Messages in this thread | | | Date | Sun, 28 Nov 2021 17:57:56 +0100 | From | Jiri Olsa <> | Subject | Re: [PATCH 2/2] perf evsel: Improve error message for uncore events |
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On Mon, Nov 22, 2021 at 06:03:41PM -0800, Ian Rogers wrote: > When a group has multiple events and the leader fails it can yield > errors like: > > $ perf stat -e '{uncore_imc/cas_count_read/},instructions' /bin/true > Error: > The sys_perf_event_open() syscall returned with 22 (Invalid argument) for event (uncore_imc/cas_count_read/). > /bin/dmesg | grep -i perf may provide additional information. > > However, when not the group leader <not supported> is given: > > $ perf stat -e '{instructions,uncore_imc/cas_count_read/}' /bin/true > ... > 1,619,057 instructions > <not supported> MiB uncore_imc/cas_count_read/ > > This is necessary because get_group_fd will fail if the leader fails and > is the direct result of the check on line 750 of builtin-stat.c in > stat_handle_error that returns COUNTER_SKIP for the latter case. > > This patch improves the error message to: > > $ perf stat -e '{uncore_imc/cas_count_read/},instructions' /bin/true > Error: > Invalid event (uncore_imc/cas_count_read/) in per-thread mode, enable system wide with '-a'. > > Signed-off-by: Ian Rogers <irogers@google.com> > --- > tools/perf/util/evsel.c | 5 +++++ > 1 file changed, 5 insertions(+) > > diff --git a/tools/perf/util/evsel.c b/tools/perf/util/evsel.c > index a59fb2ecb84e..48696ff4bddb 100644 > --- a/tools/perf/util/evsel.c > +++ b/tools/perf/util/evsel.c > @@ -2950,6 +2950,11 @@ int evsel__open_strerror(struct evsel *evsel, struct target *target, > return scnprintf(msg, size, "wrong clockid (%d).", clockid); > if (perf_missing_features.aux_output) > return scnprintf(msg, size, "The 'aux_output' feature is not supported, update the kernel."); > + if ((evsel__leader(evsel) == evsel) && > + (evsel->core.leader->nr_members > 1)) > + return scnprintf(msg, size, > + "Invalid event (%s) in per-thread mode, enable system wide with '-a'.", > + evsel__name(evsel));
should we rather check 'target' pointer for the per-thread mode? I'm not sure that per-thread mode will always be the case for the failure
jirka
> break; > case ENODATA: > return scnprintf(msg, size, "Cannot collect data source with the load latency event alone. " > -- > 2.34.0.rc2.393.gf8c9666880-goog >
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