How much the sleep() in the background affect the system resources?

goxu

Hi there,

I'm curious how much the sleep() which is set to no limit can consume the system resource. Could it cause to hang the server? I tried the following and couldnot see the server got busy. Although the browser seemed to be so, if I access to a different page, it responded very quick as usual. It's not a big deal, is it?

sleep.php

<?php
set_time_limit(0);
sleep(0);
?>

fork_sleep.php

<?php
$str = "php -f sleep.php";
exec("$str > /dev/null &");
?>

MarkR

I think you'll find sleep(0) sleeps for no time, not forever.

Keeping a process permanently running in the background is not going to make you popular with your systems admin. A single process may not slow down the machine (much), but it still uses memory and creating enough of them will cause the system to grind to a halt.

I've used this technique in the past but only with strict locking / checking to ensure that there is never more than one process created.

Mark

goxu

MarkR wrote:
I've used this technique in the past but only with strict locking / checking to ensure that there is never more than one process created.

That is exactly what I meant to do. I'd like to diminish my script's process as much as possible.

OK, let me get to the point. If I make it a loop forever with some sleep and do thousands of jobs within the loop, and comparing to just simply executing thousands of scripts by creating the corresponding numbers of processes, which one is more likely to be considerd an abuse by system admins?

dougal85

Don't most server set-up's have a maximum execution time? I think mine is 30 seconds, I created a infinate loop by mistake once.

Then the server kills the process.

goxu

dougal85 wrote:
Don't most server set-up's have a maximum execution time? I think mine is 30 seconds, I created a infinate loop by mistake once.

Then the server kills the process.

indeed....