perf sched: Prefer sched_waking event when it exists

Commit fbd705a0c618 ("sched: Introduce the 'trace_sched_waking'
tracepoint") added sched_waking tracepoint which should be preferred
over sched_wakeup when analyzing scheduling delays.

Update 'perf sched record' to collect sched_waking events if it exists
and fallback to sched_wakeup if it does not. Similarly, update timehist
command to skip sched_wakeup events if the session includes sched_waking
(ie., sched_waking is preferred over sched_wakeup).

Signed-off-by: David Ahern <dsahern@kernel.org>
Acked-by: Namhyung Kim <namhyung@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Link: http://lore.kernel.org/lkml/20200807164844.44870-1-dsahern@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

diff --git a/tools/perf/builtin-sched.c b/tools/perf/builtin-sched.c
index 459e422..0c7d599 100644 (file)
--- a/tools/perf/builtin-sched.c
+++ b/tools/perf/builtin-sched.c
@@ -2398,6 +2398,15 @@ static void timehist_print_wakeup_event(struct perf_sched *sched,
        printf("\n");
 }
 
+static int timehist_sched_wakeup_ignore(struct perf_tool *tool __maybe_unused,
+                                       union perf_event *event __maybe_unused,
+                                       struct evsel *evsel __maybe_unused,
+                                       struct perf_sample *sample __maybe_unused,
+                                       struct machine *machine __maybe_unused)
+{
+       return 0;
+}
+
 static int timehist_sched_wakeup_event(struct perf_tool *tool,
                                       union perf_event *event __maybe_unused,
                                       struct evsel *evsel,
@@ -2958,9 +2967,10 @@ static int timehist_check_attr(struct perf_sched *sched,
 
 static int perf_sched__timehist(struct perf_sched *sched)
 {
-       const struct evsel_str_handler handlers[] = {
+       struct evsel_str_handler handlers[] = {
                { "sched:sched_switch",       timehist_sched_switch_event, },
                { "sched:sched_wakeup",       timehist_sched_wakeup_event, },
+               { "sched:sched_waking",       timehist_sched_wakeup_event, },
                { "sched:sched_wakeup_new",   timehist_sched_wakeup_event, },
        };
        const struct evsel_str_handler migrate_handlers[] = {
@@ -3018,6 +3028,11 @@ static int perf_sched__timehist(struct perf_sched *sched)
 
        setup_pager();
 
+       /* prefer sched_waking if it is captured */
+       if (perf_evlist__find_tracepoint_by_name(session->evlist,
+                                                 "sched:sched_waking"))
+               handlers[1].handler = timehist_sched_wakeup_ignore;
+
        /* setup per-evsel handlers */
        if (perf_session__set_tracepoints_handlers(session, handlers))
                goto out;
@@ -3330,12 +3345,16 @@ static int __cmd_record(int argc, const char **argv)
                "-e", "sched:sched_stat_iowait",
                "-e", "sched:sched_stat_runtime",
                "-e", "sched:sched_process_fork",
-               "-e", "sched:sched_wakeup",
                "-e", "sched:sched_wakeup_new",
                "-e", "sched:sched_migrate_task",
        };
+       struct tep_event *waking_event;
 
-       rec_argc = ARRAY_SIZE(record_args) + argc - 1;
+       /*
+        * +2 for either "-e", "sched:sched_wakeup" or
+        * "-e", "sched:sched_waking"
+        */
+       rec_argc = ARRAY_SIZE(record_args) + 2 + argc - 1;
        rec_argv = calloc(rec_argc + 1, sizeof(char *));
 
        if (rec_argv == NULL)
@@ -3344,6 +3363,13 @@ static int __cmd_record(int argc, const char **argv)
        for (i = 0; i < ARRAY_SIZE(record_args); i++)
                rec_argv[i] = strdup(record_args[i]);
 
+       rec_argv[i++] = "-e";
+       waking_event = trace_event__tp_format("sched", "sched_waking");
+       if (!IS_ERR(waking_event))
+               rec_argv[i++] = strdup("sched:sched_waking");
+       else
+               rec_argv[i++] = strdup("sched:sched_wakeup");
+
        for (j = 1; j < (unsigned int)argc; j++, i++)
                rec_argv[i] = argv[j];