From: Russell King - ARM Linux <linux@arm.linux.org.uk>
To: "Jonathan Neuschäfer" <j.neuschaefer@gmx.net>
Cc: linux-kernel@vger.kernel.org,
Nicolas Pitre <nicolas.pitre@linaro.org>,
Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will.deacon@arm.com>,
Kevin Hilman <khilman@deeprootsystems.com>,
Tony Lindgren <tony@atomide.com>,
Jeremy Kerr <jeremy.kerr@canonical.com>,
Eric Miao <eric.y.miao@gmail.com>,
linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH] arch/arm/kernel: use cpu_relax() in halt loops
Date: Tue, 14 Dec 2010 22:51:26 +0000 [thread overview]
Message-ID: <20101214225126.GD24303@n2100.arm.linux.org.uk> (raw)
In-Reply-To: <20101214224848.GA1706@debian.debian>
On Tue, Dec 14, 2010 at 11:48:48PM +0100, Jonathan Neuschäfer 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.
next prev parent reply other threads:[~2010-12-14 22:51 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-12-14 22:48 Jonathan Neuschäfer
2010-12-14 22:51 ` Russell King - ARM Linux [this message]
2010-12-14 23:00 ` Jonathan Neuschäfer
-- strict thread matches above, loose matches on Subject: below --
2010-11-27 20:20 Jonathan Neuschäfer
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