MPI Run Time System on SGI
- On SGI, all MPI programs are launched with the mpirun command
- mpirun -np N executable-name arguments syntax on a single host
- multi-host execution of different executables is possible
- The mpirun establishes connection with the Array Daemon with the socket interface.
- The Array Daemon launches the mpi executable.
- N+1 threads are started. One additional thread is the “lazy” thread which is blocked in mpi_init() call and terminates when all other threads call mpi_finalize()
- The mpirun -cpr (or -miser) will work on the single host to avoid the socket interface to the Array Daemon (for Checkpoint/Restart facility)
Note: start MPI programs with N < #procs
mpirun Host_A -np N a.out : Host_B -np M b.out