Gentoo Archives: gentoo-performance

From: William Kenworthy <billk@×××××××××.au>
To: gentoo-performance@l.g.o
Subject: Re: [gentoo-performance] inline considered harmful
Date: Thu, 22 Jul 2004 22:23:18
Message-Id: 1090534990.10643.10.camel@rattus.Localdomain
In Reply to: Re: [gentoo-performance] inline considered harmful by Jerry McBride
A while back I ran a large number of tests on optimisations across an
athlon t-bird 1.4g, pentium4M (dell laptop) and a cyrix 200 (for fun!). 
The applications were scientific, some home scripts and gimp
manipulations.

I was mainly interested in routines that run for many hours/days as this
was what was causing me the most grief at the time.  Basicly, ~10% gains
can be be seen between -Os (s must be for for slowest!) and -O2 (-O3 is
almost always slower than -O2)

Of course, results were highly variable, and application dependent.

I came to the conclusion that for me, compiling the system with
"-march=athlon-xp -O2 -pipe -fomit-frame-pointer -falign-functions=4"
gave the best general gain.  My next step was to be to compile all the
gui stuff with -Os to speed up startup - but I never got around to it.

Per package optimisations would be nice, but I can imagine it getting
into a far greater mess than USE flags are at the moment - getting
unusable.

BillK

On Thu, 2004-07-22 at 19:06, Jerry McBride wrote:
> On Thursday 22 July 2004 02:35 pm, Bart Alewijnse wrote: > > I'm curious as to how many of you have considered and tried using -Os
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Replies

Subject Author
Re: [gentoo-performance] inline considered harmful William Kenworthy <billk@×××××××××.au>