Did you look at the release notes and documentation about the ib RPI
module? Check out the LAM/MPI User's Guide. There's some important
information in there about the limitations of the ib RPI and its
tweakable run-time parameters that can dramatically help performance.
(short version: we only implemented basic ib functionality; we stopped
working on the ib RPI when we started working on Open MPI, about 18
months ago)
On Jun 16, 2005, at 10:11 AM, Galen Arnold wrote:
> Is anybody else trying out new lam builds [nightly snapshots] with
> infiniband?
>
> I'm seeing sharp scaling performance drops in bandwidth as I scale
> from 8x2 -> 16x2 [couple hundred MB/s drops to 10s of MB/s].
> mpich2-1.0.1 doesn't have this issue and performs well out to at least
> 64x2.
>
> If anybody's got hints on ways to get better performance from:
>
> setenv LAM_MPI_SSI_rpi ib
>
> ...I'd like to hear them.
>
> -Galen
> --
> Galen Arnold, consulting group system engineer
> National Center for Supercomputing Applications
> 605 E. Springfield Avenue (217) 244-3473
> Champaign, IL 61820
> arnoldg_at_[hidden]
> <arnoldg.vcf>_______________________________________________
> This list is archived at http://www.lam-mpi.org/MailArchives/lam/
--
{+} Jeff Squyres
{+} jsquyres_at_[hidden]
{+} http://www.lam-mpi.org/
|
