Add cpu usage plugin (fix #4)

cpu

@@ -0,0 +1,79 @@
+#!/bin/sh
+#
+# Copyright (c) 2017 Babak Farrokhi.  All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions
+# are met:
+#
+# 1. Redistributions of source code must retain the above copyright
+#    notice, this list of conditions and the following disclaimer.
+# 2. Redistributions in binary form must reproduce the above copyright
+#    notice, this list of conditions and the following disclaimer in the
+#    documentation and/or other materials provided with the distribution.
+#
+# THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS "AS IS" AND
+# ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+# ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+# FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+# DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+# OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+# HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+# LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+# OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+# SUCH DAMAGE.
+#
+#
+#%# family=auto
+#%# capabilities=autoconf
+
+if [ "$1" = "autoconf" ]; then
+	echo yes
+fi
+
+if [ "$1" = "config" ]; then
+
+	echo 'graph_title CPU usage'
+	echo 'graph_order system interrupt user nice idle'
+	echo "graph_args --base 1000 -r --lower-limit 0 --upper-limit $PERCENT "
+	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 100'
+	echo 'system.type DERIVE'
+	echo 'system.min 0'
+	echo 'system.info CPU time spent by the kernel in system activities'
+	echo 'interrupt.label interrupt'
+	echo 'interrupt.draw STACK'
+	echo 'interrupt.max 100'
+	echo 'interrupt.type DERIVE'
+	echo 'interrupt.min 0'
+	echo 'interrupt.info CPU time spent by the kernel processing interrupts'
+	echo 'user.label user'
+	echo 'user.draw STACK'
+	echo 'user.max 100'
+	echo 'user.type DERIVE'
+	echo 'user.info CPU time spent by normal programs and daemons'
+	echo 'user.min 0'
+	echo 'nice.label nice'
+	echo 'nice.draw STACK'
+	echo 'nice.max 100'
+	echo 'nice.type DERIVE'
+	echo 'nice.info CPU time spent by nice(1)d programs'
+	echo 'nice.min 0'
+	echo 'idle.label idle'
+	echo 'idle.draw STACK'
+	echo 'idle.max 100'
+	echo 'idle.type DERIVE'
+	echo 'idle.info Idle CPU time'
+	echo 'idle.min 0'
+	exit 0
+fi
+
+iostat -c2 -w0.1 -n0 | tail -1 | awk '{ print "user.value " $3 "\nnice.value " $4 "\nsystem.value " $5 "\ninterrupt.value " $6 "\nidle.value " $7 }'
+