Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!cornell!uw-beaver!rice!sun-spots-request
From: felix!arcturus!dav@hplabs.hp.com (David L. Markowitz)
Newsgroups: comp.sys.sun
Subject: Re: libm for 68881 and Sun fpa is incredibly slow
Keywords: Software
Message-ID: <4423@arcturus>
Date: 6 May 89 14:37:31 GMT
References: <8903222320.AA01458@bayes.arc.nasa.gov>
Sender: usenet@rice.edu
Organization: Rockwell International, Anaheim, CA
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Approved: Sun-Spots@rice.edu
Original-Date: 21 Apr 89 18:46:30 GMT
X-Sun-Spots-Digest: Volume 7, Issue 272, message 11 of 19

self@bayes.arc.nasa.gov (Matthew Self) writes:
> John Schultz compiled the following timings for Sun's math libraries using
> GCC and CC with various options:
> 
> > My results, running on Sun 3/60, Sun OS 3.5, GNU CC 1.32 built using
> > default switches were
> > 
[gcc timings deleted]
> > cc -lm                   === 159.4 real       146.7 user         0.6 sys
> > cc -O -lm                === 155.4 real       146.2 user         0.4 sys
> > cc -f68881 -lm           ===   6.6 real         4.6 user         0.1 sys 
                                            Is this ^^^ a Typo?  Maybe 6.4?
> > cc  /usr/lib/f68881.il   ===   9.9 real         6.7 user         0.1 sys
> > cc -O /usr/lib/f68881.il ===   6.5 real         6.4 user         0.0 sys 
[program deleted]
> 
[discussion about GCC inline library reducing user time to 2.5s deleted]

I would like to point out an error in the timing tests done above.  The
inline expansions only help in math library function calls - not in
built-in floating point operations (like * and /).  The -f68881 option
does the opposite - it helps built-in math, but not math library function
calls.  Both are needed here.  The optimal compiler command is therefore
"cc -O -f68881 /usr/lib/f68881.il cos.c", which on my Sun 3/60 under SunOS
3.4 yields 3.7s of user time, which - while not as good as GCC with
inlines - is still a lot better than the above matrix.

Will this GCC inline stuff make it into a future GCC distribution?

-- 
	David L. Markowitz		Rockwell International
	...!sun!sunkist!arcturus!dav	dav@arcturus.UUCP
	The above opinions are merely that, and only mine.