From: Matthew Garrett <mjg59@srcf.ucam.org>
To: Thomas Gleixner <tglx@linutronix.de>
Cc: LKML <linux-kernel@vger.kernel.org>,
Arjan van de Ven <arjan@infradead.org>,
Peter Zijlstra <peterz@infradead.org>
Subject: Re: [PATCH] hrtimers: Special-case zero length sleeps
Date: Wed, 15 Feb 2012 20:38:14 +0000 [thread overview]
Message-ID: <20120215203814.GA29795@srcf.ucam.org> (raw)
In-Reply-To: <alpine.LFD.2.02.1202152125500.2794@ionos>
On Wed, Feb 15, 2012 at 09:30:20PM +0100, Thomas Gleixner wrote:
> On Wed, 15 Feb 2012, Matthew Garrett wrote:
> > Excellent. So the real question is what /should/ sleep(0) do - nothing,
> > schedule or sleep for an arbitrary period of time that could be years?
>
> Well, I don't expect slack to be set to years and I really don't want
> to special case sleep(0), because then we might end up discussing
> special casing usleep(1) or nanosleep(1ns) as well.
Increasing slack to the seconds range has measureable power management
benefits, but there's some code that ends up broken as a result even
when they're nominally event driven. I've no problem with us just
declaring that code as broken, but it would be less effort to special
case it. Application authors do seem to have ended up under the belief
that sleep(0) is a meaningful thing to do, and the internet seems to be
full of suggestions to use it rather than sched_yield().
--
Matthew Garrett | mjg59@srcf.ucam.org
next prev parent reply other threads:[~2012-02-15 20:38 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-09-29 14:59 [PATCH] hrtimers: Special-case zero length sleeps Matthew Garrett
2012-02-15 14:40 ` Thomas Gleixner
2012-02-15 14:52 ` Matthew Garrett
2012-02-15 20:14 ` Thomas Gleixner
2012-02-15 20:22 ` Matthew Garrett
2012-02-15 20:30 ` Thomas Gleixner
2012-02-15 20:38 ` Matthew Garrett [this message]
2012-02-15 20:40 ` Peter Zijlstra
2012-02-15 20:43 ` Matthew Garrett
2012-02-15 20:46 ` Thomas Gleixner
2012-02-15 20:47 ` Matthew Garrett
2012-02-16 14:27 ` Matthew Garrett
2012-02-16 14:31 ` Alan Cox
2012-02-16 14:51 ` Peter Zijlstra
2012-02-16 15:01 ` Matthew Garrett
2012-02-16 19:09 ` Thomas Gleixner
2012-02-15 14:54 ` Peter Zijlstra
2012-02-15 14:58 ` Matthew Garrett
2012-02-15 20:22 ` Thomas Gleixner
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