Messages in this thread | | | From | Alex Shi <> | Date | Tue, 2 Jan 2024 21:00:22 +0800 | Subject | Re: [PATCH] sched/tracing: correct the task blocking state |
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On Tue, Jan 2, 2024 at 6:19 PM Valentin Schneider <vschneid@redhat.com> wrote: > > 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.
Hi Valentin, Thanks a lot for the reply.
I agree with you the current usage, but if so, we account for the idle task into blocked state. And it's better to distinguish between idle and block.
> > > 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). >
Right, maybe it's time to add a new state for TASK_IDLE?
Many thanks! Alex Shi
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