Matthew Knepley wrote: > On Mon, Sep 21, 2009 at 2:37 PM, Anders Logg <[email protected] > <mailto:[email protected]>> wrote: > > Johan and I have set up a benchmark for parallel speedup in > > bench/fem/speedup > > Here are some preliminary results: > > Speedup | Assemble Assemble + solve > -------------------------------------- > 1 | 1 1 > 2 | 1.4351 4.0785 > 4 | 2.3763 6.9076 > 8 | 3.7458 9.4648 > 16 | 6.3143 19.369 > 32 | 7.6207 33.699 > > > These numbers are very very strange for a number of reasons: > > 1) Assemble should scale almost perfectly. Something is wrong here. > > 2) Solve should scale like a matvec, which should not be this good, > especially on a cluster with a slow network. I would expect 85% or so. >
Isn't this only for a Krylov solver? The demo uses MUMPS. Garth > 3) If any of these are dual core, then it really does not make sense since > it should be bandwidth limited. > > Matt > > > These numbers look a bit strange, especially the superlinear speedup > for assemble + solve. There might be a bug somewhere in the benchmark > code. > > Anyway, we have some preliminary results that at least show some kind > of speedup. > > It would be interesting to hear some comments on what kind of numbers > we should expect to get from Matt and others. > > The benchmark is for assembling and solving Poisson on a 64 x 64 x 64 > mesh using PETSc/MUMPS. Partitioning time is not included in the > numbers. > > -- > Anders > > -----BEGIN PGP SIGNATURE----- > Version: GnuPG v1.4.9 (GNU/Linux) > > iEYEARECAAYFAkq31d4ACgkQTuwUCDsYZdHRKgCaAlc3XbJF18kBYnZ6kYztjKyG > KFAAnRg38+SNMSAdAf5fOm3QZDTTyP97 > =DgXw > -----END PGP SIGNATURE----- > > _______________________________________________ > DOLFIN-dev mailing list > [email protected] <mailto:[email protected]> > http://www.fenics.org/mailman/listinfo/dolfin-dev > > > > > -- > What most experimenters take for granted before they begin their > experiments is infinitely more interesting than any results to which > their experiments lead. > -- Norbert Wiener > > > ------------------------------------------------------------------------ > > _______________________________________________ > DOLFIN-dev mailing list > [email protected] > http://www.fenics.org/mailman/listinfo/dolfin-dev _______________________________________________ DOLFIN-dev mailing list [email protected] http://www.fenics.org/mailman/listinfo/dolfin-dev
