Message-ID: <19990604191004.03394@atrey.karlin.mff.cuni.cz>
Date: Fri, 4 Jun 1999 19:10:04 +0200
From: Jan Hubicka <hubicka AT atrey DOT karlin DOT mff DOT cuni DOT cz>
To: pgcc AT delorie DOT com
Subject: Re: Performance of Krzysztof program
References: <m10pUEy-001mHUC AT Dirac DOT Chemie DOT FU-Berlin DOT DE> <375690F1 DOT 6611C009 AT cadvision DOT com> <3757DE74 DOT F40365A5 AT pppl DOT gov>
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In-Reply-To: <3757DE74.F40365A5@pppl.gov>; from Dan Melomedman on Fri, Jun 04, 1999 at 10:11:00AM -0400
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> Rob Somerville wrote:
> 
> > any chance VC6.0 is linking against optimized libraries? I had same problem
> > with Sunsoft SPARC compilers vs. EGCS, but found the issue was Special libraries that
> > Sunsoft compilers used for certain optimization settings ( -fast )
> >
> > -bob
> 
> I bet they do! For example on PPC machines you can link with libmoto, provided by
> motorola which is a substitute for standard C math and string functions, the thing is
> hand-optimized assembly code, on PPC Linux this gives at least 2X improvement in
> nbench.  Maybe Intel has  something like that on their site? Check out:
> http://www.mot.com/SPS/PowerPC/library/fact_sheet/libmoto_ts.html
Glibc actually comes with __math.h that contains fast inlines for most popular math
functions. Also string functions are pretty well hand optimized, so I think Linux
libraries are not bad...
I think that VC6.0 is much stronger in the register allocation and scheduling.
I don't know much about other VC6.0 optimizations, but I think these two are most
important.

Honza

-- 
                       OK. Lets make a signature file.
+-------------------------------------------------------------------------+
|        Jan Hubicka (Jan Hubi\v{c}ka in TeX) hubicka AT freesoft DOT cz         |
|         Czech free software foundation: http://www.freesoft.cz          |
|AA project - the new way for computer graphics - http://www.ta.jcu.cz/aa |
|  homepage: http://www.paru.cas.cz/~hubicka/, games koules, Xonix, fast  |
|  fractal zoomer XaoS, index of Czech GNU/Linux/UN*X documentation etc.  | 
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