Messages in this thread | | | Date | Tue, 25 Aug 2015 17:07:06 +0900 | From | Namhyung Kim <> | Subject | Re: [RFC/PATCH] perf sched: Implement 'perf sched runtime' command |
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Hi David,
On Mon, Aug 24, 2015 at 11:19:44PM -0700, David Ahern wrote: > On 8/24/15 11:11 PM, Namhyung Kim wrote: > > > >+static int perf_sched__read_runtime_events(struct perf_sched *sched) > >+{ > >+ const struct perf_evsel_str_handler handlers[] = { > >+ { "sched:sched_switch", process_sched_switch_event, }, > >+ { "sched:sched_stat_runtime", process_sched_runtime_event, }, > >+ { "sched:sched_stat_sleep", process_sched_sleep_event, }, > >+ { "sched:sched_stat_wait", process_sched_wait_event, }, > >+ { "sched:sched_stat_iowait", process_sched_iowait_event, }, > >+ { "sched:sched_migrate_task", process_sched_migrate_task_event, }, > >+ }; > > I like the concept (obviously since I have invested so much time in other > solutions). But... you cannot rely on the sched_stat tracepoints being > enabled. I believe it is a performance hit to have CONFIG_SCHEDSTATS enabled > and distributions (e.g., Fedora) do not have it enabled.
Yes, I know that some distributions don't enable SCHEDSTATS. But as perf sched record already requires it, I think it's ok to use those events in other sched commands.
Maybe we could fix 'perf sched record' not to requires SCHEDSTATS. All commands in perf sched just use stat_runtime event currently. And I guess we can calculate/approximate the stat times using sched_switch events (and wakeup events) only. But it also requires changing other sched commands not to use sched_stat_runtime.
Thanks, Namhyung
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