[Openmcl-devel] Bignum speed

Waldek Hebisch hebisch at math.uni.wroc.pl
Sun Oct 19 14:41:56 PDT 2008

R. Matthew Emerson wrote:
> On Oct 17, 2008, at 1:22 AM, R. Matthew Emerson wrote:
> >
> > On my machine, I get 2.450994 seconds on the x86-64 lisp, and on the
> > experimental x86-32 lisp, I get 0.344 seconds.  (Just for grins, I can
> > report that an old PowerBook G4 gets 0.909 seconds.)  So, yes,  the
> > x86-64 lisp looks pretty bad.
> [...]
> >
> > Anyway, that's just additional evidence to support gb's prior message
> > that there's plenty of room for some straightforward tuning.  If
> > tuning the lisp code doesn't provide good enough results, it might not
> > be too hard to adapt the x8632 assembly code for x8664.  Maybe if I
> > get some free time...
> This bugged me enough that I went ahead and improved the x8664 bignum  
> multiply performance by replacing the inner loop of the multiply- 
> bignums routine with a lap function that I adapted from the x8632  
> version.
> This improves performance on that mini-benchmark to 0.33 seconds,  
> basically at parity with the experimental 32-bit lisp.  Not  
> outstanding, but at least we won't be laughed at by all the other kids.

Thanks, on my machine the benchmark now takes 0.284s.  I also
see nice improvement on real-life problems.

                              Waldek Hebisch
hebisch at math.uni.wroc.pl 

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