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Date: Thu, 1 Apr 2010 13:29:10 -0430
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To: speedy <speedy.spam@gmail.com>
Cc: Rasmus Lerdorf <rasmus@lerdorf.com>, 
	PHP Developers Mailing List <internals@lists.php.net>
Content-Type: multipart/alternative; boundary=00163630faafae992b0483309e32
Subject: Re: [PHP-DEV] php and multithreading (additional arguments)
From: jonah.harris@gmail.com ("Jonah H. Harris")

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On Thu, Apr 1, 2010 at 12:57 PM, speedy <speedy.spam@gmail.com> wrote:

> Now imagine a whole web server written in PHP (ie. nanoserv), say, using
> libevent as the network backend, running the above described real-time web
> implementation. Alternatively, you could perhaps even wire it into
> worker/event
> model of apache/other servers instead of rolling your own. It sounds quite
> powerful,
> and development-effort-wise cheap - out of a mere HTML preprocessor!
>
> With proper threading, this would be a piece of cake to implement in PHP,
> efficiently
> and ensuring low latency, using up all available CPU cores / resources.
>
> Without using native threads, the whole class of web architectures on both
> server
> and processing levels, viewed both separately or together, are quite a bit
> more hairy
> to implement.
>

Sorry, but as a performance-oriented C developer who has written a good
amount of stuff directly against libevent, I'm having a hard time not
laughing at this thread.  Why would anyone want to write such a thing
directly in PHP, or any other scripting language for that matter?  If you're
worried about performance, you're going to have to do it in something either
low-level or that is natively compiled.  In the scripting language world, I
can only think of something like Lua with libevent bindings as being capable
of performing fairly well in a multi-threaded environment (given no GIL).
Though, even in that case, you'd still have a good amount of custom work to
do.

I've worked with libevent-based Comet servers written in C, and there's *no
way* a scripting language version is going to handle memory management,
messaging, and queueing for a large number of connections effectively.
Similarly, you'll never really be able to approach near-real-time processing
in this type of environment given basic
abstraction/interpretation/scheduling issues.

These are very basic systems architecture issues and it's obvious that
scripting languages are *not* designed for what you're asking.  Not to sound
demeaning, but do you have any real need for what you're asking, or are you
just saying, "gee, it would be nice for me to be able to write a Comet
server in 99 lines of PHP that is capable of managing 60K concurrent
connections and a rate of 15K messages/second with a maximum latency of
50ms?"

Sorry, I'm a little grumpy today...

-- 
Jonah H. Harris
Blog: http://www.oracle-internals.com/

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