php教程

sys_getloadavg

(PHP 5 >= 5.1.3, PHP 7)

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

说明

sys_getloadavg ( void ) : array

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。

User Contributed Notes

stanislav dot eckert at vizson dot de 18-Jan-2016 05:15
Function to get current CPU load as percentage value under Windows and Linux.

Note: Function is getServerLoad(). It will return a decimal value as percentage of current CPU load or NULL if something went wrong (e. g. insufficient access rights).

<?php

    header("Content-Type: text/plain");

    function _getServerLoadLinuxData()
    {
        if (is_readable("/proc/stat"))
        {
            $stats = @file_get_contents("/proc/stat");

            if ($stats !== false)
            {
                // Remove double spaces to make it easier to extract values with explode()
                $stats = preg_replace("/[[:blank:]]+/", " ", $stats);

                // Separate lines
                $stats = str_replace(array("\r\n", "\n\r", "\r"), "\n", $stats);
                $stats = explode("\n", $stats);

                // Separate values and find line for main CPU load
                foreach ($stats as $statLine)
                {
                    $statLineData = explode(" ", trim($statLine));

                    // Found!
                    if
                    (
                        (count($statLineData) >= 5) &&
                        ($statLineData[0] == "cpu")
                    )
                    {
                        return array(
                            $statLineData[1],
                            $statLineData[2],
                            $statLineData[3],
                            $statLineData[4],
                        );
                    }
                }
            }
        }

        return null;
    }

    // Returns server load in percent (just number, without percent sign)
    function getServerLoad()
    {
        $load = null;

        if (stristr(PHP_OS, "win"))
        {
            $cmd = "wmic cpu get loadpercentage /all";
            @exec($cmd, $output);

            if ($output)
            {
                foreach ($output as $line)
                {
                    if ($line && preg_match("/^[0-9]+\$/", $line))
                    {
                        $load = $line;
                        break;
                    }
                }
            }
        }
        else
        {
            if (is_readable("/proc/stat"))
            {
                // Collect 2 samples - each with 1 second period
                // See: https://de.wikipedia.org/wiki/Load#Der_Load_Average_auf_Unix-Systemen
                $statData1 = _getServerLoadLinuxData();
                sleep(1);
                $statData2 = _getServerLoadLinuxData();

                if
                (
                    (!is_null($statData1)) &&
                    (!is_null($statData2))
                )
                {
                    // Get difference
                    $statData2[0] -= $statData1[0];
                    $statData2[1] -= $statData1[1];
                    $statData2[2] -= $statData1[2];
                    $statData2[3] -= $statData1[3];

                    // Sum up the 4 values for User, Nice, System and Idle and calculate
                    // the percentage of idle time (which is part of the 4 values!)
                    $cpuTime = $statData2[0] + $statData2[1] + $statData2[2] + $statData2[3];

                    // Invert percentage to get CPU time, not idle time
                    $load = 100 - ($statData2[3] * 100 / $cpuTime);
                }
            }
        }

        return $load;
    }

    //----------------------------

    $cpuLoad = getServerLoad();
    if (is_null($cpuLoad)) {
        echo "CPU load not estimateable (maybe too old Windows or missing rights at Linux or Windows)";
    }
    else {
        echo $cpuLoad . "%";
    }

?>
kexianbin at diyism dot com 28-May-2014 10:35
Use this:
<?php
$loads=sys_getloadavg();
$core_nums=trim(shell_exec("grep -P '^physical id' /proc/cpuinfo|wc -l"));
$load=$loads[0]/$core_nums;
echo $load;
?>
vladvarna at gmail dot com 18-Jul-2012 02:51
You can emulate loadavg using this. Can also be used to get iowait

<?php
   function ProcStats()
   {   
       $fp=fopen("/proc/stat","r");
       if(false===$fp)
               return false;
       $a=explode(' ',fgets($fp));
       array_shift($a); //get rid of 'cpu'
       while(!$a[0])
           array_shift($a); //get rid of ' '
       var_dump($a);
       fclose($fp);
       return $a;
   }

   $a=ProcStats();
   sleep(5);
   $b=ProcStats();

  
   $total=array_sum($b)-array_sum($a);
  
   $loadavg = round(100* (($b[0]+$b[1]+$b[2]) - ($a[0]+$a[1]+$a[2])) / $total, 2); // user+nice+system
   $iowait= round(100* ($b[4] - $a[4])/$total,2);

?>
rick at rctonline dot nl 24-Jan-2012 12:57
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 07:43
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 12:14
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 02:47
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 09:22
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 02:36
The code below mimics the output of sys_getloadavg(). You may have to tweak the way the substring is captured for different distros.

<?php

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).

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