Re: [ZEND-ENGINE-CVS] cvs: ZendEngine2 / zend_execute.c

On Fri, 16 Jul 2004 12:15:46 -0400, Ilia Alshanetsky <ilia@prohost.org> wrote: > On July 16, 2004 11:58 am, Thies C. Arntzen wrote: > > hey ilia, > > > > here's another one of my meaningess, synthetic benchmarks (this is how > > the CreatorsOfPHP(tm) would call them) > > > > ackermann(8) (source on request - highly recursive) > > Recursive functions in PHP are inherently dangerous as without proper limits > they will rather quickly ~5671 iterations with a basic function a() { a(); } > (PHP 4/5). > By comparison the same code only takes 2897 iterations before the patch. While > the patch does not solve this crash it reduces it's chances by nearly 50% > (unexpected benefit). > > More over the crash problem that the patch solves is not theoretical that I > made up because I have nothing better to do. We have at least 2 confirmed bug > reports by different people and surely there are others who came across this > issue and didn't report it. > > Yes, you are correct, with a dedicated benchmark specifically designed to > "exploit" the allocation routine change there is a performance drop, but > surely stability is more important then speed. If that is not that case, > there are a whole lot of optimizations we can perform, but that'd mean users > will need to write their code extra carefully :-), which as we know is not > going to happen. php has no real concept for out-of-memory situations (stack or real) - nor do we catch infinite (nor too deep) recursions. allowing for "deeper" recursion doesn't really fix anything. so, i think we should either come up with a real solution or leave it as it is. i have to say that i do care if we're making the genreal case slower, even if it's a tiny bit... re, -tc