#!/usr/bin/perl -w
#
# munin plugin for monitoring cpu frequency
# Since multiple cpus on one graph doesn't really work, this plugin links to a cpu, i.e. cpufreq_cpu0
# 
# written by BenV / JuNe
# email: benv-munin@junerules.com
#
# Version: 0.1
#
# Requires:
#   Storable         (saving state)
#
# Parameters:
#
#	config		required
#
# Configurable variables
#   statedir    	location where the state file is saved. Defaults to /var/lib/munin/plugin-state.
#   statefile    	name that's appended to statedir as filename for saving state. Defaults to "cpufreq_$cpu.state"
#
#%# family=auto
#%# capabilities=autoconf suggest

use strict;

if ($ARGV[0] and $ARGV[0] eq "autoconf" ) {
	# Check required perl modules
	unless (eval "require Storable")
	{
		print "No (Missing Storable)\n";
		exit 1;
	}
	# Check for required proc/sys files
	if (-d "/sys/devices/system/cpu/cpu0/cpufreq")
	{
		print "Yes\n";
		exit 0;
	}
	print "No (Couldn't find /sys/devices/system/cpu/cpu0/cpufreq dir)";
	exit 1;
}

if ($ARGV[0] and $ARGV[0] eq 'suggest' ) {
	foreach my $d (</sys/devices/system/cpu/cpu[0-9]*/cpufreq/>)
	{
		$d =~ /(cpu[0-9]+)/i;
		print "$1\n";
	}
	exit 0;
}

if (eval "require Storable")
{
	Storable->import(qw /lock_store lock_nstore lock_retrieve/);
}
else
{
	die "Sorry, you don't have Storable. (update your perl!)\n";
}

# Let's see what is requested.
my $target;
if ($0 =~ /_(cpu\d+)$/i)
{
	$target = $1;
}
else
{
	die "Error: we need to know what cpu you want, so link this plugin as cpufreq_cpu0 orso.";
}

my $statedir	= $ENV{"statedir"} || "/var/lib/munin/plugin-state/";
my $statefile = $statedir.($ENV{"statefile"} || "/cpufreq_$target.state");
$statefile = glob($statefile); # Make it saner, remove tildes. Not foolproof though ;)

my $cpufreq;

eval { $cpufreq = lock_retrieve($statefile); };
unless(defined($cpufreq))
{
	print STDERR "Couldn't read state file! (ignore this error on first run)\n";
	$cpufreq = {};
}

my $cpufreq_now = {};
foreach my $d (</sys/devices/system/cpu/$target/cpufreq/stats/>)
{
	unless(open(TIS, "<", "$d"."/time_in_state"))
	{
		die "Could not open ${d}/time_in_state: $!\n";
	}
	$d =~ /(cpu[0-9]+)/i;
	my $cpu = $1;
	while(<TIS>)
	{
		if (/^(\d+)\s(\d+)/)
		{
			$cpufreq_now->{$cpu}{$1} = $2;
			$cpufreq_now->{total}{$cpu} = 0 unless(defined($cpufreq_now->{$cpu}));
			$cpufreq_now->{total}{$cpu} += $2;
		}
	}
	close(TIS);
}

# Let's figure out the percentages.
my %freq_p;
my $cpu = $target;
foreach my $freq (keys %{$cpufreq_now->{$cpu}})
{
	my $new = $cpufreq_now->{$cpu}{$freq};
	my $old = (defined($cpufreq->{$cpu}{$freq})?$cpufreq->{$cpu}{$freq}:0); # If no old data, we average everything.
	my $total = $cpufreq_now->{total}{$cpu};
	$total -= $cpufreq->{total}{$cpu} if (defined($cpufreq->{total}{$cpu}));
	if (defined($total) && $total > 0)
	{
		my $p = ($new - $old) / $total;
		$freq_p{$cpu}{$freq} = $p * 100.0;
		$freq_p{avg}{$cpu} += $p * $freq; # Average speed, weighted average
	}
	else
	{
		$freq_p{$cpu}{$freq} = 0;
	}
}

if ( $ARGV[0] and $ARGV[0] eq "config" ) 
{
	print "graph_title Cpu frequency usage of $target\n";
	print "graph_args --base 1000 -l 0\n";
	print "graph_vlabel CPU Frequency %\n";
	print "graph_category System\n";
	print "graph_info This graph shows information about the cpu frequency scaling of your CPU(s)\n";

	my $count = 0;
	my ($r,$g,$blue) = (0,255,0);
	my $range = scalar(keys(%{$freq_p{$cpu}}));
	my $step = (255+255) / ($range - 1);
	# In order to let color work, let's go from green to yellow to red -- 00FF00 to FFFF00 to FF0000. 256 and 256 steps.
	foreach my $freq (sort { $a <=> $b } keys %{$freq_p{$cpu}})
	{
		printf "freq_%d.label %s\n", $freq, "$freq KHz";
		printf "freq_%d.info %s\n", $freq, "Time $cpu spent (percentage) running on $freq KHz";
		printf "freq_%d.type GAUGE\n", $freq;
		printf "freq_%d.draw %s\n", $freq, ($count++?"STACK":"AREA");
		printf "freq_%d.colour %02X%02X%02X\n", $freq, $r,$g,$blue;
		# Update color
		my $s = $step;
		if ($r < 255)
		{
			$r += $s;
			if ($r > 255)
			{
				$s = $r - 255;
				$r = 255;
				$g -= $s;
			}
		}
		else
		{
			$g -= $step;
			$g = 0 if ($g < 0);
		}
	}
	printf "cpuspeed_avg.label %s\n", "Average speed of cpu $cpu";
	printf "cpuspeed_avg.info %s\n", "Average speed of cpu $cpu scaled to a percentage";
	printf "cpuspeed_avg.GAUGE\n";
	printf "cpuspeed_avg.LINE2\n";
	printf "cpuspeed_avg.colour 0000FF\n";
	exit 0;
}

# Print requested garbage.
foreach my $freq (sort { $a <=> $b } keys %{$freq_p{$cpu}})
{
	printf "freq_%d.value %s\n", $freq, $freq_p{$cpu}{$freq};
}
# Average speed should be as a percentage as well. So divide it by the max freq.
my $max_freq = (sort { $a <=> $b } keys %{$freq_p{$cpu}})[-1];
if (defined($max_freq) && $max_freq > 0)
{
	printf "cpuspeed_avg.value %d\n", $freq_p{avg}{$cpu} / $max_freq * 100;
}

# Save state!
eval { lock_nstore($cpufreq_now, $statefile) };
if ($@)
{
	print STDERR "[$0] Error writing state file!\n";
}

exit 0;