GCC optimization flags for Intel Atom [closed]

Answer 1

i686 is closest. Don't go for core2.

GCC 4.1 -O3 -march=i686 GCC 4.3 -O3 -march=native

GCC 4.1 -O4 -ffast-math GCC 4.3 -O4 -ffast-math

http://macles.blogspot.com/2008/09/intel-cc-compiler-gcc-and-intel-atom.html

Answer 2

here's some cross-pollenation of blogs... what i was really hoping for was a firefox-compiled-for-atom benchmark...

Address : http :// ivoras.sharanet.org/blog/tree/2009-02-11.optimizing-for-atom.html

"As it turns out, gcc appears to do a very decent job with -mtune=native, and mtune=generic is more than acceptable. The biggest gains (in this math-heavy benchmark) come from using SSE for math, but even they are destroyed by tuning for pentium4.

"The difference between the fastest and the slowest optimization is 21%. The impact of using march instead of mtune is negligible (not enough difference to tell if it helps or not).

"(I've included k6 just for reference - I know Atom doesn't have 3dnow)

"Late update: Tuning for k8 (with SSE and O3) yields a slightly higher best score of 182."

Answer 3

There is a cool framework called Acovea (Analysis of Compiler Options via Evolutionary Algorithm), by Scott Rober Ladd, one of the GCC hackers. It's a genetic/evolutionary algorithm framework that tries to optimize GCC optimization flags for a specific piece of code via natural selection.

It works something like this: you write a little piece of benchmark code (it really has to be little, because it will be re-compiled and executed several thousand times) that represents the performance characteristics of the larger program you want to optimize. Then Acovea randomly constructs some dozens of different GCC commandlines and compiles and runs your benchmark with each of them. The best of these commandlines are then allowed to "mate" and "breed" new "children" which (hopefully) inherit the best "genes" from their "parents". This process is repeated for a couple dozen "generations", until a stable set of commandline flags emerges.