On Sun, 2003-03-16 at 05:32, Matthew Gatto wrote: > On Sat, Mar 15, 2003 at 03:41:53PM +0000, Dhruba Bandopadhyay wrote: > > Here is my cflag variable. > > > > CFLAGS="-march=pentium4 -O3 -pipe -fomit-frame-pointer" > > > > (1) According to the CFlags Central thread on forums and the gcc manual > > optimisations page (link [1]) the -O3 flag includes the > > -fomit-frame-pointer optimisation. Is this right? If so, why are there > > recommendations to include it in addition to -O3 (link [2&3]? > > http://freshmeat.net/articles/view/730/ > > "-O1, which turns on ... [ some flags ] ... -fomit-frame-pointer (only > on if the machine can debug without a frame pointer; otherwise, you > need to specify)" > > > [1]http://gcc.gnu.org/onlinedocs/gcc-3.2.2/gcc/Optimize-Options.html#Optimize%20Options > > [2]http://www.freehackers.org/gentoo/gccflags/flag_gcc3.html (stable) > > [3]http://www.freehackers.org/gentoo/gccflags/flag_gcc3opt.html > > (experimental) > > > > (2) How can I make my Cflag above more aggressive to give better > > performance? At the moment, it is quite basic and safe but I'm pretty > > sure more can be done with it. Anyone have a P4 and can vouch for > > additional optimisations? > > You can't optimize any more than you already are without turning on > flags which will probably only adversely effect your system. According > to the gcc man page, OPTIMIZATIONS section: > > "-O2: GCC performs nearly all supported optimizations that do not > involve a space-speed tradeoff." > > and > > "-O3 turns on all optimizations specified by -O2 and also turns on the > -finline-functions and -frename-registers options."
How about the following going by recommendations on link [3] above? CFLAGS="-march=pentium4 -O3 -pipe -fomit-frame-pointer -fforce-addr -falign-functions=4 -fprefetch-loop-arrays -funroll-loops" Many thanks. -- [EMAIL PROTECTED] mailing list
