From 9953807c9e016759c86ec0d0ab6bfe223e19f0ba Mon Sep 17 00:00:00 2001 From: Kan Liang Date: Sun, 8 Sep 2024 13:28:47 -0700 Subject: [PATCH] perf evlist: Print hint for group An event group is a critical relationship. There is a -g option that can display the relationship. But it's hard for a user to know when should this option be applied. If there is an event group in the perf record, print a hint to suggest the user apply the -g to display the group information. With the patch, $ perf record -e "{cycles,instructions},instructions" sleep 1 [ perf record: Woken up 1 times to write data ] [ perf record: Captured and wrote 0.024 MB perf.data (4 samples) ] $ $ perf evlist cycles instructions instructions # Tip: use 'perf evlist -g' to show group information $ perf evlist -g {cycles,instructions} instructions $ Committer testing: So for a perf.data file _with_ a group: root@number:~# perf evlist -g {cpu_core/branch-instructions/pp,cpu_core/branches/} dummy:u root@number:~# perf evlist cpu_core/branch-instructions/pp cpu_core/branches/ dummy:u # Tip: use 'perf evlist -g' to show group information root@number:~# Then for something _without_ a group, no hint: root@number:~# perf record ls [ perf record: Woken up 1 times to write data ] [ perf record: Captured and wrote 0.035 MB perf.data (7 samples) ] root@number:~# perf evlist cpu_atom/cycles/P cpu_core/cycles/P dummy:u root@number:~# No suggestion, good. Suggested-by: Arnaldo Carvalho de Melo Reviewed-by: Ian Rogers Signed-off-by: Kan Liang Tested-by: Arnaldo Carvalho de Melo Cc: Adrian Hunter Cc: Jiri Olsa Cc: Namhyung Kim Closes: https://lore.kernel.org/lkml/ZttgvduaKsVn1r4p@x1/ Link: https://lore.kernel.org/r/20240908202847.176280-1-kan.liang@linux.intel.com Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/builtin-evlist.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/tools/perf/builtin-evlist.c b/tools/perf/builtin-evlist.c index 818ab21c3f735..a9bd7bbef5a96 100644 --- a/tools/perf/builtin-evlist.c +++ b/tools/perf/builtin-evlist.c @@ -36,7 +36,7 @@ static int __cmd_evlist(const char *file_name, struct perf_attr_details *details .force = details->force, }; struct perf_tool tool; - bool has_tracepoint = false; + bool has_tracepoint = false, has_group = false; perf_tool__init(&tool, /*ordered_events=*/false); /* only needed for pipe mode */ @@ -54,11 +54,17 @@ static int __cmd_evlist(const char *file_name, struct perf_attr_details *details if (pos->core.attr.type == PERF_TYPE_TRACEPOINT) has_tracepoint = true; + + if (!evsel__is_group_leader(pos)) + has_group = true; } if (has_tracepoint && !details->trace_fields) printf("# Tip: use 'perf evlist --trace-fields' to show fields for tracepoint events\n"); + if (has_group && !details->event_group) + printf("# Tip: use 'perf evlist -g' to show group information\n"); + perf_session__delete(session); return 0; } -- 2.50.1