Speed? (and compiling... :)

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Hi there!

I was wondering about the speed of PHP recently (5 mins ago).

So, can someone tell me how efficient PHP is with large scripts? Let's say, you have 100k of code distributed over 10 included files and 5 classes... Is there a major drawback in performance?

I mean, if i understood everything, PHP has to open and interpret ALL scripts on EVERY hit to the page utilizing these, right? There is not JIT compiling or caching done whatsoever?

I believe this HAS to be a serious hit on performance espacially if numerous accesses take place at the same time (well visited pages, e.g.), as parsing sourcecode is very time-consuming (i presume).

Are there any serious comparisons on that matter, perhaps against JSP (you know they're compiled on first access) or has anyone done some research in that direction? Because i'd really like to know if my code or e.g. the DB-connection is slowing down my pages!

And besides, has anyone (i mean the php developers in the first place) ever thought of compiling PHP-Scrips on the fly like JSP does? I'd expect that to be an enourmous boost to speed, but what do i know... :-/

Thx in advance for your uncountable replies! =)

feldon23

And besides, has anyone (i mean the php developers in the first place) ever thought of compiling PHP-Scrips on the fly

There are a half dozen PHP caching systems including Zend Optimiser and PHPAccelerator.

LonelyPixel

i've recently measured my board system:

200kB source code in ~20 files (mostly included) take about 100 to 130 ms on my home server (no load), a celeron 733 on win2k.

the same test at my webhoster (something like pentium 1.2-2.0 GHz, don't know, but normally heavily loaded) took about 30 ms.

both tested with php4 (4.3.2 / 4.2.3).

compiling php scripts on first access? sounds good, but how shall that work? this must be done by the zend engine, right?

Weedpacket

Originally posted by LonelyPixel
compiling php scripts on first access? sounds good, but how shall that work? this must be done by the zend engine, right?

Well, considering Zend have just such a product.... Of course, there are other points in the process where caching can be done; and they're not necessarily exclusive of each other.

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Originally posted by Weedpacket
Well, considering Zend have just such a product.... Of course, there are other points in the process where caching can be done; and they're not necessarily exclusive of each other.

Of course, the files themselves could be cached to avoid reloading unchanged sources.

But wth is PHP completely interpreted? As all commands, expressions and functions have to be translated to 'internal', let's say 'bytecode', why not store a complete compile on hd and keep it in memory while unchanged?

PHP seems to be pretty fast for an interpreted language, but it could whip a llamas ass if treated similar to JSP. And i don't think of a bulky VM, just a relatively effortless kind of caching that doesn't alter the way development and deployment is done today.

That could especially help with the upcoming PHP5 and the expected drawbacks in performance caused by the OO...

superwormy

PHP scripts are compiled on every access, the Zend Performance Suite offers script caching, and script compiling ( compiled on first access, recompiled after you make a change to the script )

There are other products ( PHP Accelerator comes to mind ) that do the same thing as the Zend products as well.