From: j.neuschaefer@gmx.net (Jonathan Neuschäfer)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH] arch/arm/kernel: use cpu_relax() in halt loops
Date: Wed, 15 Dec 2010 00:00:01 +0100 [thread overview]
Message-ID: <20101214230001.GA1747@debian.debian> (raw)
In-Reply-To: <20101214225126.GD24303@n2100.arm.linux.org.uk>
On Tue, Dec 14, 2010 at 10:51:26PM +0000, Russell King - ARM Linux wrote:
> On Tue, Dec 14, 2010 at 11:48:48PM +0100, Jonathan Neusch?fer wrote:
> > Looking throught arch/arm/kernel/ I found some halt loops.
> > I just thought we could save some power here using cpu_relax(),
> > or am I missing something?
>
> #if __LINUX_ARM_ARCH__ == 6
> #define cpu_relax() smp_mb()
> #else
> #define cpu_relax() barrier()
> #endif
>
> IOW, it's either a memory barrier or compiler barrier on ARM; it
> doesn't do any power saving.
Okay, thanks for that explanation.
next prev parent reply other threads:[~2010-12-14 23:00 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-12-14 22:48 [PATCH] arch/arm/kernel: use cpu_relax() in halt loops Jonathan Neuschäfer
2010-12-14 22:51 ` Russell King - ARM Linux
2010-12-14 23:00 ` Jonathan Neuschäfer [this message]
-- strict thread matches above, loose matches on Subject: below --
2010-11-27 20:20 Jonathan Neuschäfer
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