Messages in this thread | | | Date | Tue, 27 Nov 2018 09:39:28 -0300 | From | Arnaldo Carvalho de Melo <> | Subject | Re: [PATCH] perf intel-pt: Fix error with config term pt=0 |
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Em Tue, Nov 27, 2018 at 10:43:36AM +0200, Adrian Hunter escreveu: > Users should never use 'pt=0', but if they do it may give a meaningless > error: > > $ perf record -e intel_pt/pt=0/u uname > Error: > The sys_perf_event_open() syscall returned with 22 (Invalid argument) for > event (intel_pt/pt=0/u). > > Fix that by forcing 'pt=1'. > > Signed-off-by: Adrian Hunter <adrian.hunter@intel.com> > --- > tools/perf/arch/x86/util/intel-pt.c | 8 ++++++++ > 1 file changed, 8 insertions(+) > > diff --git a/tools/perf/arch/x86/util/intel-pt.c b/tools/perf/arch/x86/util/intel-pt.c > index db0ba8caf5a2..af25a7824ee0 100644 > --- a/tools/perf/arch/x86/util/intel-pt.c > +++ b/tools/perf/arch/x86/util/intel-pt.c > @@ -524,10 +524,18 @@ static int intel_pt_validate_config(struct perf_pmu *intel_pt_pmu, > struct perf_evsel *evsel) > { > int err; > + char c; > > if (!evsel) > return 0; > > + /* > + * If supported, force pass-through config term (pt=1) even if user > + * sets pt=0, which avoids senseless kernel errors. > + */ > + if (perf_pmu__scan_file(intel_pt_pmu, "format/pt", "%c", &c) == 1) > + evsel->attr.config |= 1;
shouldn't we have a warning like:
pr_warning("pt=0 doesn't make sense, forcing pt=1")
Instead of silently doing something the user, mistakenly, did explicitely?
- Arnaldo
> + > err = intel_pt_val_config_term(intel_pt_pmu, "caps/cycle_thresholds", > "cyc_thresh", "caps/psb_cyc", > evsel->attr.config); > -- > 2.17.1
--
- Arnaldo
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