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Date: Sun, 16 Aug 2009 22:04:57 +0100
Message-ID: <af54caaf0908161404w74c733bbu2e45dfdf8ec6f52e@mail.gmail.com>
To: Tom Boutell <tom@punkave.com>
Cc: Lothar Scholz <scholz@scriptolutions.com>, internals@lists.php.net
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Subject: Re: Re[5]: [PHP-DEV] Design of the Zend Engine's Instruction Set
From: paul.biggar@gmail.com (Paul Biggar)

Hi Tom,

On Sun, Aug 16, 2009 at 7:16 PM, Tom Boutell<tom@punkave.com> wrote:
> Re: the performance of PHP, if it's badly implemented, shouldn't
> Quercus (a reimplementation of PHP in Java) run rings around it?
>
> In reality, Quercus is faster than PHP without APC, but with APC the
> Quercus team themselves admit it only "roughly matches" the original
> PHP in speed.

Having spent a few years working on a PHP compiler (phc  -
phpcompiler.org), I can suggest a few reasons for this. Mostly, its
hard to get fast when you have a small team. The effort involved in
even making a language match the underspecified, ad-hoc nature of
PHP's reference implementation is staggering. Roadsend seem to have
the same problem.

Secondly, all of PHP's libraries are similarly specified. They are all
written using the Zend API, and there are about 5000 functions. A
compelling reimplementation must reimplement large portions of this.
Its no small challenge.


In short, I believe the lack of great speedups from other PHP
implementations (including my own) can be attributed at least
partially to the implementation difficulty and under-specification of
PHP the language.


Paul

-- 
Paul Biggar
paul.biggar@gmail.com