Scroll to navigation

HWLOC-PS(1) hwloc HWLOC-PS(1)


hwloc-ps - List currently-running processes or threads that are bound


hwloc-ps [options]


List all processes, even those that are not bound to any specific part of the machine.
Only show process of PID <pid>, even if it is not bound to any specific part of the machine.
Only show processes whose name contains <name>, even if they are not bound to any specific part of the machine. This is not supported on all operating systems.
Only show processes of the user whose UID is <uid>, or processes of all users if all is given. By default, only processes of the current user are displayed. This is currently only supported on Linux.
Report OS/physical indexes instead of logical indexes
Report logical indexes instead of physical/OS indexes (default)
Show process bindings as cpusets instead of objects.
Show threads inside processes. If -a is given as well, list all threads within each process. Otherwise, show all threads inside each process where at least one thread is bound. This is currently only supported on Linux.
Report the last processors where the process/thread ran. Note that the result may already be outdated when reported since the operating system may move the tasks to other processors at any time according to the binding.
Include objects disallowed by administrative limitations.
Append the output of the given command to each PID line. For each displayed process ID, execute the command <cmd> <pid> and append the first line of its output to the regular hwloc-ps line.
Run the tool as a JSON server that waits for other process' requests on a port and sends back binding information. See contrib/hwloc-ps.www/ for details.
Use the given port number instead of the default 8888.
Increase verbosity of the JSON server.
Display help message and exit.


By default, hwloc-ps lists only those currently-running processes that are bound. If -t is given, processes that are not bound but contain at least one bound thread are also displayed, as well as all their threads.

hwloc-ps displays process identifier, command-line and binding. The binding may be reported as objects or cpusets.

By default, process bindings are restricted to the currently available topology. If some processes are bound to processors that are not available to the current process, they are ignored unless --disallowed is given.

The output is a plain list. If you wish to annotate the hierarchical topology with processes so as to see how they are actual distributed on the machine, you might want to use lstopo --ps instead (which also only shows processes that are bound).

The -a switch can be used to show all processes, if desired.


If a process is bound, it appears in the default output:

$ hwloc-ps
4759 Core:0 myprogram

If a process is not bound but 3 of his 4 threads are bound, it only appears in the thread-aware output (or if explicitly selected):

$ hwloc-ps

$ hwloc-ps -t
4759 Machine:0 myprogram
4759 Machine:0
4761 PU:0
4762 PU:2
4765 PU:1

$ hwloc-ps --pid 4759
4759 Machine:0 myprogram

To display the binding of already running MPI processes (launched by Open MPI) and append their MPI rank (in MPI_COMM_WORLD) to each line:

$ hwloc-ps --pid-cmd myscript
29093 L1dCache:0 myprogram OMPI_COMM_WORLD_RANK=0
29094 L1dCache:2 myprogram OMPI_COMM_WORLD_RANK=1
29095 L1dCache:1 myprogram OMPI_COMM_WORLD_RANK=2
29096 L1dCache:3 myprogram OMPI_COMM_WORLD_RANK=3

where myscript is a bash script doing:

cat /proc/$1/environ 2>/dev/null | xargs --null --max-args=1 echo | grep OMPI_COMM_WORLD_RANK


hwloc(7), lstopo(1), hwloc-calc(1), hwloc-distrib(1), and hwloc-ps.www/README

February 11, 2021 2.4.1