Eliminate running processes before or after build.
With this plugin user can decide to clean the processes either before or after the build. It can either kill all processes started by the user that runs Jenkins agent (except of that process) or all child processes of Jenkins agent (note this will not affect processes running on background).
Note the plugin can decide not to perform the cleanup in case there is a chance it will affect other jobs on the same machine. In other words, it will be skipped when there is another build running on the same slave.