On Wed, Sep 9, 2009 at 10:39 PM, Eddie Drapkin<oorza2k5@xxxxxxxxx> wrote: > On Wed, Sep 9, 2009 at 10:32 PM, APseudoUtopia <apseudoutopia@xxxxxxxxx> wrote: >> Hey list, >> >> I have a php cli script that listens on a UDP socket and, when data is >> sent to the socket, the script inserts it into a database. I'm using >> the real BSD socket functions, not fsock. >> >> The script runs socket_create(), then socket_bind(). Then it starts a >> while(TRUE) loop. Within the loop, it runs socket_recvfrom(). I have >> it running 24/7 inside a screen window. >> >> I'm curious as to the cpu/memory/etc usage of a while(true) loop. The >> `top` command shows that the process is in the sbwait state (the OS is >> FreeBSD). I'm contemplating adding a usleep or even a sleep inside to >> loop. Would this be beneficial? I'm not too sure of how the internals >> of PHP work in terms of loops and such. >> >> Thanks. >> >> -- >> PHP General Mailing List (http://www.php.net/) >> To unsubscribe, visit: http://www.php.net/unsub.php >> >> > > Is your socket blocking? If so, what's the timeout? > > while(true) { > > //wait for socket timeout > > } > > is the same as: > > while(true) { > > //read nothing from socket and sleep > > } > > Without the usleep(), the loop is going to loop as fast as your CPU > will let it - meaning 100% CPU usage, all the time, at least in linux, > although I'm pretty sure BSD would behave the same. > > As far as I'm aware, sockets in PHP behave almost identically to the > way that they behave in C. I had an asynchronous TCP server written > with the socket_* functions and noticed that the while(true) loop used > 100% of the CPU because of the nonblocking sockets in use, but a > usleep() solved that quite easily. Using blocking sockets with > socket_select and a sane timeout relieved the high CPU usage as well. > I believe it is blocking. Here's my socket_recvfrom: $Recv = socket_recvfrom($Socket, $Data, 512, MSG_WAITALL, $Name, $Port); So I think the the MSG_WAITALL is causing it to block until incoming data connection is closed (it never reaches the 512 byte mark before it echos the data). Here's the full script, minus the debugging/error catching stuff: $Socket = socket_create(AF_INET, SOCK_DGRAM, SOL_UDP); $Bind = socket_bind($Socket, '127.0.0.1', 1223); while(TRUE){ $Recv = socket_recvfrom($Socket, $Data, 512, MSG_WAITALL, $Name, $Port); print_r($Data); } As soon as the message is sent on the socket, it displays it. There's no delay until it builds up 512 bytes or anything. Also, I was playing around with ps and it looks like it's using 0% CPU, so I suppose it must be blocking. In the case that it is blocking, would it still be wise to throw a usleep in there just to be sure? Thanks. -- PHP General Mailing List (http://www.php.net/) To unsubscribe, visit: http://www.php.net/unsub.php
