Re: [ACPI] ACPI mentioned on lwn.net/kernel

[Linus Torvalds]

On Sat, 26 Jan 2002, Martin Eriksson wrote:
>
> Hmm.. I tried to compile the kernel with -Os (gcc 2.96-98) and I just got a
> ~1% smaller vmlinux and a ~3% smaller bzImage.

Note that while "-Os" exists and is documented, as far as I know gcc
doesn't actually do much with it. It really acts mostly as a "disable
certain optimizations" than anything else.

In the 3.0.x tree, it seems to change some of the weights of some
instructions, and it might make more of a difference there. But at the
same time it is quite telling that "-Os" doesn't even change any of the
alignments etc - because gcc developers do not seem to really support it
as a real option. It's an after-thought, not a big performance push.

		Linus