User`s guide
Running an Application [8]
This chapter contains procedures for launching your application on the Cray XMT.
8.1 Launching the Application
You use the mtarun command to launch and run a program. The mtarun command
connects to the mtarund daemon that runs on the compute node on the backend.
The daemon creates a copy of your environment and runs it on the compute nodes.
Your file directories from the login node appear on the compute nodes with the same
paths.
From the login node, you use the mtarun command to launch a program, as shown
in the following example.
mtarun MyProgram.out
The most common options to use with the mtarun command are -m max_procs
and -t min_procs.
The -m max_procs option sets the maximum number of processors for the
program. This option is the same as setting the MTA_PARAMS environment variable
to NUM_PROCS.
The -t min_procs option sets the number of processors to use when the program
starts running. By default, a program starts with one processor and adds processors,
as needed.
After launching the program, mtarun acts as the frontend of the program. mtarun
provides the following services to the program:
• Standard I/O forwarding. Provided by mtarun stdin, mtarun stdout
and mtarun stderr.
• Signal forwarding. mtarun forwards all catchable signals.
• Termination management. If the program exits normally, mtarun exits with the
same exit status. If the remote process is killed by a signal, mtarun terminates
with the matching exit status and sends a message to stderr with information
about the signal that caused the program to exit. If mtarun terminates
prematurely, the mtarun daemon uses SIGKILL to kill the program.
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