On Wed, Jun 08, 2016 at 09:56:12AM +0200, Ingo Molnar wrote:
>
> * Josh Poimboeuf <jpoim...@redhat.com> wrote:
>
> > --- a/kernel/sched/fair.c
> > +++ b/kernel/sched/fair.c
> > @@ -789,6 +789,13 @@ static void update_curr_fair(struct rq *rq)
> > update_curr(cfs_rq_of(&rq->curr->se));
> > }
> >
> > +void trace_sched_stat_register(void)
> > +{
> > +#ifdef CONFIG_SCHEDSTATS
> > + force_schedstat_enabled();
> > +#endif
> > +}
>
> I think it would be cleaner to provide an empty force_schedstat_enabled()
> definition in sched.h, on !CONFIG_SCHEDSTATS.
Yes, agreed.
> But it might make sense to further decouple schedstats from tracing?
Looking at how we could do that:
- The sched_stat_wait tracepoint is dependent on the wait_start schedstat.
- The sched_stat_sleep tracepoint is dependent on the sleep_start
schedstat.
- The sched_stat_iowait and sched_stat_blocked tracepoints are dependent
on the block_start schedstat.
We could move those three schedstats values out of sched_statistics and
into sched_entity, and then always update them regardless of
CONFIG_SCHEDSTATS.
That would ensure these tracepoints always work. But then again it
would add a little bit of runtime overhead.
I don't have a strong opinion either way. Thoughts?
--
Josh
