On Friday 28 November 2003 22:19, Andrew Gaffney wrote: > Vano Beridze wrote: > > Hello > > > > I have > > AMD Athlon XP 2400+, 1GB RAM > > > > I installed gentoo from stage 1 (took 1 day) with the following settings > > > > CHOST="i686-pc-linux-gnu" > > CFLAGS="-march=athlon-xp -O3" > > CXXFLAGS="-march=athlon-xp -O3" > > > > What a surprise: > > > > On the same machine with RedHat 9 (i386 packages) > > > > NetBeans 3.5.1(sun jdk 1.4.2_02) runs faster. > > > > What is the problem? Are my flags set incorrectly? > > Through the use of benchmarks, users have recently been discovering that > '-O3' can actually give you *slower* programs than '-O2'. While the code > that is generated with '-O3' is more optimized, it is also larger, which in > some/most cases, causes it not to fit into the processor cache which gives > you a large performance hit. In general, I think the best flags for you > would be '-march=athlon-xp -O2 -fomit-frame-pointer' or '-march=athlon-xp > -Os -fomit-frame-pointer' where '-Os' is the same as '-O2' but it generates > smaller binaries.
I've found with my AthlonXP that when using -Os just about everything runs much slower. Most noticably was kmail which took about 3 times as long to clean up the mail folders on exit. Pretty much everything ran sluggish though. Jason -- [EMAIL PROTECTED] mailing list
