Runtime options

This is the plain man page of mpcrun. You can find this exact text using mpcrun -h.

Usage

mpcrun [option] [--] binary [user args]

Main options

mpcrun provides several options for configuring the launch process. These include:

Common mpcrun options
`-N=n,--node-nb=n`	Total number of nodes (default: 1)
`-p=n, --process-nb=n`	Total number of UNIX processes (default: 1)
`-n=n, --task-nb=n`	Total number of MPC tasks (default: 1)
`-c=n, --cpu-nb=n`	Number of cpus per UNIX process (default: 1)
`--cpu-nb-mpc=n`	Number of cpus per MPC tasks
`--enable-smt`	Enable SMT capabilities (disabled by default)
`--mpmd`	Use mpmd mode (replaces binary)

You can see the hierarchy of tasks and processes in mpc runtime :

MPC task hierarchy — MPC execution model as described in this paper

Traditionally, an MPC program is launched using a combination of -N, -n and -c.

For example mpcrun -N 4 -p 8 -n 16 ./my_mpi_app launches my_mpi_app with 4 nodes, each having 2 processes, and each process running 4 tasks.

Warning

The -p option is specific to thread-based. It will have no effect if used with MPC compiled in process-mode.

Multithreading

-m=n, --multithreading=n

Define underlying threading engine

The most common modes are

pthread Use POSIX threads to ensure multithreading
ethread_mxn Use MPC own user level threading engine
ethread Use MPC own user level threading engine for debug purposes (only one thread at a time)

Network

-net=n, --net=, --network=n

Define Network mode

Using the help command, the available networks configuration should be displayed as follow

Example of available network configurations

Configured CLI switches for network configurations (default: tcpshm):

- shm:
   * tbsmmpi
   * shmmpi

- verbsshm:
   * tbsmmpi
   * shmmpi
   * verbsofirail

- verbs:
   * tbsmmpi
   * verbsofirail

Launcher

-l=n, --launcher=n

Define launcher

Using the help command, the available launchers should be displayed as follow

Example of available launchers

Available launch methods (default is srun):
   - none
   - none_mpc-gdb
   - salloc_hydra
   - srun

`--opt=<options>`	Launcher specific options
`--launchlist`	Print available launch methods
`--config=<file>`	Configuration file to load
`--profiles=<p1,p2>`	List of profiles to enable in config

Note

The --opt option is used to pass through options to the underlying launcher. It is commonly used to specify the wanted partition to slurm

mpcrun -N=2 -n=2 --opt="-p <partition>" -- ./a.out

Information

`-h, --help`	Display this help
`--show`	Display command line
`-v,-vv,-vvv`	Verbose mode (level 1 to 3)
`--verbose`	Verbose level 1
`--graphic-placement`	Output a xml file of thread placement and topology for each compute node
`--text-placement`	Output a txt file of thread placement and topology for each compute node

The verbose level are defined as such

Level 1 (v): Show basic information about the launched process
Level 2 (vv): Show logs information about the launched process
Level 3 (vvv): Show very detailed debug information about the launched process

Debugger

mpcrun provides options for configuring the debugger:

--dbg=<debugger_name>

to use a debugger

You can also launch your binaries as such if you want to keep the UNIX process outputs separate :

mpcrun -n=2 -p=2 xterm -hold -e gdb -ex r ./my_mpi_app