(PHP 5, PHP 7, PHP 8)

proc_niceModificar la prioridad del proceso actual


proc_nice(int $increment): bool

proc_nice() modifica la prioridad del proceso actual por la cantidad especificada en increment. Un increment positivo reducirá la prioridad del proceso actual, mientras que un increment negativo la incrementará.

proc_nice() no está relacionada con proc_open() y sus funciones asociadas en ninguna forma.



El valor de incremento del cambio de prioridad.

Valores devueltos

Devuelve true en caso de éxito o false en caso de error. Si ocurre un error, como que el usuario carezca de permisos para modificar la prioridad, un error de nivel E_WARNING es generado también.


Nota: Disponibilidad

proc_nice() existirá únicamente si su sistema tiene soporte para 'nice'. 'nice' está definido de acuerdo a los estándares: SVr4, SVID EXT, AT&T, X/OPEN, BSD 4.3. Esto quiere decir que proc_nice() no está disponible en Windows.

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User Contributed Notes 5 notes

11 years 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:


//decrease niceness

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

php at richardneill dot org
13 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"
13 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.
phil_php at zieaon dot com
3 years ago
It is important to note that this is a relative change. I didn't read the description properly and couldn't figure out why setting proc_nice(0) didn't take the forked children back to 0!
For example if you run:
proc_nice(0); // will have no effect
proc_nice(5); // will take the niceness back to 0


In PHP CLI under Debian (and probably many other Linux flavours) you can read the 'niceness' from the proc filesystem. (There may be a PHP command that gives this info but there doesn't seem to be a link to it on this page.)
= intval(explode(" ",file_get_contents("/proc/".getmypid()."/stat"))[18]);

// Note: Older versions of Linux return an unsigned integer which has to be converted to a signed integer.
$Current_Niceness_Value = unpack("l",pack("L",intval(explode(" ",file_get_contents("/proc/".getmypid()."/stat"))[18])))[1];

pandi at home dot pl
15 years ago
Simple function for check process nice, by default returns nice of current process:


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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