Subject: Re: probing CPU speed?
To: None <>
From: Peter Bentley <>
List: port-i386
Date: 11/20/1998 10:55:49 wrote:
>On 18 Nov 1998, Chris G. Demetriou wrote:
> > Who _cares_ what the raw CPU speed is?  It's at best useless, at worst
> > seriously deceptive...
> Well, it's not useless, but I do agree that it can be deceptive because
> getting a precise measurement can be tricky (or so it would appear from
> the comments I've read in mhz.c).
> anyway, here is an example of how I have found the mhz program (which
> prints what it thinks is the CPU speed) to be useful: [measuring
> CPU speed to decide on how to distribute RC5 cracking]

As cgd said, why would you care about raw CPU MHz speed for that?  You
wanna know which boxes crack RC5 fastest? Crack some keys on 'em and use
*that* as your relative performance benchmark.  It'll be a sight more
representative than raw CPU speed.  

The deceptiveness has nothing to do with the difficulty of obtaining
accurate MHz numbers, it's because you're measuring something totally
different.  For load balancing calculations, even a trivial userland
benchmark like Dhrystone is probably better than CPU speed.  Some sample
figures from the actual application you want to run are always going to
be better though...