APC cache fragmentation only value for monitoring service

apcfrag.php

<?php 
ini_set('display_errors',1);
ini_set('error_reporting', E_ALL);

header("Cache-Control: no-store, no-cache, must-revalidate");
header("Cache-Control: post-check=0, pre-check=0", false);
header("Pragma: no-cache"); 

// default display mode
//$display_mode='formatted';
$display_mode='other';

// default cache mode
$cache_mode='opcode';

// cache scope
$scope_list=array(
	'A' => 'cache_list',
	'D' => 'deleted_list'
);

$time = time();

if(!function_exists('apc_cache_info') || !($cache=@apc_cache_info($cache_mode))) {
	echo "SYSTEM OK No cache info available. Check APC is running.\n";
	exit;
}

if (isset($_GET['clear'])){
	apc_clear_cache();
	apc_clear_cache('user');
	apc_clear_cache('opcode');	
}

function bsize($s) {
	foreach (array('','K','M','G') as $i => $k) {
		if ($s < 1024) break;
		$s/=1024;
	}
	return sprintf("%5.1f %sBytes",$s,$k);
}

$cache_user = apc_cache_info('user', 1);  
$mem=apc_sma_info();
if(!$cache['num_hits']) { $cache['num_hits']=1; $time++; }

// Fragementation: (freeseg - 1) / total_seg
$nseg = $freeseg = $fragsize = $freetotal = 0;
for($i=0; $i<$mem['num_seg']; $i++) {
	$ptr = 0;
	foreach($mem['block_lists'][$i] as $block) {
		if ($block['offset'] != $ptr) {
			++$nseg;
		}
		$ptr = $block['offset'] + $block['size'];
		
		//Only consider blocks <5M for the fragmentation %
		if($block['size']<(5*1024*1024)) $fragsize+=$block['size'];
			$freetotal+=$block['size'];
	}
	$freeseg += count($mem['block_lists'][$i]);
}
	
switch ($display_mode) {
	case "formatted": $frag = ($freeseg > 1)? sprintf("%.2f%% (%s out of %s in %d fragments)", ($fragsize/$freetotal)*100,bsize($fragsize),bsize($freetotal),$freeseg) : "0%"; break;
	default: $frag = ($freeseg > 1)? sprintf("%.2f%", ($fragsize/$freetotal)*100,bsize($fragsize),bsize($freetotal),$freeseg) : 0;	break;
}	


if ($frag >= 0){
	if ($frag > 60){
		apc_clear_cache();
		apc_clear_cache('user');
		apc_clear_cache('opcode');
		
		echo "SYSTEM OK and APC cache fragmentation at: ".$frag."% and now reset.\n";
	} else {
		echo "SYSTEM OK and APC cache fragmentation at: ".$frag."% \n";
	}	
} else {
	echo "SYSTEM OK No cache info available. Check APC is running.\n";
}
?>

Code modified from original apc.php (Ralf Becker, Rasmus Lerdorf, Ilia Alshanetsky) - mainly for use with any monitoring tool to alert if the fragmentation level is too high.