ARSC T3D Users' Newsletter 18, January 13, 1995

Optimization on the T3D

CRI has produced a collection of papers on optimizing on the T3D. I will e-mail any of them to T3D users who request them. Below is the README file that describes the collection:

                       CRAY T3D Optimization Techniques

                          DRAFT A (November 1994)

  The ASCII and PostScript files in this directory contain information
  on CRAY T3D optimization techniques. You can use your local print
  command (for example, lpr(1)) to print these files on your
  PostScript printer. This information is being distirbuted for Cray
  Research customer use.

  Please note that the information in these files is related to the
  current design and implementation of software on the CRAY T3D system.
  It is subject to change without notice. This may mean that a code
  change made to optimize a program in one release may prove to be
  unnecessary or even nonoptimal in a subsequent release.

  The file names and the titles of the papers correspond as follows:

  File Name       Title
  ---------       -----      Single-PE Optimization Techniques for the CRAY
                  T3D System     Programming for Performance in CRAFT on the
                  CRAY T3D System   Data Layout and Its Affect on Single-processor
                  Performance on CRAY T3D Systems
  io_opt.ascii    Input/Output (I/O) Optimization for CRAY T3D
  pvm_opt.ascii   Parallel Virtual Machine (PVM) Optimization
  shmem.ascii     Shared Memory Gets and Puts on the CRAY T3D

  We hope that these papers help you in your optimization efforts. These
  papers are our first step in an ongoing effort to provide optimization
  information. More formal information will be distributed as the
  CRAY T3D optimization methods evolve. If you have comments on these
  papers, please send them to


List of Differences Between T3D and Y-MP

The current list of differences between the T3D and the Y-MP is:
  1. Data type sizes are not the same (Newsletter #5)
  2. Uninitialized variables are different (Newsletter #6)
  3. The effect of the -a static compiler switch (Newsletter #7)
  4. There is no GETENV on the T3D (Newsletter #8)
  5. Missing routine SMACH on T3D (Newsletter #9)
  6. Different Arithmetics (Newsletter #9)
  7. Different clock granularities for gettimeofday (Newsletter #11)
I encourage users to e-mail in differences that they have found, so we all can benefit from each other's experience.
Current Editors:
Ed Kornkven ARSC HPC Specialist ph: 907-450-8669
Kate Hedstrom ARSC Oceanographic Specialist ph: 907-450-8678
Arctic Region Supercomputing Center
University of Alaska Fairbanks
PO Box 756020
Fairbanks AK 99775-6020
E-mail Subscriptions: Archives:
    Back issues of the ASCII e-mail edition of the ARSC T3D/T3E/HPC Users' Newsletter are available by request. Please contact the editors.
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