On Mon, Sep 21, 2009 at 2:51 PM, Garth N. Wells <[email protected]> wrote:
> > > 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. > MUMPS should not even scale as well as a matvec. Matt > 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 >> > > > -- 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
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