HP-MPI V2.3 for Linux Release Note

1.2.7.9 Singleton Launching
This release supports the creation of a single rank without the use of mpirun, called
singleton launching. It is only valid to launch an MPI_COMM_WORLD of size one using
this approach. The single rank created in this way is executed as if it were created with
mpirun -np 1 <executable>. HP-MPI environment variables can influence the
behavior of the rank. Interconnect selection can be controlled using the environment
variable MPI_IC_ORDER. Many command-line options that would normally be passed
to mpirun cannot be used with singletons. Examples include, but are not limited to,
-cpu_bind, -d, -prot, -ndd, -srq, and -T. Some options, such as -i, are accessible
through environment variables (MPI_INSTR) and can still be used by setting the
appropriate environment variable before creating the process.
Creating a singleton using fork() and exec() from another MPI process is subject
to the same limitations that OFED places on fork() and exec().
1.2.7.10 Using the -stdio=files Option
This option specifies that the standard input, output and error of each rank is to be
taken from the files specified by the environment variables MPI_STDIO_INFILE,
MPI_STDIO_OUTFILE and MPI_STDIO_ERRFILE. If these environment variables are
not set, /dev/null or NUL is used. In addition, these file specifications can include
the substrings %%, %h, %p, and %r, which are expanded to %, hostname, process
id, and rank number in MPI_COMM_WORLD. The files option causes the stdio options
p, r, and I to be ignored.
1.2.7.11 Using the -stdio=none Option
This option is equivalent to setting -stdio=files with MPI_STDIO_INFILE,
MPI_STDIO_OUTFILE and MPI_STDIO_ERRFILE all set to /dev/null or NUL.
1.2.7.12 Expanded Lightweight Instrumentation
This release extends HP-MPI lightweight instrumentation. Lightweight instrumentation
can be turned on by using either the -i option to mpirun or by setting the environment
variable MPI_INSTR.
HP-MPI's lightweight instrumentation is now supported when using -ha:infra and
singletons. (See “Singleton Launching” (page 21).)
Instrumentation data now includes some information on messages sent to other MPI
worlds formed via MPI_Comm_accept(), MPI_Comm_connect(), or
MPI_Comm_join(). All off-world message data is accounted together using the
designation offw regardless of which off-world rank was involved in the
communication.
HP-MPI provides an API to allow users to access the lightweight instrumentation data
on a per-process basis before the application calling MPI_Finalize(). The following
declaration in C is necessary to access this functionality:
1.2 What’s in This Version 21