RE: [PHP-DEV] Patch for opcode caches

> -----Original Message----- > From: Marcus Boerger [mailto:helly@php.net] > Sent: Friday, March 14, 2008 8:24 PM > To: Stas Malyshev > Cc: Dmitry Stogov; Andi Gutmans; phpxcache; internals@lists.php.net > Subject: Re: [PHP-DEV] Patch for opcode caches > > > Hello Stanislav, > > Friday, March 14, 2008, 5:51:49 PM, you wrote: > > >> But that means we are compiling inheritance when a file is loaded > >> form the cache. The goal should be to compiling inheritance when > >> writing to the opcode cache file. All we achieve here is a > slow down. > >> If there is > > > You can not do that. You do not know that until runtime. > > >> something that makes this required than at least we need > to warn the > >> user about the slow code. I Think what we need to do is > deprecating > >> class and > > > It won't be slow. It would be much faster (in some cases > 10x faster). > > This specific assembly of instructions might be slower in > some cases, > > but the code altogether will be faster. That's the idea of > the opcode > > caches. > > >> namespace use in non main blocks as well as include and require in > >> non main blocks. And if there is no such case than > everything can be > >> bound early which is the fast state we should aim for. > > Lemme just think, doing inheritance at compile time before we > send the stuff to an opcode cache can be slower then? It's always faster, but with opcode caches we cannot always do it in compile-time, because the parent (in another file) might be changed on next load of children class. > How is > that possible? After all late binding means we do it at run > time. And no matter how much faster we can do it. It will > always be slower than doing the same thing only once. > > > We do not need to deprecate anything, and inheritance can > not be bound > > before parent class is known, which in the case of bytecode > cache means > > - not before the file is loaded from the cache. That's > exactly what this > > patch enables. It does not change performance > characteristics of neither > > cached not non-cached code, it just makes it much simpler > and working in > > all cases. > > Inheritance cannot be done before the parent class is known. > We still need to do the prototype checks even if we assume > the class is there and insert a virtual class as parent somehow. Right. This is the reason why we need to delay early binding. But we don't like to delay it to run-time, because it will breake the class creaton order and as result may breake some scripts. Thanks. Dmitry.