When using the ch_p4 device, a number of command-line arguments may be used to control the behavior of the program.
If your configuration of mpich used -device=ch_p4, then some of the
p4 debugging capabilities are available to you. The most useful of
these are the command line arguments to the application program. Thus
mpirun -np 10 myprog -p4dbg 20 -p4rdbg 20results in program tracing information at a level of 20 being written to stdout during execution. For more information about what is printed at what levels, see the p4 Users' Guide [1].
If one specifies -p4norem on the command line, mpirun will not
actually
start the processes. The master process prints a message suggesting how the
user can do it. The point of this option is to enable the user to start the
remote processes under his favorite debugger, for instance. The option only
makes sense when processes are being started remotely, such as on a
workstation network. Note that this is an argument to the program, not
to mpirun. For example, to run myprog this way, use
mpirun -np 4 myprog -p4norem
By default, the working directory for processes running remotely with ch_p4 device is the same as that of the executable. To specify the working directly, use -p4wdir as follows:
mpirun -np 4 myprog -p4wdir myrundir