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Date: Sat, 26 Jan 2002 13:42:52 -0800 (PST)
From: Linus Torvalds <torvalds@transmeta.com>
To: Martin Eriksson <nitrax@giron.wox.org>
cc: Jamie Lokier <lk@tantalophile.demon.co.uk>, <linux-kernel@vger.kernel.org>
Subject: Re: [ACPI] ACPI mentioned on lwn.net/kernel
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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

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