*BSD News Article 22384


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From: torvalds@klaava.Helsinki.FI (Linus Torvalds)
Newsgroups: comp.os.386bsd.misc,comp.os.linux
Subject: Re: FYI.. benchmarks on linux and 386bsd
Date: 14 Oct 1993 11:58:22 +0200
Organization: University of Helsinki
Lines: 33
Message-ID: <29j7ru$bfs@klaava.Helsinki.FI>
References: <CEMA3n.DuE@rex.uokhsc.edu> <1993Oct9.191335.3202@Belvedere%hip-hop.suvl.ca.us> <1993Oct13.132032.22762@swan.pyr> <jpo.750590731@hrz.tu-chemnitz.de>
NNTP-Posting-Host: klaava.helsinki.fi

In article <jpo.750590731@hrz.tu-chemnitz.de>,
Joerg Pommnitz <jpo@kappa.informatik.tu-chemnitz.de> wrote:
>iiitac@swan.pyr (Alan Cox) writes:
>
>>>One thing I'd like to point out that in my particular experience,
>>>floating-point sans coprocessor on 386BSD was miserably slow in
>>>comparison to Linux.  I tried a whetstone benchmark and it took over
>>This is odd. They use the same coprocessor emulator.
>
>No, they don't.
>
>Bill Metzenhen (sp ?) has donated his FPUEmu to Linux. This code is much
>better than the original emulator from Linus.

Amen to that one, brother.  The original linux math emulation was
written by me as a stopgap measure to get gcc working without any diffs
om machines without co-processors so that somebody else could handle the
gcc port (and somebody else did: hlu/hjl has done an admirable job, and
I've been able to ignore compiler/library issues ever since). 

The current one is a totally rewritten emulator by Bill Metzenthen, and
is much faster as well as being *much* closer to the real thing.  I
dumped my original emulator the day I got Bill's - I'm not so proud that
I don't know a good thing when I see it (and it has only gotten better). 

I assume the 386BSD crowd are still using my original emulator due to
copyright reasons (I waived the GPL for that one, and made it "freely
available for the 386bsd project" or whatever).  It's much slower, and
doesn't emulate all the instructions unless somebody else has worked
hard on it.  And even the instructions it does emulate it doesn't do
completely: the math never checks for overflows or NaN's etc. 

			Linus