Sugiro usar o plug-in cpubyprocess .
Uso:
# Plugin to monitor CPU usage, for a selected set of processes. Tested on FreeBSD.
#
# Author: Erik Cederstrand
# Based on http://waste.mandragor.org/munin_tutorial/cpubyuser
# Thanks to Yann Hamon.
#
# Usage: Place in /usr/local/etc/munin/plugins/ (or link it there using ln -s)
# Add this to your /ur/local/etc/munin/plugin-conf.d/plugins.conf:
# [cpubyproc]
# env.procs httpd java