From: Peter Zijlstra <peterz@infradead.org>
To: stephan.baerwolf@tu-ilmenau.de
Cc: linux-kernel@vger.kernel.org, Ingo Molnar <mingo@elte.hu>,
ncrao@google.com, Mike Galbraith <efault@gmx.de>
Subject: Re: sched: fix/optimise some issues
Date: Wed, 20 Jul 2011 21:11:30 +0200 [thread overview]
Message-ID: <1311189090.29152.73.camel@twins> (raw)
In-Reply-To: <4E26DB41.9070002@tu-ilmenau.de>
On Wed, 2011-07-20 at 15:42 +0200, Stephan Bärwolf wrote:
> In "check_preempt_tick()" (kernel/sched_fair.c:1093) a ulong
> called "ideal_runtime" stores a timeslice of the current task
> (scheduling entity). This time complies real cpu-time.
>
> At the end of the same function (nr_running > 1) this (real) time
> is compared with a virtual-runtime-delta. Obviously the timeunits
> (real vs. virtual) didn't fit.
>
> Using "wakeup_preempt_entity()" instead should fix this in a even
> more general way.
Hrm,. I'm fairly sure we did that on purpose and the thing that is
missing is a big fat comment. People keep trying to fix that (me
included).
I'll try and dig up the why and such.
next prev parent reply other threads:[~2011-07-20 19:11 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-07-20 13:42 sched: fix/optimise some issues Stephan Bärwolf
2011-07-20 19:11 ` Peter Zijlstra [this message]
2011-07-21 1:00 ` Mike Galbraith
2011-07-20 19:11 ` Peter Zijlstra
2011-07-20 19:11 ` Peter Zijlstra
2011-07-21 15:08 ` Peter Zijlstra
2011-07-21 16:36 ` Stephan Bärwolf
2011-07-21 16:32 ` Peter Zijlstra
2011-07-21 16:43 ` Peter Zijlstra
2011-07-21 16:51 ` Peter Zijlstra
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