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From: Thomas Gleixner <tglx@linutronix.de>
To: LKML <linux-kernel@vger.kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>,
	Dimitri Sivanich <sivanich@sgi.com>,
	Peter Zijlstra <peterz@infradead.org>,
	Ingo Molnar <mingo@elte.hu>
Subject: [patch 0/2] sched, timers: simplify calc_load and avoid cpu iteration loop
Date: Thu, 14 May 2009 11:21:14 -0000	[thread overview]
Message-ID: <20090514105915.973318588@linutronix.de> (raw)

Dimitri Sivanich pointed out that calc_load iterates over all online
CPUs under xtime lock which can cause long latencies on large SMP
systems.

The following patch series removes the iteration loop and lets
scheduler_tick() on each CPU update the number of active tasks. The
calc_load() function just uses this variable and updates avenrun from
do_timer().

Dimitri, can you please test run this on one of your large machines ?

Thanks,

	tglx



             reply	other threads:[~2009-05-14 11:22 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-05-14 11:21 Thomas Gleixner [this message]
2009-05-14 11:21 ` [patch 1/2] sched, timers: move calc_load() to scheduler Thomas Gleixner
2009-05-14 20:00   ` Peter Zijlstra
2009-05-14 20:40     ` Thomas Gleixner
2009-05-15  5:13       ` Peter Zijlstra
2009-05-14 11:21 ` [patch 2/2] sched, timers: cleanup avenrun users Thomas Gleixner
2009-05-14 17:23 ` [patch 0/2] sched, timers: simplify calc_load and avoid cpu iteration loop Dimitri Sivanich
2009-05-14 19:26   ` Thomas Gleixner
2009-05-15 12:23 ` Dimitri Sivanich

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