Check these slides: http://www.onflex.org/ACDS/AS3TuningInsideAVM2JIT.pdf
>From page 43: * We make a simple "hotspot"-like decision about whether to interpret or JIT * Initialization functions ($init, $cinit) are interpreted * Everything else is JIT * Upshot: Don't put performance-intensive code in class initialization Cheers Juan Pablo Califano 2008/7/30, Mark Winterhalder <[EMAIL PROTECTED]>: > > > You clearly understand what I was saying, Mark, but just a brief > > reiteration: compiled ActionScript has to be interpreted by the VM, which > is > > _always_ slower than compiling directly to machine language. > > Yes, I understand and am not even disagreeing. :) > > However, there have been benchmarks where Java was actually marginally > /faster/ than C++ for some specific tests. This seems > counterintuitive, but the JIT compiler knows more at runtime than the > traditional compiler can know in advance, and I'm guessing that's why > it can (not generally, but in some rare situations) do better > optimizations. When you have ideal programmers then of course compiled > languages will be faster, but that difference is getting less as > technology evolves. > But of course we're talking about the Flashplayer here, and size, > portability and start-up time are more important design goals than > execution speed, so we'll most definitely will always have to live > with a very noticeable performance penalty. Then again, we don't have > to manage memory ourselves, which is a big plus. > (Btw memory allocation and optimization: recycling instances where > possible is also a good idea.) > > If somebody knows a good explanation about the when and how of the > AVM2 JIT compiler, I'd be curious. The same goes for a table that > shows relative performance of stuff the renderer does -- like with > alpha vs. without, if rendering time grows linear with the number of > pixels, how much time is wasted on DisplayObjects outside of the > visible Stage, stuff like that. > > Mark > > > > > > On Wed, Jul 30, 2008 at 9:05 PM, Kerry Thompson <[EMAIL PROTECTED]> > wrote: > > Mark Winterhalder wrote: > > > >> Nitpicking, but just as anything digital the SWF opcodes essentially > >> are 1s and 0s, too. :) > > > > Fair enough. Following that to its logical conclusion, _everything_ on > your > > computer is 1s and 0s, including the text in this email ^_^ > > > > You clearly understand what I was saying, Mark, but just a brief > > reiteration: compiled ActionScript has to be interpreted by the VM, which > is > > _always_ slower than compiling directly to machine language. > > > > When I was doing Director full time, I ran some tests that showed C++ to > run > > up to 400 times as fast as Lingo. I lobbied for years to get a true > > machine-language compiler for Lingo, at least for desktop apps. I was > struck > > by how few developers understood the implications, and without other > > developers clamoring for the need for speed, Macromedia never went there. > > Director could have been a major player in the 3D game world. > > > > And don't tell me that Director 3D is "fast enough". Hard-core gamers buy > > $8,000 machines to squeeze every last fps out of their games. With > lights, > > shaders, high-poly objects, multiple cameras, Director is just not fast > > enough for a Quake or Doom LAN party. And, of course, neither is Flash. > > > >> Anyway, the new VM supports JIT compilation to native machine code. I > >> must admit I don't know if /all/ code gets JIT compiled or only > >> hotspots, and I don't know if it will be recompiled for each use to > >> "hardcode" variables, but that would also have implications. > > > > One major implication would be in loops. The complier would have no way > of > > knowing if an array would change length in a loop, for example, so it > > couldn't hard code the length. > > > > Cordially, > > > > Kerry Thompson > > > > _______________________________________________ > > Flashcoders mailing list > > Flashcoders@chattyfig.figleaf.com > > http://chattyfig.figleaf.com/mailman/listinfo/flashcoders > > > _______________________________________________ > Flashcoders mailing list > Flashcoders@chattyfig.figleaf.com > http://chattyfig.figleaf.com/mailman/listinfo/flashcoders > _______________________________________________ Flashcoders mailing list Flashcoders@chattyfig.figleaf.com http://chattyfig.figleaf.com/mailman/listinfo/flashcoders
