From: Dave Jones <davej@codemonkey.org.uk>
To: "Calin A. Culianu" <calin@ajvar.org>
Cc: Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: SMP Pentium4 -- PAUSE Instruction
Date: Tue, 3 Dec 2002 15:55:29 +0000 [thread overview]
Message-ID: <20021203155529.GA1622@suse.de> (raw)
In-Reply-To: <Pine.LNX.4.33L2.0212031029580.1780-100000@rtlab.med.cornell.edu>
On Tue, Dec 03, 2002 at 10:42:13AM -0500, Calin A. Culianu wrote:
>
> I as wondering -- according to Intel's docs they recommend that on a P4
> processor to use the PAUSE instruction (aka rep followed by a nop) inside
> any spin loop (such as one used in SMP spinlock code) in order to both
> improve processor performance and reduce power consumption.
> Is this instruction being used in spin-wait loops? For some reason, I am
> having a hard time figuring out whether or not it is being used. There is
> a rep_nop() in processor.h.. but I can't determine if that is being called
> for spin lock lock/unlock code.
there's also rep;nop in asm-i386/spinlock.h
See spin_lock_string()
Dave
--
| Dave Jones. http://www.codemonkey.org.uk
| SuSE Labs
next prev parent reply other threads:[~2002-12-03 15:50 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2002-12-03 15:42 SMP Pentium4 -- PAUSE Instruction Calin A. Culianu
2002-12-03 15:55 ` Dave Jones [this message]
2002-12-03 16:06 ` Arjan van de Ven
2002-12-03 17:21 ` Calin A. Culianu
-- strict thread matches above, loose matches on Subject: below --
2002-12-03 15:57 Nakajima, Jun
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