* [PATCH v2 2/2] perf evsel: Improve error message for uncore events
2021-12-23 18:39 [PATCH v2 1/2] perf test: Enable system wide for metricgroups test Ian Rogers
@ 2021-12-23 18:39 ` Ian Rogers
0 siblings, 0 replies; 2+ messages in thread
From: Ian Rogers @ 2021-12-23 18:39 UTC (permalink / raw)
To: Peter Zijlstra, Ingo Molnar, Arnaldo Carvalho de Melo,
Mark Rutland, Alexander Shishkin, Jiri Olsa, Namhyung Kim,
Andi Kleen, linux-perf-users, linux-kernel
Cc: eranian, Ian Rogers
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'.
v2. Changed the test to use !target__has_cpu as suggested by Namhyung
Kim.
Signed-off-by: Ian Rogers <irogers@google.com>
---
tools/perf/util/evsel.c | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/tools/perf/util/evsel.c b/tools/perf/util/evsel.c
index 656c30b988ce..a0acf53a2510 100644
--- a/tools/perf/util/evsel.c
+++ b/tools/perf/util/evsel.c
@@ -2931,6 +2931,10 @@ 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 (!target__has_cpu(target))
+ return scnprintf(msg, size,
+ "Invalid event (%s) in per-thread mode, enable system wide with '-a'.",
+ evsel__name(evsel));
break;
case ENODATA:
return scnprintf(msg, size, "Cannot collect data source with the load latency event alone. "
--
2.34.1.307.g9b7440fafd-goog
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