Apparently, though unproven, at 10:43 on Tuesday 02 November 2010, Coert Waagmeester did opine thusly:
> Hello all, > > Possible noob question. > > I have installed a 64 bit gentoo on my intel Pentium D machine. > Now I am reading through /usr/share/portage/config/make.conf.example > > My CFLAGS on that machine is the default currently: CFLAGS="-O2 -pipe" > But according to > http://www.gentoo.org/doc/en/gentoo-amd64-faq.xml#cflags I can make it: > -O2 -march=core2 -pipe With a recent gcc (4.something) you should use -O2 -march=native -pipe Saves you having to figure out what the arch is. > Is this entirely necessary? Will it cause a big improvement? It will improve things by making all code optimized for your CPU if most of your binaries are still from the stage tarball and unoptimized for you. You will be able to measure the difference with very fancy software. You will not notice the difference. If you think you do, you are imagining it. > If I do change, how do I recompile everything? (like --newuse for USE > changes?) emerge -e world -- alan dot mckinnon at gmail dot com
