Re: Pari Slowdown?

[Bill Allombert <Bill.Allombert@math.u-bordeaux1.fr>]

On Sun, Jun 28, 2009 at 01:02:57AM +0100, Jason Moxham wrote:
> Hi
> 
> Doing some very rough benchmarks of Pari on 64bit linux with GMP
> pari-2.4.2-alpha
> ? gettime() ; isprime(2^127-1,2);gettime()
> %3 = 4
> ? gettime() ; isprime(2^521-1,2);gettime()
> %4 = 332
> ? gettime() ; isprime(2^607-1,2);gettime()
> %5 = 857
> ? gettime() ; isprime(2^1279-1,2);gettime()
> %6 = 9845
> 
> pari-svn
> ? gettime() ; isprime(2^127-1,2) ; gettime()
> %1 = 8
> ? gettime() ; isprime(2^521-1,2) ; gettime()
> %2 = 420
> ? gettime() ; isprime(2^607-1,2) ; gettime()
> %3 = 1108
> ? gettime() ; isprime(2^1279-1,2) ; gettime()
> %4 = 12885
> 
> 
> This is all on the same machine with gcc-4.2.2,MPIR-1.2.1, nehalem 2.6Ghz
> 
> I tried make tune , but it didn't make any significant difference.

Thanks, this is a slowdown caused by this change:

  BA 35- direct implementation of ZX_mul, ZX_sqr using Kronecker's trick + mul

We really need to tune ZX_mul and ZX_sqr.

Cheers,
Bill.