On Wed, Jan 13, 2010 at 10:25:01AM -0500, Graham Kelly wrote: > Hi, > > Optimizations such as 5+7 into 13 really don't get you much. ZEND_ADD (and > other basic opcodes) are not in any way a slow point in a program. And > unfortunately to be able to optimize these you would probably need to put in > an extra pass in the compiler which would probably just slow things down > (unless you have a LOT of these types of additions). > > As for the foo() example... This looks very simple however it is actually a > very hard problem that would most likely take far more time and resources to > solve in the compiler then it would to just leave it be. The problem here is > that you need to understand everywhere that $a is assigned a value and its > value is used. The problem becomes very hard in other functions that have > loops and other types of control structures. It really just ends up > becomming a fairly complex mess to solve. > > The same can be said about quite a few of the other optimizations you can > think of. On the surface they seem simple (and a few of them actually are) > but most of them are complex... largely do to some of the unique 'features' > of PHP. > > In any case, optimization in PHP is not a lost cause. The first thing you > should really do is be using an opcode cache such as APC. Other than that
Unfortunately: APC does not work with PHP 5.3 -- I have a site where I would love to use it but I cannot. I use APC to great effect elsewhere. Can anyone say when APC will be fixed for PHP 5.3, what about it being ready for PHP 6 ? > there are some solutions being worked on. There is Zend Optimizer and there > is pecl/optimizer (which to warn you is probably far from being stable). > There are also a few efforts to compile PHP such as the PHC compiler. > > Overall though, more often than not PHP is not the bottleneck of your > program and thus optimization wont get you too much. -- Alain Williams Linux/GNU Consultant - Mail systems, Web sites, Networking, Programmer, IT Lecturer. +44 (0) 787 668 0256 http://www.phcomp.co.uk/ Parliament Hill Computers Ltd. Registration Information: http://www.phcomp.co.uk/contact.php Past chairman of UKUUG: http://www.ukuug.org/ #include <std_disclaimer.h> -- PHP Internals - PHP Runtime Development Mailing List To unsubscribe, visit: http://www.php.net/unsub.php
