#!@@PERL@@ -w
#
# Plugin to monitor physical cpu usage in an IBM POWER P5 / OpenPower LPAR
#
# Usage: Place in /etc/munin/plugins (or make a symlink to it there)
#
# Parameters understood:
#
#       config
#       autoconf
#
# This should be run as root, so drop a file with something like this in
# /etc/munin/plugin-conf.d/lpar_cpu:
#       [lpar_cpu]
#       user root
#
# Great thanks to Nigel Griffith of IBM for the magic to get these values
#
# Author: Ingvar Hagelund <ingvar(at)linpro.no>
#
# Licence: GNU General Public Licence v2.0,
# see http://www.gnu.org/copyleft/gpl.html

use strict;

my $stats="/proc/ppc64/lparcfg";
my $cpuinfo="/proc/cpuinfo";
my $seconds=2;
my $counter="";
my $after="";
my $timebase="";

sub readstats {
	my $stats=shift;
	my $purr;

	open (STATS,"$stats") or die "Unable to read $stats, $!";
	while (<STATS>) {
		if ( /^purr\=(\d+)$/ ) { $purr = $1; }
	}
	close STATS;
	return $purr;
}

sub error {
    print "something horrible happened\n";
    exit 2;
}


################
#
# Main
#
#

if ( defined $ARGV[0] ) {

    if ( $ARGV[0] eq 'autoconf' ) {
	if ( -x $stats && -e $cpuinfo ) {
	    print "yes\n";
	    exit 0;
	}
	else {
	    print "no (I need $stats and $cpuinfo)\n";
	    exit 0;
	}
    }
    elsif ( $ARGV[0] eq 'config' ) {
	print "graph_title LPAR physical CPU usage\n";
	print "graph_vlabel percent\n";
	print "graph_category system\n";
	print "cpu.label cpu\n";
	print "cpu.type DERIVE\n";
	print "cpu.min 0\n";
	exit 0;
    }
}

$counter=readstats($stats);

open (CPUINFO,$cpuinfo) or die "Unable to read $cpuinfo, $!";
while (<CPUINFO>) {
    if (/^timebase\s+\:\s+(\d+)/) { $timebase=$1; }
}
close CPUINFO;

error() if $cpuinfo eq "";
error() if $counter eq "";
error() if $timebase eq "";

my $val=100*$counter/$timebase;
$val =~ s/(\d+)\..+/$1/;
print "cpu.value " . $val . "\n";
exit 0;