[Nauty] Squeezing out another 10%...
caj at cs.york.ac.uk
Mon Feb 14 23:25:01 EST 2005
Gordon Royle wrote:
> I have discovered through experimentation that I get an additional 10%
> performance out of geng (and hence presumably) nauty by altering the
> optimization flags from the supplied defaults... I am using a Pentium 4
> machine, and if I put
> gcc -O2 -Dmarch=pentium4
> then it is about 10% faster than
> gcc -O4
> Interestingly, it proves better to use O1/O2 with the
> architecture-specific flag than to use O3 or higher...
Just one very minor note. There is no difference at all between -O3 and
higher values, the higher values are just allowed for backwards
compatability when they used to higher.
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