proc_nice

说明

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.

参数

increment: The increment value of the priority change.

返回值

如果成功则返回 TRUE，失败则返回 FALSE。 If an error occurs, like the user lacks permission to change the priority, an error of level E_WARNING is also generated.

注释

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.

add a note User Contributed Notes

php at riggers dot me dot uk
13-Aug-2004 07:20


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
11-Nov-2003 06:34


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');

?>

add a note