From 8b3c9ea7bf8f50ead6787c084cfc6d3a0b1e38aa Mon Sep 17 00:00:00 2001 From: Arnaldo Carvalho de Melo Date: Thu, 15 Aug 2019 12:02:13 -0300 Subject: [PATCH] perf evswitch: Add hint when not finding specified on/off events If the user specifies a on or off switch event and it isn't in the perf.data file, provide a hint about how to see the events in the perf.data evlist: # perf script --switch-on=syscall:sys_enter_nanosleep --switch-off=syscalls:sys_exit_nanosleep ERROR: event_on event not found (syscall:sys_enter_nanosleep) HINT: use 'perf evlist' to see the available event names # # perf evlist sched:sched_kthread_stop sched:sched_kthread_stop_ret sched:sched_waking sched:sched_wakeup sched:sched_wakeup_new sched:sched_switch sched:sched_migrate_task sched:sched_process_free sched:sched_process_exit sched:sched_wait_task sched:sched_process_wait sched:sched_process_fork sched:sched_process_exec sched:sched_stat_wait sched:sched_stat_sleep sched:sched_stat_iowait sched:sched_stat_blocked sched:sched_stat_runtime sched:sched_pi_setprio sched:sched_move_numa sched:sched_stick_numa sched:sched_swap_numa sched:sched_wake_idle_without_ipi syscalls:sys_enter_clock_nanosleep syscalls:sys_exit_clock_nanosleep syscalls:sys_enter_nanosleep syscalls:sys_exit_nanosleep # Tip: use 'perf evlist --trace-fields' to show fields for tracepoint events # # perf script --switch-on=syscalls:sys_enter_nanosleep --switch-off=syscalls:sys_exit_nanosleep sleep 20919 [001] 109866.144411: sched:sched_stat_runtime: comm=sleep pid=20919 runtime=521249 [ns] vruntime=202919398131 [ns] sleep 20919 [001] 109866.144412: sched:sched_switch: sleep:20919 [120] S ==> swapper/1:0 [120] swapper 0 [001] 109867.144568: sched:sched_waking: comm=sleep pid=20919 prio=120 target_cpu=001 swapper 0 [001] 109867.144586: sched:sched_wakeup: sleep:20919 [120] success=1 CPU:001 # Cc: Adrian Hunter Cc: Florian Weimer Cc: Jiri Olsa Cc: Namhyung Kim Cc: William Cohen Link: https://lkml.kernel.org/n/tip-iijjvdlyad973oskdq8gmi5w@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/util/evswitch.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/tools/perf/util/evswitch.c b/tools/perf/util/evswitch.c index 71daed615a2c..3ba72f743d3c 100644 --- a/tools/perf/util/evswitch.c +++ b/tools/perf/util/evswitch.c @@ -33,7 +33,9 @@ bool evswitch__discard(struct evswitch *evswitch, struct evsel *evsel) static int evswitch__fprintf_enoent(FILE *fp, const char *evtype, const char *evname) { - return fprintf(fp, "ERROR: switch-%s event not found (%s)\n", evtype, evname); + int printed = fprintf(fp, "ERROR: switch-%s event not found (%s)\n", evtype, evname); + + return printed += fprintf(fp, "HINT: use 'perf evlist' to see the available event names\n"); } int evswitch__init(struct evswitch *evswitch, struct evlist *evlist, FILE *fp)