From: Pavan Kondeti <pkondeti@codeaurora.org>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Pavan Kondeti <pkondeti@codeaurora.org>,
Steven Rostedt <rostedt@goodmis.org>,
LKML <linux-kernel@vger.kernel.org>,
Ingo Molnar <mingo@kernel.org>,
Andrew Morton <akpm@linux-foundation.org>
Subject: Re: [PATCH] sched: Optimize pick_next_task for idle_sched_class too
Date: Thu, 23 Feb 2017 22:59:15 +0530 [thread overview]
Message-ID: <CAEU1=PnoHKiBQyk7ArRbci4BFokhyr-9aazSHTMm9YbW8PHrQQ@mail.gmail.com> (raw)
In-Reply-To: <20170223163737.GW6536@twins.programming.kicks-ass.net>
On Thu, Feb 23, 2017 at 10:07 PM, Peter Zijlstra <peterz@infradead.org> wrote:
> On Thu, Feb 23, 2017 at 04:25:33PM +0100, Peter Zijlstra wrote:
>>
>> Ah, I read your question wrong. Yes I think you're right, we now loose
>> the pull when the last RT task goes away.
>>
>> Hmm.. how to fix that nicely..
>
> Something like so perhaps? This would make a pull happen when the last
> RT task on this CPU goes away.
>
> Steve?
>
> ---
> diff --git a/kernel/sched/rt.c b/kernel/sched/rt.c
> index 9f3e40226dec..283d591078b0 100644
> --- a/kernel/sched/rt.c
> +++ b/kernel/sched/rt.c
> @@ -1336,6 +1336,9 @@ static void dequeue_task_rt(struct rq *rq, struct task_struct *p, int flags)
> dequeue_rt_entity(rt_se, flags);
>
> dequeue_pushable_task(rq, p);
> +
> + if (!rq->rt.rt_nr_running)
> + queue_pull_task(rq);
> }
>
> /*
The next balance_callback() is not called until the context switch is
completed. So we potentially pick a lower class task before the pull
happens. Would it be wrong to call pull_rt_task() directly instead of
queuing the callback.
--
Qualcomm India Private Limited, on behalf of Qualcomm Innovation Center, Inc.
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a
Linux Foundation Collaborative Project
next prev parent reply other threads:[~2017-02-23 17:29 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-01-19 15:17 [PATCH] sched: Optimize pick_next_task for idle_sched_class too Steven Rostedt
2017-01-19 17:44 ` Peter Zijlstra
2017-01-20 16:14 ` Steven Rostedt
2017-01-20 16:16 ` Steven Rostedt
2017-01-20 16:52 ` Peter Zijlstra
2017-01-30 11:54 ` [tip:sched/core] sched/core: Optimize pick_next_task() for idle_sched_class tip-bot for Peter Zijlstra
2017-02-23 10:34 ` [PATCH] sched: Optimize pick_next_task for idle_sched_class too Pavan Kondeti
2017-02-23 13:54 ` Peter Zijlstra
2017-02-23 15:15 ` Pavan Kondeti
2017-02-23 15:25 ` Peter Zijlstra
2017-02-23 16:37 ` Peter Zijlstra
2017-02-23 17:29 ` Pavan Kondeti [this message]
2017-02-23 17:45 ` Peter Zijlstra
2017-02-23 17:54 ` Peter Zijlstra
2017-02-27 17:54 ` Steven Rostedt
2017-03-01 15:53 ` Steven Rostedt
2017-03-01 16:03 ` Peter Zijlstra
2017-03-01 16:19 ` Steven Rostedt
2017-03-01 16:22 ` Peter Zijlstra
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