get how much physical CPU resources really used from ppc64 Linux running on LPAR of Power Systems

purr.pl

#!/usr/bin/perl

# calcurate average physical CPU usage from Processor Utilization Resources Register, aka PURR.
# see URL below in detail.
# http://www.ibm.com/developerworks/wikis/display/LinuxP/Entries+in+the+proc+Filesystem

use strict;
use warnings;

$| = 1;

my $timebase;
my $fh;
my $interval = $ARGV[0];
unless ($interval) {
	print "./purr.pl interval\n";
	exit(1);
}

sub get_purr {
	my $purr;
	open $fh, "/proc/ppc64/lparcfg" or die;
	while (<$fh>) {
		next unless (/^purr=(\d+)$/);
		$purr = $1;
	}
	close $fh;
	chomp $purr;
	return $purr;
}

open $fh, "/proc/cpuinfo" or die;
while (<$fh>) {
	next unless (/^timebase\s+:\s+(\d+)$/);
	$timebase = $1;
	last;
}
chomp $timebase;
#print "timebase = $timebase\n";
close $fh;

print <<END;

smt=On

physc
-----
END

my ($purr, $purr0, $delta);
while (1) {
	$purr = get_purr;
	if ($purr0) {
		$delta = $purr - $purr0;
#		print "$purr0\t$purr\t$delta\t$timebase\t$interval\t", sprintf("%.4f", $delta/$timebase/$interval), "\n";
		print sprintf("%.2f", $delta/$timebase/$interval), "\n";
	}
	sleep $interval;
	$purr0 = $purr;
}