LBR, even for per-cpu events. For LBR callstack, save/restore the stack is required during a context switch. Set PERF_ATTACH_SCHED_CB for the event with large PEBS & LBR. Fixes: 9c964efa4330 ("perf/x86/intel: Drain the PEBS buffer during context switches") Signed-off-by: Kan Liang <kan.liang@xxxxxxxxxxxxxxx> Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx> Link: https://lkml.kernel.org/r/20201130193842.10569-2-kan.liang@xxxxxxxxxxxxxxx --- arch/x86/events/intel/core.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/arch/x86/events/intel/core.c b/arch/x86/events/intel/core.c index 5bac48d..7bbb5bb 100644 --- a/arch/x86/events/intel/core.c +++ b/arch/x86/events/intel/core.c @@ -3662,8 +3662,10 @@ static int intel_pmu_hw_config(struct perf_event *event) if (!(event->attr.freq || (event->attr.wakeup_events && !event->attr.watermark))) { event->hw.flags |= PERF_X86_EVENT_AUTO_RELOAD; if (!(event->attr.sample_type & - ~intel_pmu_large_pebs_flags(event))) + ~intel_pmu_large_pebs_flags(event))) { event->hw.flags |= PERF_X86_EVENT_LARGE_PEBS; + event->attach_state |= PERF_ATTACH_SCHED_CB; + } } if (x86_pmu.pebs_aliases) x86_pmu.pebs_aliases(event); @@ -3676,6 +3678,7 @@ static int intel_pmu_hw_config(struct perf_event *event) ret = intel_pmu_setup_lbr_filter(event); if (ret) return ret; + event->attach_state |= PERF_ATTACH_SCHED_CB; /* * BTS is set up earlier in this path, so don't account twice
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