Actually, I haven't seen confirmation that Dalvik even has a JIT, much less a "reasonably good" one. I know it's been "talked about".
But I haven't really caught up to the latest yet. On Aug 19, 12:54 pm, Amit <[email protected]> wrote: > Hi Dan, > > Thanks for the response > > > In general, JITed Java code is as fast as or faster than the > > equivalent native code, if the JIT is reasonably good, and if the > > specific application can be coded efficiently in Java. > > I was actually banking on this. I don't know too much of the hairy > details (am not really a compiler person), but from what I have read > recent improvements by Google to the Dalvik VM make it *comparable* if > not equal in performance to native code ... > > Hate to sound like I'm harping on the same stuff, but then (assuming > that the JVM/JIT compiler is doing good enough), the memory bottleneck > still remains. > > Thanks, > Amit > > On Aug 19, 10:11 pm, DanH <[email protected]> wrote: > > > In general, JITed Java code is as fast as or faster than the > > equivalent native code, if the JIT is reasonably good, and if the > > specific application can be coded efficiently in Java. The problem is > > that some specific data processing patterns are not easy to code > > efficiently in Java, and I suspect that certain of the bit-bashing > > algorithms used in image processing fall into this category. > > > In such cases the most efficient approach is "native Java", but I only > > know of one JVM (the IBM iSeries "classic" JVM) that permits this, and > > then only for system code. Otherwise it's a bit of a tradeoff to get > > the right partitioning between Java and native, since crossing the > > Java/native boundary tends to be relatively expensive. > > > On Aug 19, 7:03 am, Fabrizio Giudici <[email protected]> > > wrote: > > > > -----BEGIN PGP SIGNED MESSAGE----- > > > Hash: SHA1 > > > > On 8/19/10 13:35 , Amit wrote: > > > > > Now, I know that native code will *not* yield any significant > > > > performance improvement over Java code > > > > Well, specifically for image processing this won't be true, for sure > > > up to 2.1 included (as the bytecode is purely interpreted); in 2.2 we > > > have JIT, but can't speak as I haven't seen it yet. > > > > - -- > > > Fabrizio Giudici - Java Architect, Project Manager > > > Tidalwave s.a.s. - "We make Java work. Everywhere." > > > java.net/blog/fabriziogiudici -www.tidalwave.it/people > > > [email protected] > > > -----BEGIN PGP SIGNATURE----- > > > Version: GnuPG/MacGPG2 v2.0.14 (Darwin) > > > Comment: Using GnuPG with Mozilla -http://enigmail.mozdev.org/ > > > > iEYEARECAAYFAkxtHakACgkQeDweFqgUGxe83wCfSDP1NEN+TLD0iOCZ/zSvQDRw > > > I5cAoJOEoC7eREU5KuPU7m93/GDj9VUr > > > =2ZDf > > > -----END PGP SIGNATURE----- -- You received this message because you are subscribed to the Google Groups "Android Developers" group. To post to this group, send email to [email protected] To unsubscribe from this group, send email to [email protected] For more options, visit this group at http://groups.google.com/group/android-developers?hl=en
