-O3 vs. -O2 (was Re: [ale] sharing an experience....debian....)

[danscox at mindspring.com (Danny Cox)]

Jeff,

On Wed, 2004-02-11 at 22:44, Jeff Hubbs wrote:
> There's another reason why I ask.  I frequently install Gentoo on slow
> machines because a) I want to wring every last bit of performance I can
> out of the hardware available and b) I'm not under time pressure to do
> so :)
> 
> But, according to this, in doing so and accepting the -O3 optimization
> suggested, I may only be hurting myself, ESPECIALLY if after building
> gcc, glibc, etc. in the bootstrap phase with -O3 and subsequently
> compiling everything else with that gcc, it might be taking m hours
> (days?) longer than necessary.

	You might also see '-Os', which optimizes for size.  Smaller usually
runs faster as well.  I've seen some of the embedded kernel developers
suggest this when building the kernel for their systems....

	Just more for you to ponder ;-).

-- 
kernel, n.: A part of an operating system that preserves the
medieval traditions of sorcery and black art.

Danny