From: Peter Zijlstra <peterz@infradead.org>
To: Dave Kleikamp <dave.kleikamp@oracle.com>
Cc: LKML <linux-kernel@vger.kernel.org>, Ingo Molnar <mingo@redhat.com>
Subject: Re: [PATCH RESEND 1/1] sched/rt: minimize rq->lock contention in, do_sched_rt_period_timer()
Date: Tue, 16 May 2017 10:14:53 +0200 [thread overview]
Message-ID: <20170516081453.titdkpplakvhzydw@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <a767637b-df85-912f-ba69-c90ee00a3fb6@oracle.com>
On Mon, May 15, 2017 at 02:14:13PM -0500, Dave Kleikamp wrote:
> With CONFIG_RT_GROUP_SCHED defined, do_sched_rt_period_timer() sequentially
> takes each cpu's rq->lock. On a large, busy system, the cumulative time it
> takes to acquire each lock can be excessive, even triggering a watchdog
> timeout.
>
> If rt_rq_rt_time and rt_rq->rt_nr_running are both zero, this function does
> nothing while holding the lock, so don't bother taking it at all.
Indeed, thanks Dave!
next prev parent reply other threads:[~2017-05-16 8:15 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-05-15 19:13 [PATCH RESEND 0/1] sched/rt: minimize rq->lock contention in, do_sched_rt_period_timer() Dave Kleikamp
2017-05-15 19:14 ` [PATCH RESEND 1/1] " Dave Kleikamp
2017-05-16 8:14 ` Peter Zijlstra [this message]
2017-05-23 8:46 ` [tip:sched/core] sched/rt: Minimize rq->lock contention in do_sched_rt_period_timer() tip-bot for Dave Kleikamp
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