On Sat, Sep 11, 2010 at 8:50 PM, Shawn McKenzie <nos...@mckenzies.net> wrote:
> On 09/10/2010 11:13 AM, J Ravi Menon wrote:
>> Hi,
>>
>> I have some basic questions on running php (5.2.x series on Linux
>> 2.6) as a standalone daemon using posix methods (fork() etc..):
>>
>> #!/usr/bin/php
>> <?php
>>
>> require_once ('someclass.php');
>>
>> // do some initializations
>> .
>>
>> // main 'forever' loop - the '$shutdown' will
>> // be set to true via a signal handler
>>
>> while(!$shutdown)
>> {
>> $a = new SomeClass();
>>
>> $a->doSomething()
>>
>> }
>>
>> // shutdown logic.
>>
>> The 'someclass.php' in turn will include other files (via require_once).
>>
>> The above file will be executed directly from the shell. The main loop
>> could be listening to new requests via sockets etc..
>>
>> Few questions:
>>
>> 1) Does opcode cache really matter in such cli-based daemons? As
>> 'SomeClass' is instantiated at every loop, I am assuming it is only
>> compiled once as it has already been 'seen'.
>> I am not very clear on how apc (or eaccelerator) works in such cases.
>>
>>
>> 2) What about garbage collection? In a standard apache-mod-php setup,
>> we rely on the end of a request-cycle to free up resources - close
>> file descriptiors, free up memory etc..
>> I am assuming in the aforesaid standalone daemon case, we would
>> have to do this manually? In the loop above, would it be better to
>> 'unset($a)' explicitly at the end of it before
>> it goes to the next iteration?
>>
>> Note: I have written pre-forker deamons in php directly and
>> successfully deployed them in the past, but never looked at in depth
>> to understand all the nuances. Anecdotally, I have
>> done 'unset()' at some critical places were large arrays were used,
>> and I think it helped. AFAIK, unlike Java, there is no 'garbage
>> collector' thread that does all the magic?
>>
>> Thanks,
>> Ravi
>
> If I have time when you reply I'll answer the questions, but I must ask:
> Is this purely academic? Why is this a concern? Have you encountered
> issues? If so, what?
@Tom: I have compiled php with pcntl on and this has never been an
issue. It works well (on a linux setup), and I have deployed
standalone daemons with out any major problems. I have a home-grown
'preforker' framework (which I hope to share soon) which can be used
to exploit multi-core boxes.
@Shawn: It is not academic. There is a follow-up I am planning based
on the doubts above. I have deployed such daemons in the past with
some assumptions on (2) by doing manual cleanups - e.g. closing curl
connections, closing up db handles etc... Really want to understand
how php works in such setups outside of apache+mod_php.
thanks,
Ravi
>
> --
> Thanks!
> -Shawn
> http://www.spidean.com
>
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