You really , really need to use filtering routines that are fixed point, and put them in C using the NDK, and you will get a huge speed boost!
-niko On Apr 22, 2:53 pm, fadden <fad...@android.com> wrote: > On Apr 22, 8:02 am, BobG <bobgard...@aol.com> wrote: > > > [...] I timed a bunch of floating > > point adds and multiplies in a loop, and I was getting about a million > > per sec (dev phone 2, 528mhz cpu?). (I see the Linpack app in the > > market gives the same result) This is many times faster than sw > > floating point on a 20mhz AVR, but I bet its way slower than hw fp. > > Does the fp multiply in java multiply 2 32 bit floats, or promote them > > to doubles like c does? > > Java and Dalvik bytecode have independent mul-float and mul-double > instructions. On the VFP-enabled hardware I've had my hands on, the > performance difference is negligible. On devices with soft float, > it's more substantial. > > The VM will use VFP if present. (This is one of the basic arguments > in favor of just-in-time vs. static compilation -- if you did this in > native code you'd have to provide two versions.) The core of the > interpreter is hand-coded ARM assembly, so on VFP devices it would > actually be slower to call out to a library. > > We're always interested in good JIT compiler benchmarks. If you have > an APK or stand-alone executable that does a bunch of computationally > intensive stuff and spits out numbers, put it up somewhere and we'll > poke at it. I don't know if we're allowed to talk about performance > numbers yet (the JIT hasn't shipped yet), but we can hand-wave > something. :-) > > -- > You received this message because you are subscribed to the Google > Groups "Android Developers" group. > To post to this group, send email to android-developers@googlegroups.com > To unsubscribe from this group, send email to > android-developers+unsubscr...@googlegroups.com > For more options, visit this group > athttp://groups.google.com/group/android-developers?hl=en -- You received this message because you are subscribed to the Google Groups "Android Developers" group. To post to this group, send email to android-developers@googlegroups.com To unsubscribe from this group, send email to android-developers+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/android-developers?hl=en
