From: Arjan van de Ven <arjan@infradead.org>
To: Rene Herman <rene.herman@keyaccess.nl>
Cc: David Woodhouse <dwmw2@infradead.org>,
linux-kernel@vger.kernel.org,
Thomas Gleixner <tglx@linutronix.de>, Ingo Molnar <mingo@elte.hu>,
Stephen Hemminger <shemminger@vyatta.com>
Subject: Re: [RFC] Imprecise timers.
Date: Tue, 22 Jul 2008 05:54:21 -0700 [thread overview]
Message-ID: <20080722055421.2023d261@infradead.org> (raw)
In-Reply-To: <488589E6.5070300@keyaccess.nl>
On Tue, 22 Jul 2008 09:19:02 +0200
Rene Herman <rene.herman@keyaccess.nl> wrote:
> On 22-07-08 05:02, David Woodhouse wrote:
>
> > Many users of timers don't really care too much about exactly when
> > their timer fires -- and waking a CPU to satisfy such a timer is a
> > waste of power. This patch implements a 'range' timer which will
> > fire at a 'convenient' moment within given constraints.
> >
> > It's implemented by a deferrable timer at the beginning of the
> > range, which will run some time later when the CPU happens to be
> > awake. And a non-deferrable timer at the hard deadline, to ensure
> > it really does happen by then.
>
> Are there actually users for this (not just in theory)? The
> deferrable timer sort of sounds like all I'd ever want if I, as you
> say, wouldn't really care...
there's a few; mostly around hardware timeout..For example Stephen want
it for his drivers.
EXT3 journal flushing is another one where we can easily say
"between 4 and 7 seconds" rather than "exactly at 5"
--
If you want to reach me at my work email, use arjan@linux.intel.com
For development, discussion and tips for power savings,
visit http://www.lesswatts.org
next prev parent reply other threads:[~2008-07-22 12:54 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-07-22 3:02 [RFC] Imprecise timers David Woodhouse
2008-07-22 3:05 ` [RFC] schedule_timeout_range() David Woodhouse
2008-07-22 3:56 ` Nick Piggin
2008-07-22 4:12 ` David Woodhouse
2008-07-22 4:26 ` Arjan van de Ven
2008-07-22 4:34 ` David Woodhouse
2008-07-22 4:33 ` Nick Piggin
2008-07-22 4:45 ` David Woodhouse
2008-07-22 4:50 ` Nick Piggin
2008-07-22 4:58 ` David Woodhouse
2008-07-22 5:35 ` Jan Engelhardt
2008-07-22 4:33 ` Arjan van de Ven
2008-07-22 7:19 ` [RFC] Imprecise timers Rene Herman
2008-07-22 12:54 ` Arjan van de Ven [this message]
2008-07-22 14:04 ` Rene Herman
2008-07-29 0:36 ` Pallipadi, Venkatesh
2008-08-09 12:54 ` Pavel Machek
2008-08-11 17:35 ` Venki Pallipadi
2008-08-12 12:00 ` Pavel Machek
2008-08-12 18:11 ` Venki Pallipadi
2008-08-12 21:55 ` Alan Cox
2008-08-12 21:58 ` Pavel Machek
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