Re: About optimization for compiler

> Am 27.02.2015 um 07:53 schrieb Xinchen Hui <laruence@gmail.com>: > > Hey: > > On Fri, Feb 27, 2015 at 2:22 PM, Xinchen Hui <laruence@gmail.com > <mailto:laruence@gmail.com>> wrote: >> Hey Internals: >> >> I was looking Bob's switch optimization.. > And, I am not against this switch optimization.. > > I referring it to show where is my concerns came from > > thanks >> >> then I start to worry about where is the place optimization should goes.. >> >> in generally, PHP is a interpreted language. IMO, it should >> compiler the PHP codes to opcode without any optimization(of course, >> we did some, but they won't change a lots of opcodes which should be >> generated).. >> >> and, since 5.5, we already have opcache bundled in.. >> >> thus, I am proposing a principle, that is: >> >> in the future, we only do optimization in opcache side, and keep >> Zend Compiler without any optimization... considering Zend Compiler do >> things in -O0. >> >> since, optimization always are dangerous.. if we only do them in >> opcache, user can still run them codes with disable opcache, or at >> least disable some optimization level which cause that.. >> >> what do you think? >> >> thanks >> >> -- >> Xinchen Hui >> @Laruence >> http://www.laruence.com/ > > > > -- > Xinchen Hui > @Laruence > http://www.laruence.com/ > <http://www.laruence.com/> Hmm. I'm not sure, but do we really want to have the optimizations depending on opcache? I'd rather shift to slowly adding the optimizations into Zend/, in separate compiler steps you can (like in opcache too) enable and disable. It's actually a bit weird to have to include opcache just for its optimizations. Opcache should do what its name says: the sole task of caching the op_arrays. We need to change an extension for nearly every little change in Zend/. That shouldn't be the case either. But just to say, it's not only a minor optimization, in a real world stateful parser it makes a difference of a few percent. And also, this optimization only adds a ZEND_SWITCH opcode, nothing more. (except in case we can determine at compile-time where the switch land, then it will be optimized out to a simple JMP) Bob