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From: guy@gorodish.UUCP
Newsgroups: comp.arch,comp.lang.c
Subject: Re: Tuning your libraries for your machine
Message-ID: <16293@sun.uucp>
Date: Tue, 7-Apr-87 13:07:11 EST
Article-I.D.: sun.16293
Posted: Tue Apr  7 13:07:11 1987
Date-Received: Sat, 11-Apr-87 00:36:00 EST
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Reply-To: guy@sun.UUCP (Guy Harris)
Organization: Sun Microsystems, Mountain View
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Xref: utgpu comp.arch:807 comp.lang.c:1507

>A simple but common logic flaw in my opinion.  Granted that it can require
>up to 15 or 20 times the effort to support 15 or 20 models, but the issue is
>whether any such model is worth added support.

Do you know of any major vendor who *does* provide that kind of
support?  Does DEC provide different versions of the VMS libraries
for different VAX models?  Does IBM provide different versions of the
MVS libraries for different 370 models?

>But John Gilmore seems to be saying: "IBM was selling thousands of machines
>a month so the only sensible thing was to move my product to a company whose
>market was so small they wouldn't confuse me with multiple models."

John is obviously NOT saying anything even remotely resembling that.
Show me where he said *anything* about *moving* his product from an
IBM machine.  He's merely saying that it wasn't worth the effort
producing N versions of the APL system for N different IBM 370
models.

>The user doesn't demand a general solution.  He just doesn't like his
>application running 20 times slower than necessary.  The plain fact is that
>major savings can result from optimizing a few routines (strcpy, ldiv being
>good examples).

OK, show me a plain fact that indicates that, for anybody supplying
large volumes of some software package, you can get a 20X speed up by
tweaking the code for different models of a line of machines (not
"tweaking the code for machines with or without a given hardware
option", but "tweaking the code for different models of a line of
machines" - e.g., a VAX-11/780, VAX 8600, and VAX 8200, or a 370/168,
3033, 4381, and 3090).

>> These should both be done automatically by a good compiler....
>
>"should be" but not necessarily "is".  There are some *really pathetic*
>compilers out there.

OK, are the compilers in question "pathetic" or "good"?  They can't
be both....