proc_nice

(PHP 5)

proc_niceChange the priority of the current process

Descrizione

bool proc_nice ( int $increment )

proc_nice() changes the priority of the current process by the amount specified in increment. A positive increment will lower the priority of the current process, whereas a negative increment will raise the priority.

proc_nice() is not related to proc_open() and its associated functions in any way.

Elenco dei parametri

increment

The increment value of the priority change.

Valori restituiti

Restituisce TRUE in caso di successo, FALSE in caso di fallimento. If an error occurs, like the user lacks permission to change the priority, an error of level E_WARNING is also generated.

Note

Nota: Availability

proc_nice() will only exist if your system has 'nice' capabilities. 'nice' conforms to: SVr4, SVID EXT, AT&T, X/OPEN, BSD 4.3. This means that proc_nice() is not available on Windows.

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User Contributed Notes 5 notes

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1
kevin AT REMOVETHIS mrkmg.com
1 year ago
On a Linux system, running apache2 as a non-privileged user you can not increase the niceness of the process after decreasing it. Also, you can not use the apache_child_ terminate either. I found the following does work though:

<?php

//decrease niceness
proc_nice(19);

//kill child process to "reset" niceness
posix_kill( getmypid(), 28 );

?>
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0
Marek
3 years ago
Regarding ionice - on linux the impact of the ionice -c3 class is similar to that of nice, because the CPU "niceness" is taken into account when calculating the io niceness.
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0
php at richardneill dot org
4 years ago
If a process is reniced, then all its children inherit that niceness. So a PHP script can call proc_nice on itself, then invoke system(), and the command executed via system() will also be niced.

Also worth making a note of ionice. There's no PHP function for this, but it's important. A nice'd program will happily try to chew up all i/o bandwidth with very little CPU usage, it can therefore make the entire computer non-responsive despite the programmer's intention.  Use "ionice -c3"  or see "man ionice"
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0
pandi at home dot pl
5 years ago
Simple function for check process nice, by default returns nice of current process:

<?php

public static function getProcessNice ($pid = null) {
    if (!
$pid) {
       
$pid = getmypid ();
    }
       
   
$res = `ps -p $pid -o "%p %n"`;
       
   
preg_match ('/^\s*\w+\s+\w+\s*(\d+)\s+(\d+)/m', $res, $matches);
       
    return array (
'pid' => (isset ($matches[1]) ? $matches[1] : null), 'nice' => (isset ($matches[2]) ? $matches[2] : null));
}

?>
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0
griph at dd dot chalmer dot se
11 years ago
If you don't have PHP5 and needs to nice your process this works good.

<?php

function proc_nice($priority) {
 
exec("renice +$priority ".getmypid());
}

//You also need a shutdown function if you don't want to leave your http deamons with a modified priority
function exit_func(){
 
// Restore priority
 
proc_nice(0);
}

register_shutdown_function('exit_func');
?>
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