sys_getloadavg

(PHP 5 >= 5.1.3, PHP 7, PHP 8)

sys_getloadavg — Gets system load average

Description

sys_getloadavg(): array|false

Returns three samples representing the average system load (the number of processes in the system run queue) over the last 1, 5 and 15 minutes, respectively. Returns false on failure.

Parameters

This function has no parameters.

Return Values

Returns an array with three samples (last 1, 5 and 15 minutes).

Examples

Example #1 A sys_getloadavg() example

<?php
$load = sys_getloadavg();
if ($load[0] > 0.80) {
    header('HTTP/1.1 503 Too busy, try again later');
    die('Server too busy. Please try again later.');
}
?>

Notes

Note: This function is not implemented on Windows platforms.

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User Contributed Notes 13 notes

down

stanislav dot eckert at vizson dot de ¶

8 years ago

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 . "%";
    }

?>

down

rick at rctonline dot nl ¶

12 years ago

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;
    
    }
?>

down

Chris Wheeler ¶

3 years ago

It is important to note that sys_getloadavg() does not return a percentage, and the numbers that it returns are completely meaningless if you do not know the number of CPU cores. To get the number as a percentage you need to divide the value by the number of CPU cores in the system. (eg: if the value is 0.5 and you have two cores, then you are using 25% of the CPU on average). Here is a simple function to get the values as a percent:

<?php
function percentloadavg(){
    $cpu_count = 1;
    if(is_file('/proc/cpuinfo')) {
        $cpuinfo = file_get_contents('/proc/cpuinfo');
        preg_match_all('/^processor/m', $cpuinfo, $matches);
        $cpu_count = count($matches[0]);
    }

    $sys_getloadavg = sys_getloadavg();
    $sys_getloadavg[0] = $sys_getloadavg[0] / $cpu_count;
    $sys_getloadavg[1] = $sys_getloadavg[1] / $cpu_count;
    $sys_getloadavg[2] = $sys_getloadavg[2] / $cpu_count;

    return $sys_getloadavg;
}
?>

down

scott at corelevel dot com ¶

17 years ago

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.

down

Anonymous ¶

14 years ago

To get just current load avg, you can do :



<?php

$output = shell_exec('cat /proc/loadavg');

$loadavg = substr($output,0,strpos($output," "));

?>

down

tom pittlik ¶

18 years ago

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).

down

kexianbin at diyism dot com ¶

10 years ago

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;
?>

down

surfchen at gmail dot com ¶

18 years ago

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);
    }
}

down

828586 at gmail dot com ¶

14 years ago

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.');
        }
    }
}
?>

down

seb dot gibbs at ymail dot com ¶

3 days ago

// To get correct number of CPU cores
// as to calculate correct usage

function getCpuCores() {
    // Linux
    if (stristr(PHP_OS, 'linux')) {
        // First, try /proc/cpuinfo
        if (file_exists('/proc/cpuinfo')) {
            preg_match_all('/^processor/m', file_get_contents('/proc/cpuinfo'), $matches);
            if ($matches[0]) return count($matches[0]);
        }
        // Fallback: Use nproc command
        return (int)shell_exec('nproc');
    }

    // macOS
    if (stristr(PHP_OS, 'darwin')) {
        return (int)shell_exec('sysctl -n hw.physicalcpu');
    }

    // Windows
    if (stristr(PHP_OS, 'win')) {
        // Try wmic command first
        $cpuCount = shell_exec('wmic cpu get NumberOfLogicalProcessors');
        if ($cpuCount) {
            preg_match('/\d+/', $cpuCount, $matches);
            if (isset($matches[0])) return (int)$matches[0];
        }
        // Fallback: Use environment variable
        return (int)getenv('NUMBER_OF_PROCESSORS');
    }

    // If failed
    return false;
}

// Example usage
// get CPU cores
$cores = getCpuCores();

if (is_Numeric($cores)) {
    $corePerc = 100/$cores;
} else {
    $corePerc = 100;
    $cores = 'Unknown';
}
echo '<div><b>CPU:</b> '.$cores .' cores</div>';

// show correct CPU usage
echo '<blockquote>';
$cpu = sys_getloadavg();
echo(round($cpu[0]*$corePerc) .'% - last min<br>');
echo(round($cpu[1]*$corePerc) .'% - last 5 mins<br>');
echo(round($cpu[2]*$corePerc) .'% - last 15 mins<br>');
echo '</blockquote>';

down

-1

Anonymous ¶

3 years ago

simple function to get the cpu load with availability to most os platforms because I haven't actually been able to find a similar protocol if you happen to be testing out various os platforms...

function cpu_load():?string {
    $load='';
    if(strtolower(PHP_OS_FAMILY)=="windows") {
        exec("wmic cpu get loadpercentage /all",$out);
        if($out) {
            foreach($out as $line) {
                if($line&&preg_match("/^[0-9]+\$/",$line)) {
                    $load=$line;
                    break;
                }
            }
        }
    } else {
        $load=sys_getloadavg();
    }
    return $load;
}

down

-2

wowabbs+php at gmail dot com ¶

3 years ago

<?php // Usage processor in Windows using FFI
  if(!dl("ffi")) // Load the extension
    throw new Exception('Cound not load the FFI extension.');

  function GetSystemTimes()
  {
    static $Kernel32;
    $Kernel32??=FFI::cdef(<<<'IDL'
      bool GetSystemTimes(long long *IdleTime, long long *KernelTime, long long *UserTime);
      int GetLastError();
    IDL, 'Kernel32.dll');
    
    $IdleTime   = FFI::new('long long');
    $KernelTime = FFI::new('long long'); // already has idle time
    $UserTime   = FFI::new('long long');
  
    if($Kernel32->GetSystemTimes(FFI::addr($IdleTime), FFI::addr($KernelTime), FFI::addr($UserTime)))
      return [
        'Idle'   =>$IdleTime   ->cdata,
        'Kernel' =>$KernelTime ->cdata, // already has idle time
        'User'   =>$UserTime   ->cdata,
      ];
    return [];
  }
  
  function GetSystemTimesDelta()
  {
    static $Last=null;
    static $Delta=[0,1];
    $Times=GetSystemTimes();
    $Last??=$Times;
    $Idle =$Times['Idle'   ]-$Last['Idle'   ];
    $All  =$Times['Kernel' ]-$Last['Kernel' ]+  // Kernel already has idle time
           $Times['User'   ]-$Last['User'   ];
    if($All>1_000_000) // 100ms
    {
      $Delta=[$Idle, $All];
      $Last=$Times;
    }
    return $Delta;
  }

  function ProcessorLoad()
  {
    static $Load=0;
    [$Idle, $All]=GetSystemTimesDelta();
    if($All>0.0)
      $Load=1-$Idle/$All;
    return $Load;
  }
  
  function KbHit()
  {
    Static $Sys;
    $Sys??=FFI::cdef('bool _kbhit();', 'msvcrt.dll');
    return $Sys->_kbhit();
  }
  
  while(!KbHit())
  {
    echo str_pad((string)round(ProcessorLoad()*100), 3, ' ', STR_PAD_LEFT), "%\n";
    sleep(1);
  }
?>

down

-2

vladvarna at gmail dot com ¶

12 years ago

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);



?>

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