Re: Pentium 4 and 2.4/2.5

From: Frank Davis (fdavis112@juno.com)
Date: Sat Nov 04 2000 - 19:04:08 EST


Alan,
  As for 'rep nop', couldn't we add in the code, as an example:
#ifdef Pentium_4
rep nop
#endif

  As for the 2.2.18 patch for correctly determining 2GHz and above, can
it be easily merged into the 2.4.x kernel, and if so, what's the maximum
clock speed that can be detected?

Regards,
-Frank

On Tue, 7 Nov 2000 21:48:40 +0000 (GMT) Alan Cox
<alan@lxorguk.ukuu.org.uk> writes:
> > are you saying that rep;nop is not needed in the spinlocks?
> (because they
> > are for P4)
>
> rep;nop is a magic instruction on the PIV and possibly some PIII
> series CPUs
> [not sure]. As far as I can make out it naps momentarily or until
> bus
> activity thus saving power on spinlocks.
>
> The problem is 'rep nop' is not defined on other cpus so we can only
> really use
> it on the PIII/PIV kernel builds
>
-
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