User`s guide

22 Cray T3E User’s Guide

Micro-

processor

Local

Memory

Support

Circuitry

Network

Router

-Z +Z

-Y-X

Figure 3.1: The components of Cray T3E node.

This is a problem only if you are using the SHMEM library for commu-

nication. The MPI library, for example, handles the streams mechanism

properly.

The streams mechanism can be disabled or enabled on the user level by

using the environment variable $SCACHE_D_STREAMS. To enable streams,

give the command

setenv SCACHE_D_STREAMS 1

before executing your program. To disable streams, set the environment

variable to 0. Use the command udbsee to see whether you have rights

to use the streams mechanism.

You can also set the streams using the C/C++ function

#include <mpp/rastream.h>

void set_d_stream(int ss);

or the Fortran routine

INTEGER :: ss

CALL SET_D_STREAM(ss)

See the manual pages for more details (man intro_streams).