Reliable Multicasts for Beowulfs: Software

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This software allows faster computations on Beowulf and similar clusters by using point-to-multipoint communications to broadcast information between nodes. See the project description.

Version 0.94, December 2002

Conceptual changes of consequence include:

Recovery at the UDP datagram level instead of MPI message level. Much better performance for messages >> 32 KB.
Channel state eliminated; simpler shutdown sequence
Resend over EFAULT

Usage

Include "mpim.h"
Call MPIM_Init() instead of (or after) MPI_Init() and before first broadcast. Fortran note 2001nov21: you must call MPI_Init() from Fortran before calling MPIM_Init(); C users can optionally skip MPI_Init()
Call MPIM_Finalize() instead of MPI_Finalize() (eliminates alarm interaction with MPI shutdown).
Then replace your call(s) to MPI_Bcast() with call(s) to MPIM_Bcast() with exactly the same arguments. Fortran interfaces for all three calls are included.

Notes

This version tested only under RedHat Linux 6.2-7.2 on Intel and Alpha. Previous versions have been tested with Sparc Solaris 7. Access to larger clusters for testing or your results are desired.
Use with mpich; versions 1.2.1-1.2.4 used for testing and development.

Version 0.94

Version 0.94: mpim-2002dec16.tgz: latest version; complete; less thoroughly tested
nack.c : multicast and TCP ACK functions. Nominally independent of MPICH
mpim.c/.h : glue to MPICH: MPIM_Init(), MPIM_Finalize(), MPIM_Bcast()
mpimtest.c : simple example program sends an integer nloop times using MPI_Bcast() or MPIM_Bcast().
mpimf.c : fortran interfaces to C functions; compile with -DDOUBLE for function names with __ appended
channel.c/.h : a convenience structure and fns to manipulate it; basically a socket
comm.c/.h : ditto; a comm is a set of channels.
ring.c/.h : ring buffers management

Peter Tamblyn / ptamblyn@astro101.com

Last modified: December 16, 2002