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sys_getloadavg

(PHP 5 >= 5.1.3)

sys_getloadavg — 获取系统的负载（load average）

说明

array sys_getloadavg ( void )

返回三个系统负载（系统运行队列中的进程数）的样本数据，分别是1分钟、5分钟和15分钟之前。

返回值

返回一个包含1分钟、5分钟和15分钟之前采样数据的array。

范例

Example #1 sys_getloadavg() 的例子

<?php
$load = sys_getloadavg();
if ($load[0] > 80) {
    header('HTTP/1.1 503 Too busy, try again later');
    die('Server too busy. Please try again later.');
}
?>

注释

Note: 此函数未在 Windows 平台下实现。

杂项 函数
在线手册：中文 英文
PHP手册
PHP手册 - N: 获取系统的负载（load average）

用户评论:

rick at rctonline dot nl (24-Jan-2012 08:57)

Here is another one that also works on windows. Note that this method is not fast, so be careful in the number of calls to this function.

<?php
function get_server_load() {
   
        if (stristr(PHP_OS, 'win')) {
       
            $wmi = new COM("Winmgmts://");
            $server = $wmi->execquery("SELECT LoadPercentage FROM Win32_Processor");
           
            $cpu_num = 0;
            $load_total = 0;
           
            foreach($server as $cpu){
                $cpu_num++;
                $load_total += $cpu->loadpercentage;
            }
           
            $load = round($load_total/$cpu_num);
           
        } else {
       
            $sys_load = sys_getloadavg();
            $load = $sys_load[0];
       
        }
       
        return (int) $load;
   
    }
?>

828586 at gmail dot com (12-Jun-2010 03:43)

equivalent for windows
<?php
ob_start();
passthru('typeperf -sc 1 "\processor(_total)\% processor time"',$status);
$content = ob_get_contents();
ob_end_clean();
if ($status === 0) {
    if (preg_match("/\,\"([0-9]+\.[0-9]+)\"/",$content,$load)) {
        if ($load[1] > get_config('busy_error')) {
            header('HTTP/1.1 503 Too busy, try again later');
            die('Server too busy. Please try again later.');
        }
    }
}
?>

Anonymous (19-Nov-2009 08:14)

To get just current load avg, you can do :

<?php
$output = shell_exec('cat /proc/loadavg');
$loadavg = substr($output,0,strpos($output," "));
?>

scott at corelevel dot com (27-Nov-2006 10:47)

I was having a problem with a large script I need to run - was a loop through about 50,000 records and downloading several pictures for a bunch of them, and updating the database.

the problem came as I started getting visitors to my site, the server would get behind, run out of memory, iowait skyrockets, mysql slows down... was a total downhill spiral.

Use this to fix it.

$load = sys_getloadavg();
$sleep=5;
$maxload=2;
if ($load[0] > $maxload) {
       sleep($sleep);
    echo "Busy server - sleep $sleep seconds<br>";
}

I have to play with the load and the sleep number to find what worked for my script, but now my server does not bog at all.

surfchen at gmail dot com (06-Jul-2006 05:22)

the codes below will provide this function for order versions of PHP.
if (!function_exists('sys_getloadavg')) {
    function sys_getloadavg()
    {
        $loadavg_file = '/proc/loadavg';
        if (file_exists($loadavg_file)) {
            return explode(chr(32),file_get_contents($loadavg_file));
        }
        return array(0,0,0);
    }
}

tom pittlik (03-Mar-2006 10:36)

The code below mimics the output of sys_getloadavg(). You may have to tweak the way the substring is captured for different distros.

<?

function sys_getloadavg_hack()
{
    $str = substr(strrchr(shell_exec("uptime"),":"),1);
    $avs = array_map("trim",explode(",",$str));

    return $avs;
}

print_r(sys_getloadavg_hack());

// Array
// (
//     [0] => 6.24
//     [1] => 4.92
//     [2] => 3.99
// )

?>

This function is a neat way of running low priority or non-essential cron jobs on a busy server - if the load is high, don't continue with the task (and try again in a few minutes time).