#!/bin/sh
#
# Plugin to monitor CPU usage.
#
# Usage: Place in /etc/munin/node.d/ (or link it there  using ln -s)
#
# Parameters understood:
#
# 	config   (required)
# 	autoconf (optional - used by munin-config)
#
# Magic markers - optional - used by installation scripts and
# munin-config:
#
#%# family=auto
#%# capabilities=autoconf



if [ "$1" = "autoconf" ]; then
	if [ -r /proc/stat ]; then
		echo yes
		exit 0
	else
		echo no
		exit 1
	fi
fi

extinfo=""

if (`egrep '^cpu +[0-9]+ +[0-9]+ +[0-9]+ +[0-9]+ +[0-9]+ +[0-9]+ +[0-9]+' /proc/stat 2>/dev/null >/dev/null`)
then
	extinfo="iowait irq softirq"
fi

if [ "$1" = "config" ]; then

	NCPU=$(egrep '^cpu[0-9]+ ' /proc/stat | wc -l)
	PERCENT=$(($NCPU * 100))
	if [ "$scaleto100" = "yes" ]; then
		graphlimit=100
	else
		graphlimit=$PERCENT
	fi
	SYSWARNING=`expr $PERCENT '*' 30 / 100`
	SYSCRITICAL=`expr $PERCENT '*' 50 / 100`
	USRWARNING=`expr $PERCENT '*' 80 / 100`
	echo 'graph_title CPU usage'
	echo "graph_order system user nice idle" $extinfo
	echo "graph_args --base 1000 -r --lower-limit 0 --upper-limit $graphlimit"
	echo 'graph_vlabel %'
	echo 'graph_scale no'
	echo 'graph_info This graph shows how CPU time is spent.'
	echo 'graph_category system'
	echo 'graph_period second'
	echo 'system.label system'
	echo 'system.draw AREA'
	echo 'system.min 0'
	echo 'system.type DERIVE'
	echo "system.warning $SYSWARNING" 
	echo "system.critical $SYSCRITICAL" 
	echo "system.info CPU time spent by the kernel in system activities" 
	echo 'user.label user'
	echo 'user.draw STACK'
	echo 'user.min 0'
	echo "user.warning $USRWARNING"
	echo 'user.type DERIVE'
	echo 'user.info CPU time spent by normal programs and daemons'
	echo 'nice.label nice'
	echo 'nice.draw STACK'
	echo 'nice.min 0'
	echo 'nice.type DERIVE'
	echo 'nice.info CPU time spent by nice(1)d programs'
	echo 'idle.label idle'
	echo 'idle.draw STACK'
	echo 'idle.min 0'
	echo 'idle.type DERIVE'
	echo 'idle.info Idle CPU time'
	if [ "$scaleto100" = "yes" ]; then
		echo "system.cdef system,$NCPU,/"
		echo "user.cdef user,$NCPU,/"
		echo "nice.cdef nice,$NCPU,/"
		echo "idle.cdef idle,$NCPU,/"
	fi
	if [ ! -z "$extinfo" ]
	then
		echo 'iowait.label iowait'
		echo 'iowait.draw STACK'
		echo 'iowait.min 0'
		echo 'iowait.type DERIVE'
		echo 'iowait.info CPU time spent waiting for I/O operations to finish'
		echo 'irq.label irq'
		echo 'irq.draw STACK'
		echo 'irq.min 0'
		echo 'irq.type DERIVE'
		echo 'irq.info CPU time spent handling interrupts'
		echo 'softirq.label softirq'
		echo 'softirq.draw STACK'
		echo 'softirq.min 0'
		echo 'softirq.type DERIVE'
		echo 'softirq.info CPU time spent handling "batched" interrupts'
		if [ "$scaleto100" = "yes" ]; then
			echo "iowait.cdef iowait,$NCPU,/"
			echo "irq.cdef irq,$NCPU,/"
			echo "softirq.cdef softirq,$NCPU,/"
		fi
	fi
	exit 0
fi


if [ ! -z "$extinfo" ]
then
	awk '/^cpu / { print "user.value " $2 "\nnice.value " $3 "\nsystem.value " $4 "\nidle.value " $5 "\niowait.value " $6 "\nirq.value " $7 "\nsoftirq.value " $8 }' < /proc/stat
else
	awk '/^cpu / { print "user.value " $2 "\nnice.value " $3 "\nsystem.value " $4 "\nidle.value " $5 }' < /proc/stat
fi