Padb is a Job Inspection Tool for examining and debugging parallel programs, primarily it simplifies the process of gathering stack traces on compute clusters however it also supports a wide range of other functions. Padb supports a number of parallel environments and it works out-of-the-box on the majority of clusters. It's an open source, non-interactive, command line, script-able tool intended for use by programmers and system administrators alike.

Padb is developed and maintained by Ashley Pittman.

Recent News

  • 08-12-10: 3.3 release avaliable for download. It is recommended all users upgrade to version 3.3.
  • 23-10-10: 3.2-beta1 avaliable for download.
  • 06-10-09: 3.0 release avaliable for download.
  • 15-09-09: 3.0-rc2 avaliable for download.
  • 01-09-09: A 3.0-rc release is avaliable to download from the downloads page.
  • 25-06-09: A 2.5 stable release (version 2.5) is avaliable to download from the downloads page.


The following modes of operation are supported:

What padb can't do

Padb is a job inspection tool, it can tell you want you want to know about your job and your MPI stack, it will not, however, tell you about your cluster as a whole and it won't diagnose problems with your wider environment, including you job launcher or runtime environment. Padb does not launch or wrap your jobs for you, it is not a job harness but rather attaches to or targets jobs which are already running.


padb is licensed under the LGPL and as such is open-source and free to use and modify.


Padb was originally conceived by software developers at Quadrics around 2004 to solve the kind of problems facing them at the time. It's been a part of the Quadrics software stack for a number of years and has recently been made available to a wider audience. It has been commercially supported for a number of years and is known to work at a scale of tens of thousands of processes.

Parallel Environments

Padb works and is supported on the following parallel environments and MPI stacks. Not all features are available on all runtimes.

In addition padb can be told to target individual UNIX processes.


Padb requires very little support from the OS or parallel environment to run, it's main use is to assist in the debugging of parallel applications, it's therefore assumed that you have a working MPI stack or other parallel environment and that "Hello world" application runs to completion without error.
A Linux operating system is assumed and a working gdb is required for stack trace functionality. Work on a solaris port is under way.