From c9a8c343ef2f9769a33650b7429f5a83ecba8380 Mon Sep 17 00:00:00 2001 From: Ian Rogers Date: Wed, 3 Dec 2025 13:47:04 -0800 Subject: [PATCH] perf stat: When no events, don't report an error if there is none Events may fail to open as no supported CPUs were specified on the command line. In this case a confusing "error" message of "success" can be reported. Let's skip the error in that case. Before: ``` $ perf stat -C2048 -e cycles -- true WARNING: A requested CPU in '2048' is not supported by PMU 'cpu' (CPUs 0-7) for event 'cycles' Error: No supported events found. The sys_perf_event_open() syscall returned with 0 (Success) for event (cpu/unknown-hardware/). "dmesg | grep -i perf" may provide additional information. ``` After: ``` $ perf stat -C2048 -e cycles -- true WARNING: A requested CPU in '2048' is not supported by PMU 'cpu' (CPUs 0-7) for event 'cycles' Error: No supported events found. ``` Signed-off-by: Ian Rogers Tested-by: Thomas Richter Signed-off-by: Namhyung Kim --- tools/perf/builtin-stat.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/tools/perf/builtin-stat.c b/tools/perf/builtin-stat.c index 6410115ed9c5e..bd3c3de8d2009 100644 --- a/tools/perf/builtin-stat.c +++ b/tools/perf/builtin-stat.c @@ -924,8 +924,10 @@ static int __run_perf_stat(int argc, const char **argv, int run_idx) } } if (!has_supported_counters && !stat_config.null_run) { - evsel__open_strerror(evlist__first(evsel_list), &target, open_err, - msg, sizeof(msg)); + if (open_err) { + evsel__open_strerror(evlist__first(evsel_list), &target, open_err, + msg, sizeof(msg)); + } ui__error("No supported events found.\n%s\n", msg); if (child_pid != -1) -- 2.47.3