PHP: proc_nice

Description

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.

Parameters

increment: The increment value of the priority change.

Return Values

Returns TRUE on success or FALSE on failure. If an error occurs, like the user lacks permission to change the priority, an error of level E_WARNING is also generated.

Notes

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.

User Contributed Notes
proc_nice

php at riggers dot me dot uk
12-Aug-2004 06:20


Just an addition to the previous note re: exec('renice...'). The exit_func() will not set the priority back to normal (0) (at least on linux), unless the user that the webserver is running as is a super user (bad idea). You can decrease the priority of the running task, but not increase it again. See man page for renice.



To prevent subsequent requests running at the lower priority I called apache_child_terminate() on shutdown.

griph at dd dot chalmer dot se
10-Nov-2003 04:34


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');

?>