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SubjectRe: Compiling 2.2.19 with -O3 flag
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On Fri, 2002-05-24 at 07:42, Alan Cox wrote:

> Bench it and see. From my own experience -O3 made the kernel a lot larger
> and reduced overall performance - in part because the kernel already
> explicitly figures out what it wants inlined.
>
> Interestingly enough -Os outperformed -O2

Heh, now that is interesting.

Or maybe not - not too long ago I did some tests of the various
optimization options in gcc 2.96 or so and found that -O2 generates
smaller code in most cases than -Os. -Os also did not perform as good,
but I was just testing a few bits of code - nothing as versatile as the
kernel.

The end result was I recommend -O2 for both performance and size. Maybe
I should retest against the kernel...

Robert Love

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