From: Pavel Machek <pavel@suse.cz>
To: Matthew Wilcox <matthew@wil.cx>
Cc: Andrew Patterson <andrew.patterson@hp.com>,
linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org,
shaohua.li@intel.com
Subject: Re: [PATCH] ASPM: Use msleep instead of cpu_relax during link retraining
Date: Fri, 26 Dec 2008 19:27:02 +0100 [thread overview]
Message-ID: <20081226182702.GA1528@ucw.cz> (raw)
In-Reply-To: <20081225232427.GJ19967@parisc-linux.org>
On Thu 2008-12-25 16:24:27, Matthew Wilcox wrote:
> On Thu, Dec 25, 2008 at 08:01:29PM +0100, Pavel Machek wrote:
> > On Mon 2008-12-22 15:11:57, Andrew Patterson wrote:
> > > ASPM: Use msleep instead of cpu_relax during link retraining
> > >
> > > The cpu_relax() function can be a noop on certain architectures
> > > like IA-64 when CPU threads are disabled, so use msleep instead
> > > during link retraining busy/wait loop.
> >
> > Author clearly wanted to do a busy loop... why do you think 10msec
> > delay here is acceptable?
>
> 10ms? I see a 1ms sleep.
Yes... IIRC msleep will sleep for up-to 1/HZ on non-highres systems.
> Yes, the subsequent test should be of reg16 instead of jiffies.
Thanks.
Pavel
--
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
next prev parent reply other threads:[~2008-12-26 18:27 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-12-22 22:11 [PATCH] ASPM: Use msleep instead of cpu_relax during link retraining Andrew Patterson
2008-12-25 19:01 ` Pavel Machek
2008-12-25 23:24 ` Matthew Wilcox
2008-12-26 18:27 ` Pavel Machek [this message]
2009-01-05 19:17 ` Jesse Barnes
2009-01-05 19:40 ` Andrew Patterson
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