From: Peter Zijlstra <peterz@infradead.org>
To: Mike Galbraith <efault@gmx.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
LKML <linux-kernel@vger.kernel.org>,
Andrew Morton <akpm@linux-foundation.org>,
Ingo Molnar <mingo@elte.hu>, Steven Rostedt <rostedt@goodmis.org>,
Thomas Gleixner <tglx@linutronix.de>,
Tony Lindgren <tony@atomide.com>
Subject: Re: [RFC patch 1/2] sched: dynamically adapt granularity with nr_running
Date: Mon, 13 Sep 2010 10:41:35 +0200 [thread overview]
Message-ID: <1284367295.2275.31.camel@laptop> (raw)
In-Reply-To: <1284352547.7321.51.camel@marge.simson.net>
On Mon, 2010-09-13 at 06:35 +0200, Mike Galbraith wrote:
> On Sun, 2010-09-12 at 11:06 +0200, Peter Zijlstra wrote:
> > On Sat, 2010-09-11 at 13:48 -0700, Linus Torvalds wrote:
>
> > > And I don't like how you dismissed the measured latency improvement.
> > > And yes, I do think latency matters. A _lot_.
> >
> > OK, we'll make it better and sacrifice some throughput, can do, no
> > problem.
>
> I'm not seeing high wakeup latencies, even under hefty load. Mathieu's
> testcase is bad, but apparently solely due to START_DEBIT placement.
> That's kind of a sticky wicket. I've shot it in the heart before, but
> regretted doing so when I looked at kbuild vs static load fairness.
Yeah, without it you can starve the already running task on massive
forks.
Still, I'm not quite sure why people really care about fork() on time
sensitive paths, its a very expensive thing to do, pre-fork() and wake
when you need it, is what I would say.
next prev parent reply other threads:[~2010-09-13 8:41 UTC|newest]
Thread overview: 76+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-09-11 17:37 [RFC patch 0/2] sched: dynamically adapt granularity with nr_running Mathieu Desnoyers
2010-09-11 17:37 ` [RFC patch 1/2] " Mathieu Desnoyers
2010-09-11 18:57 ` Peter Zijlstra
2010-09-11 19:21 ` Linus Torvalds
2010-09-11 20:36 ` Peter Zijlstra
2010-09-11 20:45 ` Peter Zijlstra
2010-09-11 20:52 ` Linus Torvalds
2010-09-12 9:07 ` Peter Zijlstra
2010-09-11 20:48 ` Linus Torvalds
2010-09-12 9:06 ` Peter Zijlstra
2010-09-12 9:14 ` Peter Zijlstra
2010-09-12 20:39 ` Mathieu Desnoyers
2010-09-13 12:54 ` Peter Zijlstra
2010-09-12 20:34 ` Mathieu Desnoyers
2010-09-13 12:53 ` Peter Zijlstra
2010-09-13 4:35 ` Mike Galbraith
2010-09-13 8:41 ` Peter Zijlstra [this message]
2010-09-13 11:22 ` Ingo Molnar
2010-09-13 13:52 ` Steven Rostedt
2010-09-13 13:54 ` Peter Zijlstra
2010-09-13 14:02 ` Peter Zijlstra
2010-09-13 14:21 ` Ingo Molnar
2010-09-11 20:52 ` Mathieu Desnoyers
2010-09-11 19:57 ` Mathieu Desnoyers
2010-09-12 10:41 ` Peter Zijlstra
2010-09-12 20:37 ` Mathieu Desnoyers
2010-09-13 12:53 ` Peter Zijlstra
2010-09-13 13:15 ` Peter Zijlstra
2010-09-13 13:56 ` Mathieu Desnoyers
2010-09-13 14:16 ` Peter Zijlstra
2010-09-13 14:43 ` Steven Rostedt
2010-09-13 15:25 ` Mathieu Desnoyers
2010-09-13 15:39 ` Steven Rostedt
2010-09-13 16:16 ` [RFC PATCH] check_preempt_tick should not compare vruntime with wall time Mathieu Desnoyers
2010-09-13 16:36 ` Linus Torvalds
2010-09-13 17:45 ` Mathieu Desnoyers
2010-09-13 17:51 ` Linus Torvalds
2010-09-13 18:01 ` Mathieu Desnoyers
2010-09-13 18:10 ` Steven Rostedt
2010-09-13 18:03 ` Ingo Molnar
2010-09-13 18:19 ` Mathieu Desnoyers
2010-09-13 18:23 ` [PATCH] sched: Improve latencies under load by decreasing minimum scheduling granularity Ingo Molnar
2010-09-13 18:28 ` Joe Perches
2010-09-13 19:44 ` Linus Torvalds
2010-09-13 20:00 ` Ingo Molnar
2010-09-13 18:19 ` [RFC PATCH] check_preempt_tick should not compare vruntime with wall time Ingo Molnar
2010-09-13 17:36 ` Ingo Molnar
2010-09-13 17:56 ` Mathieu Desnoyers
2010-09-14 2:10 ` Mike Galbraith
2010-09-13 14:44 ` [RFC patch 1/2] sched: dynamically adapt granularity with nr_running Mike Galbraith
[not found] ` <1284386179.10436.6.camel@marge.simson.net>
2010-09-13 15:53 ` Peter Zijlstra
2010-09-13 18:04 ` [RFC][PATCH] sched: Improve tick preemption Peter Zijlstra
2010-09-14 2:27 ` [RFC patch 1/2] sched: dynamically adapt granularity with nr_running Mike Galbraith
2010-09-12 6:14 ` Ingo Molnar
2010-09-12 7:21 ` Mike Galbraith
2010-09-12 18:16 ` Mathieu Desnoyers
2010-09-13 4:13 ` Mike Galbraith
2010-09-13 6:41 ` Ingo Molnar
2010-09-13 7:08 ` Mike Galbraith
2010-09-13 7:35 ` Mike Galbraith
2010-09-13 8:35 ` Peter Zijlstra
2010-09-13 9:16 ` Mike Galbraith
2010-09-13 9:37 ` Peter Zijlstra
2010-09-13 9:50 ` Mike Galbraith
2010-09-13 9:55 ` Peter Zijlstra
2010-09-13 10:06 ` Mike Galbraith
2010-09-13 10:45 ` Peter Zijlstra
2010-09-13 11:43 ` Peter Zijlstra
2010-09-13 11:49 ` Peter Zijlstra
2010-09-13 12:32 ` Mike Galbraith
2010-09-13 20:19 ` Mathieu Desnoyers
2010-09-13 20:56 ` Mathieu Desnoyers
2010-09-12 18:13 ` Mathieu Desnoyers
2010-09-12 23:44 ` Mathieu Desnoyers
2010-09-11 17:37 ` [RFC patch 2/2] sched: sleepers coarse granularity on wakeup Mathieu Desnoyers
2010-09-12 12:44 ` [RFC patch 0/2] sched: dynamically adapt granularity with nr_running Peter Zijlstra
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