As for the renice function by leandro dot pereira at gmail dot com, this isn't true. pcntl_setpriority() doesn't set the nice level of a process, but instead sets the base priority of it. At first glance this might seem like the same thing, but on a system level, they are actually quite different.
In fact, if you're looking to use pcntl_setpriority() to prioritize your process (a tool or a daemon or what-not), I wouldn't recomend using setpriority at all, but renice it instead. Let the system manage priorities and you'll end up with the results you were looking for.
This applies only to POSIX based systems only (as does the function presented by leandro dot pereira at gmail dot com as well).
pcntl_setpriority
(PHP 5, PHP 7, PHP 8)
pcntl_setpriority — Change the priority of any process
Description
pcntl_setpriority() sets the priority of
process_id.
Parameters
-
priority -
priorityis generally a value in the range-20to20. The default priority is0while a lower numerical value causes more favorable scheduling. Because priority levels can differ between system types and kernel versions, please see your system's setpriority(2) man page for specific details. -
process_id -
If
null, the process id of the current process is used. -
mode -
One of
PRIO_PGRP,PRIO_USER,PRIO_PROCESS,PRIO_DARWIN_BGorPRIO_DARWIN_THREAD.
Return Values
Returns true on success or false on failure.
Changelog
| Version | Description |
|---|---|
| 8.0.0 |
process_id is nullable now.
|
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User Contributed Notes 2 notes
t dot stobbe at blackdogdev dot com ¶
18 years ago
leandro dot pereira at gmail dot com ¶
19 years ago
The following snippet may be used under older versions of PHP to provide similar functionality. Tested only under Linux.
<?php
function _pcntl_setpriority($priority, $pid = 0)
{
$priority = (int)$priority;
$pid = (int)$pid;
if ($priority > 20 && $priority < -20) {
return False;
}
if ($pid == 0) {
$pid = getmypid();
}
return system("renice $priority -p $pid") != false;
}
?>
