-If the system has the I<cpufreq-stats> kernel module loaded, this plugin reports
-the rate of p-state (cpu frequency) transitions and the percentage of time spent
-in each p-state.
+On Linux, if the system has the I<cpufreq-stats> kernel module loaded, this
+plugin reports the rate of p-state (cpu frequency) transitions and the
+percentage of time spent in each p-state.
+
+On FreeBSD it does a sysctl dev.cpu.0.freq and submits this as instance 0.
+At this time FreeBSD only has one frequency setting for all cores.
+See the BUGS section in the FreeBSD man page for cpufreq(4) for more details.
+
+On FreeBSD the plugin checks the success of sysctl dev.cpu.0.freq and
+unregisters the plugin when this fails. A message will be logged to indicate
+this.