From owner-freebsd-current  Sat Mar 18 20:51:39 2000
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Date: Sun, 19 Mar 2000 15:55:37 +1100
From: "Jacob A. Hart" <c9710216@atlas.newcastle.edu.au>
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To: Donn Miller <dmmiller@cvzoom.net>
Cc: freebsd-current@freebsd.org
Subject: Re: gcc -Os optimisation broken (RELENG_4)
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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


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