Messages in this thread | | | From | "Liang, Kan" <> | Subject | RE: [PATCH] perf tools: set no branch type for dummy event in PT | Date | Thu, 29 Jun 2017 15:31:45 +0000 |
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> On Wed, Jun 28, 2017 at 10:31:53AM -0400, kan.liang@intel.com wrote: > > 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 branch_type=no for dummy event in Intel PT. > > > > Signed-off-by: Kan Liang <kan.liang@intel.com> > > --- > > tools/perf/arch/x86/util/intel-pt.c | 19 +++++++++++++++++++ > > 1 file changed, 19 insertions(+) > > > > diff --git a/tools/perf/arch/x86/util/intel-pt.c > > b/tools/perf/arch/x86/util/intel-pt.c > > index f630de0..651ab9e 100644 > > --- a/tools/perf/arch/x86/util/intel-pt.c > > +++ b/tools/perf/arch/x86/util/intel-pt.c > > @@ -544,6 +544,22 @@ static int intel_pt_validate_config(struct perf_pmu > *intel_pt_pmu, > > evsel->attr.config); > > } > > > > +static int add_no_lbr_config_term(struct list_head *config_terms) { > > + struct perf_evsel_config_term *lbr_term; > > + > > + lbr_term = zalloc(sizeof(*lbr_term)); > > + if (!lbr_term) > > + return -ENOMEM; > > + > > + INIT_LIST_HEAD(&lbr_term->list); > > + lbr_term->type = PERF_EVSEL__CONFIG_TERM_BRANCH; > > + lbr_term->val.branch = strdup("no"); > > + list_add_tail(&lbr_term->list, config_terms); > > + > > + return 0; > > +} > > + > > static int intel_pt_recording_options(struct auxtrace_record *itr, > > struct perf_evlist *evlist, > > struct record_opts *opts) > > @@ -701,6 +717,8 @@ static int intel_pt_recording_options(struct > auxtrace_record *itr, > > perf_evsel__set_sample_bit(switch_evsel, > TIME); > > perf_evsel__set_sample_bit(switch_evsel, > CPU); > > > > + add_no_lbr_config_term(&switch_evsel- > >config_terms); > > + > > hum, why can't you change the sample bit directly? with: > > perf_evsel__reset_sample_bit(switch_evsel, > BRANCH_STACK);
It will be overwrite in perf_evsel__config.
Thanks, Kan
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