From: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
To: LKML <linux-kernel@vger.kernel.org>,
Peter Zijlstra <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
Andrew Morton <akpm@linux-foundation.org>,
Ingo Molnar <mingo@elte.hu>, Steven Rostedt <rostedt@goodmis.org>,
Thomas Gleixner <tglx@linutronix.de>,
Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
Tony Lindgren <tony@atomide.com>, Mike Galbraith <efault@gmx.de>
Subject: [RFC patch 0/2] sched: dynamically adapt granularity with nr_running
Date: Sat, 11 Sep 2010 13:37:32 -0400 [thread overview]
Message-ID: <20100911173732.551632040@efficios.com> (raw)
Changing the minimum granularity is a double-edged sword: if we set it to a too
small value, then the scheduler will preempt tasks too often. If it is too
large, then the "latency" period can grow very large as the number of running
tasks increases.
The first patch leaves the same scheduling granularity when there are few tasks
on the system (3 or less), but dynamically adapts (shrinks) the sched
granularity when there are more. At a ceiling value of 8 running tasks (this
choice is arbitrary), it grows the latency rather than shrinking granularity
further to ensure we don't end up calling the scheduler too often.
The second patch ensures that awakened sleeping tasks don't get affected by
shrinked minimum granularity.
Comments are welcome,
Thanks,
Mathieu
--
Mathieu Desnoyers
Operating System Efficiency R&D Consultant
EfficiOS Inc.
http://www.efficios.com
next reply other threads:[~2010-09-11 17:40 UTC|newest]
Thread overview: 76+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-09-11 17:37 Mathieu Desnoyers [this message]
2010-09-11 17:37 ` [RFC patch 1/2] sched: dynamically adapt granularity with nr_running 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
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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