From: William Lee Irwin III <wli@holomorphy.com>
To: Peter Williams <pwil3058@bigpond.net.au>
Cc: Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Michal Kaczmarski <fallow@op.pl>,
Shane Shrybman <shrybman@aei.ca>
Subject: Re: [PATCH] V-3.0 Single Priority Array O(1) CPU Scheduler Evaluation
Date: Tue, 3 Aug 2004 18:51:15 -0700 [thread overview]
Message-ID: <20040804015115.GF2334@holomorphy.com> (raw)
In-Reply-To: <41103DBB.6090100@bigpond.net.au>
William Lee Irwin III wrote:
>> Aperiodic rotations defer movement until MAX_RT_PRIO's slot is evacuated.
On Wed, Aug 04, 2004 at 11:36:59AM +1000, Peter Williams wrote:
> Unfortunately, to ensure no starvation, promotion has to continue even
> when there are tasks in MAX_RT_PRIO's slot.
One may either demote to evict MAX_RT_PRIO immediately prior to
rotation or rely on timeslice expiry to evict MAX_RT_PRIO. Forcibly
evicting MAX_RT_PRIO undesirably accumulates tasks at the fencepost.
William Lee Irwin III wrote:
>> The primary concern was that ticklessness etc. may require it to occur
>> during context switches.
On Wed, Aug 04, 2004 at 11:36:59AM +1000, Peter Williams wrote:
> On a tickless system, I'd consider using a timer to control when
> do_promotions() gets called. I imagine something similar will be
> necessary to manage time slices?
This is an alternative to scheduler accounting in context switches.
Periodicity often loses power conservation benefits.
-- wli
next prev parent reply other threads:[~2004-08-04 1:51 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2004-08-02 6:31 [PATCH] V-3.0 Single Priority Array O(1) CPU Scheduler Evaluation Peter Williams
2004-08-02 13:42 ` William Lee Irwin III
2004-08-03 0:33 ` Peter Williams
2004-08-03 2:03 ` William Lee Irwin III
2004-08-03 3:39 ` Peter Williams
2004-08-03 10:49 ` William Lee Irwin III
2004-08-04 0:37 ` Peter Williams
2004-08-04 0:50 ` William Lee Irwin III
2004-08-04 1:36 ` Peter Williams
2004-08-04 1:51 ` William Lee Irwin III [this message]
2004-08-04 2:40 ` Peter Williams
2004-08-04 7:05 ` Ingo Molnar
2004-08-04 7:44 ` William Lee Irwin III
2004-08-05 1:06 ` Peter Williams
2004-08-05 2:00 ` William Lee Irwin III
2004-08-05 2:12 ` Peter Williams
[not found] <2oEEn-197-9@gated-at.bofh.it>
2004-08-02 13:27 ` Andi Kleen
2004-08-03 0:27 ` Peter Williams
2004-08-03 3:53 ` Andrew Morton
2004-08-03 4:38 ` Peter Williams
2004-08-03 6:51 ` Andi Kleen
-- strict thread matches above, loose matches on Subject: below --
2004-08-07 1:44 Peter Williams
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