You didn't post all the code needed to debug, so we guess.

while loop just continues forever.

Usually when I see complain about this in threaded apps, it involves the threads never returning( ending ). You might want to look at Simple threaded chat server . Look at the if($client->connected)....or else close $client. Depending on your code, you might also look at the $select->can_read and $select->can_write methods, and put them in an if-block.