Performance notes for IRIX machines
===================================

LS-DYNA will perform best on IRIX machines if the command file sets
several environment variables.  Attached are the recommended sets of
variables for your command files for LS-DYNA jobs using either one or
multiple processors.  If you have questions about the "setenv" 
settings, contact your local SGI representative, or

   Matthew Barker
   mbar@sgi
   650-933-6576

Many of these variables are described in the "man mp" man pages.

Single Processor Jobs
---------------------
setenv MPC_GANG off
setenv OMP_DYNAMIC FALSE
setenv OMP_NUM_THREADS 1
setenv _DSM_PPM 2
setenv _DSM_PLACEMENT ROUND_ROBIN
setenv TRAP_FPE "OVERFL=ABORT; DIVZERO=ABORT; INVALID=ABORT;
INT_OVERFL=ABORT"
ls970_s_3858_sgir10k_65_p i=r.003 memory=120000000 ncpu=-1

Shared Memory Parallel Jobs
---------------------------
setenv MPC_GANG off
setenv OMP_DYNAMIC FALSE
setenv OMP_NUM_THREADS 4
setenv _DSM_PPM 2
setenv _DSM_PLACEMENT ROUND_ROBIN
setenv TRAP_FPE "OVERFL=ABORT; DIVZERO=ABORT; INVALID=ABORT;
INT_OVERFL=ABORT"
ls970_s_3858_sgir10k_65_p i=r.003 memory=120000000 ncpu=-4

Notes:
------
MPC_GANG off will help system throughput by disabling gang scheduling.

OMP_DYNAMIC FALSE will disable dynamic threads on IRIX 6.5 systems,
slightly improving performance.  This will have no effect on IRIX 
6.4 systems.

OMP_NUM_THREADS should be set to the number of processors to be 
used in the analysis.  It is important to set this even if you will
only run with a single processor.

_DSM_PPM specifies the the number of processors per memory module.
Valid values are either 1 or 2.  Setting _DSM_PPM to "2" is almost 
alway best.

_DSM_PLACEMENT ROUND_ROBIN will dramatically improve performance of
shared memory parallel jobs.

Setting the TRAP_FPE variable will stop LS-DYNA with a core dump 
when a floating point exception is encountered.  Should this occur,
contact LSTC.

For additional assistance running LS-DYNA on SGI workstation,
please contact

  Matthew Barker mbar@sgi          650-933-6576
  LSTC support   support@lstc.com  925-449-2500