Stroller <[EMAIL PROTECTED]> writes: > On 29 Sep 2003, at 12:10 pm, Ulrich Rhein wrote:
>> gcc doesn't use SIMD instructions (except in very rare cases), because >> it is hard for a compiler to use them. Additionally, gcc doesn't >> generate much faster (just bigger) code when compiling with -march=..., >> if it does generate different code at all. There is usually no >> significiant performance gain with it. > Why is Gentoo's ability to set CFLAGS optimisations in make.conf so > widely touted, then..? IMHO, people seem to have a strong belief in optimizing compilers in general and that adoptions to a higher CPU type have great results. Even the simple fact that gcc offers -march=-flags makes you think that they have a noticeable effect. Additionally, if you have a distro that is 'perfectly adapted to your system', you have something more individual... It's more based on psychology than on facts. > Surely if what you say is true, then this is a redundant feature of > portage. Not really, though. CFLAGS is only one part of the possible tweaks; for instance you can simply try to link parts of the system statically against the dietlibc instead of the glibc, which really does have *massive* improvements: Statically linked supervise (in daemontools) with 22k memory footprint. An *empty* process dynamically linked to the glibc uses over 200k. Uli -- "Or have we eaten on the insane root, that takes the reason prisoner?" -- MacBeth I, 3 -- [EMAIL PROTECTED] mailing list
