#!/bin/sh
#
# Plugin to monitor CPU usage.
#
# Usage: Place in /etc/munin/plugins (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=$(egrep '^cpu[0-9]+ ' /proc/stat | wc -l)
	PERCENT=$(($NCPU * 100))
	MAX=$(($NCPU * 100))
	if [ "$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.max $MAX"
	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.max $MAX"
	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.max $MAX"
	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.max $MAX"
	echo 'idle.type DERIVE'
	echo 'idle.info Idle CPU time'
	if [ "$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.max $MAX"
		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.max $MAX"
		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.max $MAX"
		echo 'softirq.type DERIVE'
		echo 'softirq.info CPU time spent handling "batched" interrupts'
		if [ "$scaleto100" = "yes" ]; then
			echo "iowait.cdef iowait,$NCPU,/"
			echo "irq.cdef irq,$NCPU,/"
			echo "softirq.cdef softirq,$NCPU,/"
		fi
	fi
	exit 0
fi

HZ=`getconf CLK_TCK`

if [ ! -z "$extinfo" ]
then
	awk -v HZ=$HZ 'BEGIN { factor=100/HZ } /^cpu / { for (i=2; i<=8; i++) { $i = int($i * factor) }; 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 -v HZ=$HZ 'BEGIN { factor=100/HZ } /^cpu / { for (i=2; i<=5; i++) { $i = int($i * factor) }; print "user.value " $2 "\nnice.value " $3 "\nsystem.value " $4 "\nidle.value " $5 }' < /proc/stat
fi