[linux-audio-dev] Re: -O3 etc

[Paul Coccoli]

On 1/12/06, Bill Schottstaedt <bil at ccrma.stanford.edu> wrote:
> I ran some timing tests, partly to check out -fast-math -- my informal impression
> is that it speeds up exp by a factor of about 2, but can slow down other things
> (FIR filters).  I didn't see any obvious improvement in -O3 over -O2.  The
> actual numbers are in the snd tarball, snd-edits.c -- look for "fast-math".
> (The table is aimed more at comparing int/float/double operations).  These
> timing numbers change by a factor of, say, 20% on each run, so don't put
> much weight on them.
>
>

I read somewhere that -Os (optimize for "smaller" code, intended for
embedded systems maybe?) sometimes produces faster code than -O2 or
-O3.  Has anybody tried that on their plugins or anything else?

Might not help at all if, as Steve Harris said, most plugin inner
loops fit in cache already.