Messages in this thread | | | From | Valentin Schneider <> | Subject | Re: [PATCH] sched/tracing: correct the task blocking state | Date | Tue, 02 Jan 2024 11:18:52 +0100 |
| |
On 02/01/24 15:33, alexs@kernel.org wrote: > From: Alex Shi <alexs@kernel.org> > > commit 80ed87c8a9ca ("sched/wait: Introduce TASK_NOLOAD and TASK_IDLE") > stopped the idle kthreads contribution to loadavg. Also task idle should > separated from blocked state too, otherwise we will get incorrect task > blocking state from event tracing sched:sched_stat_blocked. >
Why is that incorrect? AFAICT we have mapped the (schedstat) 'blocked' meaning to TASK_UNINTERRUPTIBLE. TASK_IDLE tasks don't contribute to loadavg yes, but they are still in an UNINTERRUPTIBLE wait.
> diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c > index b28114478b82..b6afa596f071 100644 > --- a/kernel/sched/deadline.c > +++ b/kernel/sched/deadline.c > @@ -1570,7 +1570,7 @@ update_stats_dequeue_dl(struct dl_rq *dl_rq, struct sched_dl_entity *dl_se, > __schedstat_set(p->stats.sleep_start, > rq_clock(rq_of_dl_rq(dl_rq))); > > - if (state & TASK_UNINTERRUPTIBLE) > + if (is_blocked_task_state(state)) > __schedstat_set(p->stats.block_start, > rq_clock(rq_of_dl_rq(dl_rq)));
This change makes it so tasks waiting in TASK_IDLE have their waiting ignored by schedstat (they are seen as neither INTERRUPTIBLE nor UNINTERRUPTIBLE).
| |