List Archive: gentoo-performance
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On Monday 22 November 2004 08:47, Matthew Groote-Kirsch wrote:
> I settled on:
> CFLAGS="-O2 -frename-registers -ftracer -funroll-loops
> -fomit-frame-pointer -pipe -march=athlon"
> Looking around on the forums a bit, it seemed like -O2 is recommended
> over -O3.
Aditionally there have been times when -O2 has been shown to be faster
than -O3. Similarly, the -funroll-loops might actually create slower code
due to more cache misses. Modern processors are complex systems where
nondeterministic parts like the cache can have a significant impact on
performance. The only real way to determine what is fastest would be to
run real-world (not simple loops) tests (with timing) for each option
Paul de Vrieze