Jason Stratos Papadopoulos wrote:
> Hey everybody. Now that our Fermat testing is starting to wind down
> I've decided to make available the source I've written for it.
Cool!
> www.glue.umd.edu/~jasonp/f24v131.zip
>
> The code there is heavily optimized for the UltraSPARC processor,
> and includes gobs and gobs of sparc assembly language. Squaring
> times are as follows:
>
> ultra-1 ultra-1 ultra-2i
> number bits 143MHz 167MHz 300MHz
>
> F22 4.2M .229 .196 .167
> F23 8.4M .465 .404 .322
> F24 16.8M 1.08 .885 .700
> F25 33.6M 1.58
>
> The GIMPS speed page places the Ultra-2i times in the neighborhood
> of a PII-300 (a Pepin test takes about the same time as an LL test
> of similar size, maybe a little less).
>
> So, a few questions:
>
> How do these times compare with MacLucasUnix on an Ultra, or with
> Prime95 for the really big sizes?
Today I posted some times - I was getting approx 0.4s per iteration for
a 256K element FFT (testing in the 4.6M range) and 0.22s for a 128K FFT
on a 200MHz Ultra.
> How fast does the program run on a really big Ultra, i.e. a 440MHz
> server with piles of RAM and a 4MB cache?
I've only got up-to-200MHz Ultras :-(
> Are there enough Ultras out there to justify making a fast LL test out
> of this code? I'd be willing to try, but only if there's sufficient
> interest; the code won't run on normal sparcs, my time is very
> limited I don't want to expend a considerable amount of
> energy on something no one will use. Would anyone like to help?
I'd be interested in helping - I think I can see the gist of what
you are doing at first glance. A whiles back I wrote a very simple
implementation of the LL test using FFTW, so I should be able to use
that as a framework. It's at
ftp://melanoma.cs.rmit.edu.au/pub/simonb/fftwll.tar.gz
if anyone's interested...
While on the subject of FFTW, I tried to use a multithreaded FFTW but
came up with the wrong results (M1279 wasn't prime :-( ). The aim of
the exercise was a fast double-checker - imagine throwing a 64 CPU Sparc
E10000 at a double checking exercise next time we want to double check
a number quickly! Has anyone used FFTW's threads?
Simon.
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