Re: [PPL-devel] GMP 4.3.0 released

Torbjorn Granlund wrote:

Roberto Bagnara bagnara@cs.unipr.it writes:

...

Speedups:

• Vastly improved assembly code for x86-64 processors from AMD and Intel.

I have run a couple of application programs based on the Parma Polyhedra Library (PPL), which heavily depends on GMP. On an AMD Opteron 2384 "Shanghai" I got the following running times (best run out of 10):

      Application A                   Application B

  GMP 4.2.4    GMP 4.3.0          GMP 4.2.4    GMP 4.3.0

    238 s        187 s              34.2 s       34.8 s

On an Intel Core2 Q9400, instead, I got:

      Application A                   Application B

  GMP 4.2.4    GMP 4.3.0          GMP 4.2.4    GMP 4.3.0

    339 s        213 s              29.8 s       28.9 s

You get less speedup than I expect to be typical (and a very slight slowdown in one case).

I am curious what GMP operations application B performs. Profile runs for both GMP versions would be helpful.

Hi Torbjorn,

I was in fact wrong. While the PPL is, generally speaking, heavily dependent on GMP, application B running time is dominated by non-GMP functions. For it, the most important GMP operation is __gmpn_popcount which consumes 12% of the running time. Thanks again,

Roberto