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From: Juri Lelli <juri.lelli@arm.com>
To: Peter Zijlstra <peterz@infradead.org>,
	Frederic Weisbecker <fweisbec@gmail.com>
Cc: LKML <linux-kernel@vger.kernel.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	Preeti U Murthy <preeti@linux.vnet.ibm.com>,
	Christoph Lameter <cl@linux.com>, Ingo Molnar <mingo@kernel.org>,
	Viresh Kumar <viresh.kumar@linaro.org>,
	Rik van Riel <riel@redhat.com>
Subject: Re: [PATCH 07/10] sched: Migrate sched to use new tick dependency mask model
Date: Mon, 10 Aug 2015 15:02:04 +0100	[thread overview]
Message-ID: <55C8AEDC.90603@arm.com> (raw)
In-Reply-To: <20150804074116.GH25159@twins.programming.kicks-ass.net>

Hi,

On 04/08/15 08:41, Peter Zijlstra wrote:
> On Mon, Aug 03, 2015 at 07:30:32PM +0200, Frederic Weisbecker wrote:
>>> But you've forgotten about SCHED_DEADLINE, we count those in:
>>> rq->dl.dl_nr_running.
>>
>> Indeed. Hmm, there is no preemption between SCHED_DEALINE tasks, right?
>> So I can treat it like SCHED_FIFO.
> 
> Sadly no. Even though EDF has static job priority (once a job is
> activated its priority doesn't change anymore) DEADLINE also has a CBS
> component and that needs the tick regardless, even with a single task.
> 
> So any deadline task running means we cannot stop the tick.

Well, couldn't we stop it when we use hrtick? As start_hrtick_dl() sets
the hrtick to fire at tasks runtime depletion instant.

Thanks,

- Juri

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  reply	other threads:[~2015-08-10 14:01 UTC|newest]

Thread overview: 59+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-07-23 16:42 [PATCH 00/10] nohz: Tick dependency mask v2 Frederic Weisbecker
2015-07-23 16:42 ` [PATCH 01/10] nohz: Remove idle task special case Frederic Weisbecker
2015-07-23 16:42 ` [PATCH 02/10] nohz: Restart nohz full tick from irq exit Frederic Weisbecker
2015-07-23 16:42 ` [PATCH 03/10] nohz: Move tick_nohz_restart_sched_tick() above its users Frederic Weisbecker
2015-07-23 16:42 ` [PATCH 04/10] nohz: Remove useless argument on tick_nohz_task_switch() Frederic Weisbecker
2015-08-03 12:39   ` Peter Zijlstra
2015-08-03 12:49     ` Frederic Weisbecker
2015-08-03 13:04       ` Peter Zijlstra
2015-07-23 16:42 ` [PATCH 05/10] nohz: New tick dependency mask Frederic Weisbecker
2015-07-24 16:55   ` Chris Metcalf
2015-07-24 17:16     ` Frederic Weisbecker
2015-07-24 17:43       ` Chris Metcalf
2015-08-03 12:48         ` Peter Zijlstra
2015-08-03 12:43   ` Peter Zijlstra
2015-08-03 13:05     ` Frederic Weisbecker
2015-08-03 13:24       ` Peter Zijlstra
2015-08-03 13:49         ` Frederic Weisbecker
2015-08-03 12:57   ` Peter Zijlstra
2015-08-03 13:09     ` Frederic Weisbecker
2015-08-03 13:29       ` Peter Zijlstra
2015-08-03 13:55         ` Frederic Weisbecker
2015-08-03 14:11           ` Peter Zijlstra
2015-07-23 16:42 ` [PATCH 06/10] perf: Migrate perf to use new tick dependency mask model Frederic Weisbecker
2015-07-23 16:42 ` [PATCH 07/10] sched: Migrate sched " Frederic Weisbecker
2015-07-23 16:55   ` Frederic Weisbecker
2015-07-24 16:56   ` Chris Metcalf
2015-07-29 13:01     ` Frederic Weisbecker
2015-08-03 14:00   ` Peter Zijlstra
2015-08-03 14:50     ` Frederic Weisbecker
2015-08-03 17:09       ` Peter Zijlstra
2015-08-03 17:30         ` Frederic Weisbecker
2015-08-04  7:41           ` Peter Zijlstra
2015-08-10 14:02             ` Juri Lelli [this message]
2015-08-10 14:16               ` Frederic Weisbecker
2015-08-10 14:28                 ` Peter Zijlstra
2015-08-10 15:11                   ` Peter Zijlstra
2015-08-10 15:29                     ` Frederic Weisbecker
2015-08-10 15:43                       ` Juri Lelli
2015-08-10 16:41                       ` Peter Zijlstra
2015-08-10 15:33                 ` Christoph Lameter
2015-07-23 16:42 ` [PATCH 08/10] posix-cpu-timers: Migrate " Frederic Weisbecker
2015-07-24 16:57   ` Chris Metcalf
2015-07-29 13:23     ` Frederic Weisbecker
2015-07-29 17:24       ` Chris Metcalf
2015-07-30  0:44         ` Frederic Weisbecker
2015-07-30 14:31           ` Luiz Capitulino
2015-07-30 14:46             ` Frederic Weisbecker
2015-07-30 19:35           ` Chris Metcalf
2015-07-30 19:45             ` Frederic Weisbecker
2015-07-30 19:52               ` Chris Metcalf
2015-07-31 14:49                 ` Frederic Weisbecker
2015-08-03 15:59                   ` Chris Metcalf
2015-08-03 18:01                     ` Frederic Weisbecker
2015-08-03 17:12                   ` Peter Zijlstra
2015-08-03 17:39                     ` Frederic Weisbecker
2015-08-03 19:07                       ` Peter Zijlstra
2015-08-06 17:13                       ` Chris Metcalf
2015-07-23 16:42 ` [PATCH 09/10] sched-clock: " Frederic Weisbecker
2015-07-23 16:42 ` [PATCH 10/10] nohz: Remove task switch obsolete tick dependency check Frederic Weisbecker

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