PHP教學-自動偵測 cpu 使用率( linux )

本次介紹 linux 版偵測系統 cpu 使用率，該範例程式僅能在 linux 系統上執行，windows 環境無法執行。

<?php
/* Gets individual core information */
function GetCoreInformation() {
    $data = file('/proc/stat');     // proc資料的路徑
    $cores = array();
    foreach( $data as $line ) {
        if( preg_match('/^cpu[0-9]/', $line) ) //利用正規表達示過濾 cpu 數量
        {
            $info = explode(' ', $line );
            $cores[] = array(
                'user' => $info[1],
                'nice' => $info[2],
                'sys' => $info[3],
                'idle' => $info[4]
            );
        }
    }
    return $cores;
}
/* compares two information snapshots and returns the cpu percentage */
function GetCpuPercentages($stat1, $stat2) {
    if( count($stat1) !== count($stat2) ) {
        return;
    }
    $cpus = array();
    for( $i = 0, $l = count($stat1); $i < $l; $i++) {
        $dif = array();
        $dif['user'] = $stat2[$i]['user'] - $stat1[$i]['user'];
        $dif['nice'] = $stat2[$i]['nice'] - $stat1[$i]['nice'];
        $dif['sys'] = $stat2[$i]['sys'] - $stat1[$i]['sys'];
        $dif['idle'] = $stat2[$i]['idle'] - $stat1[$i]['idle'];
        $total = array_sum($dif);
        $cpu = array();
        foreach($dif as $x=>$y) $cpu[$x] = round($y / $total * 100, 1);
        $cpus['cpu' . $i] = $cpu;
    }
    return $cpus;
}
/* get core information (snapshot) */
$stat1 = GetCoreInformation();
/* sleep on server for one second */
sleep(1);
/* take second snapshot */
$stat2 = GetCoreInformation();
/* get the cpu percentage based off two snapshots */
$data = GetCpuPercentages($stat1, $stat2);
/* makes a google image chart url */
function makeImageUrl($title, $data) {
    $url = 'http://chart.apis.google.com/chart?chs=440x240&cht=pc&chco=0062FF|498049|F2CAEC|D7D784&chd=t:';
    $url .= $data['user'] . ',';
    $url .= $data['nice'] . ',';
    $url .= $data['sys'] . ',';
    $url .= $data['idle'];
    $url .= '&chdl=User|Nice|Sys|Idle&chdlp=b&chl=';
    $url .= $data['user'] . '%25|';
    $url .= $data['nice'] . '%25|';
    $url .= $data['sys'] . '%25|';
    $url .= $data['idle'] . '%25';
    $url .= '&chtt=Core+' . $title;
    return $url;
}
/* ouput pretty images */
foreach( $data as $k => $v ) {
    echo '<img src="' . makeImageUrl( $k, $v ) . '" />';
}