On Sun, Jan 16, 2005 at 10:40:12AM -0500, Steve Snyder wrote:
> Is there a benchmark or set of benchmarks that would allow me to test the
> suitability of the CONFIG_CC_OPTIMIZE_FOR_SIZE kernel config option?
>
> It seems to me that the benefit of this option is very dependant on the
> amount of CPU cache installed, with the compiler code generation being a
> secondary factor. The use, or not, of CONFIG_CC_OPTIMIZE_FOR_SIZE is
> basically an act of faith without knowing how it impacts my particular
> environment.
>
> I've got a Pentium4 CPU with 512KB of L2 cache, and I'm using GCC v3.3.3.
> How can I determine whether or not CONFIG_CC_OPTIMIZE_FOR_SIZE should be
> used for my system?
>
> Thanks.
In theory, -O2 should produce faster code.
In practice, I don't know about any recent benchmarks comparing -Os/-O2
kernels.
In practice, I doubt it would make any noticable difference if the
kernel might be faster by let's say 1% with one option compared to the
other one.
The main disadvantage of -Os is that it's much less tested for kernel
compilations, and therefore miscompilations are slightly more likely.
cu
Adrian
--
"Is there not promise of rain?" Ling Tan asked suddenly out
of the darkness. There had been need of rain for many days.
"Only a promise," Lao Er said.
Pearl S. Buck - Dragon Seed
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