Subject: Re: Floating point in the kernel
To: None <is@jocelyn.rhein.de, jonathan@DSG.Stanford.EDU>
From: Ross Harvey <ross@teraflop.com>
List: tech-kern
Date: 09/18/1998 17:24:40
> From: Jonathan Stone <jonathan@DSG.Stanford.EDU>
>
>
>
> [latency vs throughput]
>
> Exactly, I was just writing the same thing.  You have to compare both
> time to complete, and how long the unit blocks before it can issue
> another insn.
>
> >In my Usenet archives, I found the following table of fixed point multiply
> >latencies and throughputs, posted on comp.arch in 1996 by
> John Carr <jfc@mit.edu>:
>
> [snip]
>
> >In my opinion, this _is_ bad.  Particularly the Alpha.    They have
> >improved since then, but then so has floating point performance.
>
> Huh?  21064s are pretty old, but. even so, the raw clockrate was
> higher than many other CPus of the same vintage. Overall, FP
> performance wasn't so bad.
>


Heh, I agree, that table was pretty funny. There are lies, damned lies,
and statistics. :-)

Comparing clock counts between 25 MHz and 275 MHz cpu units....cute....

  --Ross Harvey