Re: [Q] Implementation of spin_lock on i386: why "rep;nop" ?

From: Jonathan Lundell (jlundell@pobox.com)
Date: Mon Sep 17 2001 - 12:06:21 EST

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At 12:42 PM -0400 2001-09-17, Richard B. Johnson wrote:
> > What is the intent behind this "rep;nop" ? Does it really rely on an
> > undocumented behaviour ?
>
>Well it's now documented although you have to search a web-site to
>find it. Basically, it runs the CPU at low clock-speed when it's
>busy-waiting. Since most all spin-locks lock for mere microseconds
>it's unlikely that it does anything useful, but it can't hurt.

Sounds like a good opportunity for a comment....

-- 
/Jonathan Lundell.
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