Date: Sun, 19 Mar 2000 15:55:37 +1100 From: "Jacob A. Hart" <c9710216@atlas.newcastle.edu.au> To: Donn Miller <dmmiller@cvzoom.net> Cc: freebsd-current@freebsd.org Subject: Re: gcc -Os optimisation broken (RELENG_4) Message-ID: <38D45DC9.70B9ABB3@atlas.newcastle.edu.au>
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Donn Miller wrote: > > It's probably more of a "placebo effect", which makes you think your > are getting a big boost in performance. I'll admit that I've never > seen a whole order or magnitude increase in performance between -O and > -mpentium-O3, or whatever - it probably gives you boosts here and > there. Optimization is pretty good, as I've found out, with > plain-jane -O. Beyond that, I think your performance gains are > minimal. > > And yes, I think it's really macho to be usin' hopped-up CFLAGS, like > -march=pentium -Os -pipe. I feel really studly doing this. :-) Damn straight! But you ain't seen nothing yet... > We should do a survey, and find out what the guys use for CFLAGS and > COPTFLAGS and compare them to what the female users are using. That > would be interesting. Let's get the ball rolling then, shall we? CFLAGS/COPTFLAGS for day-to-day compiles (kernel, X, world, etc.): -O3 -march=pentiumpro -malign-double -fomit-frame-pointer -funroll-loops -fstrict-aliasing -pipe CFLAGS when I *REALLY* feel the need for speed (lame, mpg123, xmame, etc.): -O3 -march=pentiumpro -malign-double -malign-loops=4 -malign-jumps=4 -malign-functions=4 -fomit-frame-pointer -ffast-math -funroll-loops -fstrict-aliasing -pipe -O2 used to be my switch of choice so the -funroll-loops flag in the above strings may be redundant (can't remember). Considering, though, that the length of one's CFLAGS variable is directly proportional to studliness, I have little choice but to leave it there ;-) Can't say that I care for football, though. > - Donn -jake c9710216@atlas.newcastle.edu.au To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-current" in the body of the message
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