Newsgroups: comp.parallel.mpi
From: rvdg@cs.utexas.edu (Robert van de Geijn)
Subject: InterCom Release R2.0.0
Organization: CS Dept, University of Texas at Austin
Date: 17 Mar 1995 22:43:17 -0600
Message-ID: <3kdod5$ij2@bigbird.cs.utexas.edu>

I thought I had posted the following message, but did not
see it on comp.parallel.mpi.  My apologies if it already appeared.

It is our pleasure to announce the second release of the
Interprocessor Collective Communications (InterCom) Library, iCC
release R2.0.0.  This library is the result of an ongoing
collaboration between David Payne (Intel SSD), `Lance Shuler (Sandia
National Laboratories), Robert van de Geijn (University of Texas at
Austin), and Jerrell Watts (California Institute of Technology),
funded by the Intel Research Council, and Intel SSD.  Other
collaborators on this project have included Mike Barnett (University
of Idaho), Satya Gupta (Intel SSD), Prasenjit Mitra (now with Oracle)
and Rik Littlefield (PNL).

The library implements a comprehensive approach to collective
communication.  The results are best summarized by the following
performance table, representative of improvements obtained on a 
16 X 32 Paragon, running under R1.2 of the O/S, with iCC R2.0.0:

                   vector        NX        InterCom      ratio
     Operation     length       (sec)       (sec)     (NX/InterCom) 
   -----------------------------------------------------------------

     Broadcast     8 bytes      0.0017      0.0014        1.21
                 64K bytes      0.0356      0.0069        5.18
                  1M bytes      0.5788      0.0493       11.75

   Global Sum      8 bytes      0.0032      0.0029        1.10
     to all      64K bytes      0.3780      0.0195       19.35 
                  1M bytes      5.9353      0.1791       33.15

Similar, or better, improvement is obtained under OSF R1.3, iCC
R2.0.0.  Attaining the improvement in performance is as easy as
linking in a library that automatically translates NX collective
communication calls to iCC calls.  Furthermore, the iCC library gives
additional functionality like scatter and gather operations, and more
general "gopf" combine operations.  

As had been planned, an MPI-like group interface to iCC is now 
available.  The interface lets the user create and free groups 
and communicators, and it gives user-defined groups complete 
access to the high performance routines in the iCC library.

We would like to note that this library is not intended to compete 
with MPI.  It was started as a research project into techniques 
required to develop high performance implementations of the MPI
collective communication calls.  We are making this library available
as a service to the user community, with the hope that these techniques
eventually are incorporated into efficient MPI implementations.

For more information, access 
 
    http://www.cs.utexas.edu/users/rvdg/intercom






