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From: Peter Zijlstra <peterz@infradead.org>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: 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>, Mike Galbraith <efault@gmx.de>
Subject: Re: [RFC patch 1/2] sched: dynamically adapt granularity with nr_running
Date: Sat, 11 Sep 2010 22:36:20 +0200	[thread overview]
Message-ID: <1284237380.2251.56.camel@laptop> (raw)
In-Reply-To: <AANLkTin0LOuTOcJPiZcZGeZMdqsy2dohyrREw2GGhddJ@mail.gmail.com>

On Sat, 2010-09-11 at 12:21 -0700, Linus Torvalds wrote:
> On Sat, Sep 11, 2010 at 11:57 AM, Peter Zijlstra <peterz@infradead.org> wrote:
> >
> > Not at all charmed, this look like random changes without conceptual
> > integrity.
> 
> I wish people actually looked at the _numbers_ and reacted to them,
> rather than argue theory.
> 
> Guys, we have cases of bad latency under load. That's a pretty
> undeniable fact. Arguing against a patch because of some theoretical
> issue without at all even acknowledging the latency improvements is, I
> think, really bad form.
> 
> So please. Acknowledge the latency issue. And come up with better
> patches, rather than just shoot down alternatives. Because if the
> answer is just NAK with no alternative, then that answer is worthless.
> No?

>From what I can make up:

  LAT=`cat /proc/sys/kernel/sched_latency_ns`; 
  echo $((LAT/8)) > /proc/sys/kernel/sched_min_granularity_ns

will give you pretty much the same result as Mathieu's patch.

But if you want us to change the scheduler to be more latency sensitive
and trade in throughput for other benchmarks, we can do that.

  reply	other threads:[~2010-09-11 20:36 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 [this message]
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
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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