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(PHP 5 >= 5.1.3)
sys_getloadavg — Ermittelt durchschnittliche Systemlast
Gibt drei Messwerte zurück die die durchscnittliche Systemlast (die Anzahl der Prozesse in der Ausführungswarteschlange) über die jeweils letzten 1, 5 und 15 Minuten representieren.
Gibt ein array mit den drei Messwerten der letzten 1, 5 und 15 Minuten zurück.
Beispiel #1 sys_getloadavg() Beispiel
<?php
$load = sys_getloadavg();
if ($load[0] > 80) {
header('HTTP/1.1 503 Too busy, try again later');
die('Serverlast zu hoch, versuchen Sie es später noch einmal.');
}
?>
Hinweis: Diese Funktion ist auf Windows-Plattformen nicht implementiert.
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.');
}
}
}
?>
To get just current load avg, you can do :
<?php
$output = shell_exec('cat /proc/loadavg');
$loadavg = substr($output,0,strpos($output," "));
?>
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.
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);
}
}
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).
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