On Fri, 26 Sep 2003, Rick Johnson wrote:
One question I've always had is why Red Hat still compiles for
i386
(march=i386 mcpu=i686 - ok, so they get i686 instruction ordering)? Once
upon a time, I rebuilt my entire RH 7.3 tree and a good portion of my RH
8.0 tree for i686 and/or athlon. I've also run Gentoo, compiled for
Athlon XP, which isn't as solid of a comparison, but is still a "Linux"
general comparison. In both Red Hat cases, there was an appreciable
difference, especially in X GUI "redraw" speed and application start
times.
The general consensus has been that this is the placebo effect in action.
Especially given the fact that glibc already has an i686 variant, and that
objective, precise benchmarks are in short supply, it might be valuable to
first answer the question of what performance changes different compiler
options really provide.
-- Elliot
Individualists, unite!