|Bill Allombert on Fri, 07 Nov 2003 13:01:29 +0100|
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|Re: Experimenting with the Alpha build.|
On Thu, Nov 06, 2003 at 12:25:32PM -0800, Phil Carmody wrote: > --- Karim BELABAS <Karim.Belabas@math.u-psud.fr> wrote: > I also recompiled GMP with -ffast-math too for the test. In theory GMP might > perform some FP maths (FFT multiplication? or is it NTT?). I wasn't expecting > massive changes, I just fancied experimenting. I don't thing GMP use FP on the alpha. FFT is implemented using modular arithmetic. Also the bench never try to multiply large numbers so FFT is not used. > The only ones that had an improvement more than the > likely noise floor were: > > * Testing analyz for gp-sta..TIME=445 for gp-dyn..TIME=399 > * Testing number for gp-sta..TIME=226 for gp-dyn..TIME=231 > > vs. the "slow" old > > * Testing analyz for gp-sta..TIME=463 for gp-dyn..TIME=411 > * Testing number for gp-sta..TIME=242 for gp-dyn..TIME=243 > > analyz is a bit weird - I was expecting -dyn to by slower than -sta > across the board. If you have a lot of cache, that is not unexpected: dynamic linking resolve functions only when they are referenced and analyz use very few functions. The current bench basically run every GP functions on nearly trivial input. For tuning purpose, we need to write a special benchmark that give a more accurate view of PARI performance on the platform. Anyone interested in doing this ? Bill.