Messages in this thread Patch in this message | | | From | kan.liang@intel ... | Subject | [PATCH V2 2/2] perf tools: always set no branch for dummy event in PT | Date | Fri, 30 Jun 2017 10:16:56 -0400 |
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From: Kan Liang <kan.liang@intel.com>
An earlier kernel patch allowed enabling PT and LBR at the same time on Goldmont.
commit ccbebba4c6bf ("perf/x86/intel/pt: Bypass PT vs. LBR exclusivity if the core supports it")
However, users still cannot use Intel PT and LBRs simultaneously. $ sudo perf record -e cycles,intel_pt//u -b -- sleep 1 Error: PMU Hardware doesn't support sampling/overflow-interrupts.
PT implicitly adds dummy event in perf tool. dummy event is software event which doesn't support LBR.
Always setting no branch for dummy event in Intel PT.
Signed-off-by: Kan Liang <kan.liang@intel.com> ---
Changes since V1 - change the BRANCH_STACK sample bit directly (jirka)
tools/perf/arch/x86/util/intel-pt.c | 2 ++ 1 file changed, 2 insertions(+)
diff --git a/tools/perf/arch/x86/util/intel-pt.c b/tools/perf/arch/x86/util/intel-pt.c index 4fe1aed..2201f3b 100644 --- a/tools/perf/arch/x86/util/intel-pt.c +++ b/tools/perf/arch/x86/util/intel-pt.c @@ -700,6 +700,7 @@ static int intel_pt_recording_options(struct auxtrace_record *itr, perf_evsel__set_sample_bit(switch_evsel, TID); perf_evsel__set_sample_bit(switch_evsel, TIME); perf_evsel__set_sample_bit(switch_evsel, CPU); + perf_evsel__reset_sample_bit(switch_evsel, BRANCH_STACK); opts->record_switch_events = false; ptr->have_sched_switch = 3; @@ -761,6 +762,7 @@ static int intel_pt_recording_options(struct auxtrace_record *itr, /* And the CPU for switch events */ perf_evsel__set_sample_bit(tracking_evsel, CPU); } + perf_evsel__reset_sample_bit(tracking_evsel, BRANCH_STACK); } /* -- 2.9.4
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