#!/usr/bin/perl
#
# Copyright 2012 Chris Wilson
# Copyright 2006 Holger Levsen
#
# This plugin monitors ALL processes on a system. No exceptions. It can
# produce very big graphs! But if you want to know which processes are
# killing your system by page faulting, without knowing what to monitor
# in advance, this can help; or in addition to one of the more specific
# plugins to monitor just Apache or MySQL, for example.
#
# Each counter is a DERIVE (difference since the last counter reading)
# of the number of major page faults, usually 4k each, read in by a
# process. Memory mapped files probably contribute to this. The process
# cannot continue until the page fault is served, so this is a
# high-priority read that usually indicates memory starvation.
# Processes with no page faults at all are ignored. Processes
# that die may not appear on the graph, and anyway their last chunk of
# CPU usage before they died is lost. You could modify this plugin to
# read SAR/psacct records if you care about that.
#
# This program is free software; you can redistribute it and/or
# modify it under the terms of the GNU General Public License
# as published by the Free Software Foundation; version 2 dated June,
# 1991.

#scriptname=`basename $0`
#vsname=`echo $scriptname | perl -ne '/^vserver_proc_VM_(.*)/ and print $1'`

#if [ "$1" = "suggest" ]; then
#	ls -1 /etc/vservers
#	exit 0
#elif [ -z "$vsname" ]; then
#	echo "Must be used with a vserver name; try '$0 suggest'" >&2
#	exit 2
#fi

use strict;
use warnings;

my $cmd = "ps -eo maj_flt,comm h";
open PS, "$cmd|" or die "Failed to run ps command: $cmd: $!";

# my $header_line = <PS>;
my %total_by_process;

while (<PS>)
{
	my @fields = split;
	my $value = $fields[0];
	my $process = $fields[1];

	# remove any / and everything after it from the process name,
	# e.g. kworker/0:2 -> kworker
	$process =~ s|/.*||;

	# remove any . at the end of the name (why does this appear?)
	# $process =~ s|\.$||;

	# change any symbol that's not allowed in a munin variable name to _
	$process =~ tr|a-zA-Z0-9|_|c;

	$total_by_process{$process} += $value;
}

foreach my $process (keys %total_by_process)
{
	# remove all processes with 0 faults
	if (not $total_by_process{$process})
	{
		delete $total_by_process{$process};
	}
}

close(PS);

if (@ARGV and $ARGV[0] eq "config")
{
	print <<END;
graph_title Page faults by Process
graph_args --base 1000
graph_vlabel major page faults
graph_category processes
graph_info Shows number of major page faults caused by each process name
END

	my $stack = 0;
	sub draw() { return $stack++ ? "STACK" : "AREA" }
	print map
	{
		"$_.label $_\n" .
		"$_.min 0\n" .
		"$_.type DERIVE\n" .
		"$_.draw " . draw() . "\n"
	} sort keys %total_by_process;
}
else
{
	print map
	{
		"$_.value $total_by_process{$_}\n"
	} sort keys %total_by_process;
}

exit(0);