What version of the platform are you running on? It looks like in the current source most of the function is written in native code, but there is no native code in your profiling. I don't work on Dalvik, so I don't know when the native impl appeared.
If this is the original Harmony implementation, it is probably way over-engineered and inefficient. :) If your numbers are normally of the form "xxxxx.yyy" you could try writing your own parser that parses that form as efficiently as possible, and bail to the generic impl if it finds something it can't handle. You certainly should be able to write something that doesn't have a $#&^%!! StringBuilder involved (good ghod!). On Thu, Apr 14, 2011 at 11:43 AM, Paul <pmmen...@gmail.com> wrote: > Ah, I see, create a kind of mapping from String -> float, and first > check the mapping before performing the conversion? > > Here is what traceview is telling me for the calls to Float.valueOf(): > > java/lang/Float.valueOf (Ljava/lang/String;)Ljava/lang/Float; > * self = 1.9% > * java/lang/Float.parseFloat (Ljava/lang/String;)F = 94.3% > > ** self = 1.3% > ** org/apache/harmony/luni/util/FloatingPointParser.parseFloat (Ljava/ > lang/String;)F = 98.7% > > *** self = 6.5% > *** org/a.../h.../luni/util/FloatingPointParser.initialParse (Ljava/ > lang/String;I)Lorg/a.../h.../luni/util/FloatingPointParser > $StringExponentPair = 58.7% > > **** self = 29.9% > **** a bunch of StringBuilder calls ~= 60% > > *** java/lang/String.toLowerCase ()Ljava/lang/String = 26.8% > > * java/lang/Float.valueOf (F)Ljava/lang/Float; = 3.8% > > ** self = 48.4% > ** java/lang/Float.<init> (F)V = 51.2% > > *** self = 69.7% > *** java/lang/Number.<init> ()V = 30.3% > > Paul > > On Apr 14, 2:20 pm, Dianne Hackborn <hack...@android.com> wrote: > > I think this may be what Marcin was suggesting -- if the same float value > > tends to appear multiple times, then when you parse a new one put it into > a > > cache. When you read strings, first see if the string is already in the > > cache to retrieve the previously parsed float value for it. > > > > Also can you get profiling data for where most of the time is spent > inside > > of Float.parseFloat()? In at least the current code base, the bulk of > the > > work for that is already done in native code. It would be interesting to > > know if most of your time is spent in that native function or the glue > > around it. > > > > It would also be useful to know what kind of CPU and what OS version you > are > > testing this on. For example, the JIT in newer platforms may > significantly > > improve performance here; CPUs that don't have hardware floating point > > support may have significantly worse performance. > > > > > > > > On Thu, Apr 14, 2011 at 9:17 AM, Paul <pmmen...@gmail.com> wrote: > > > The XML is the storage venue - Paths are drawn to the screen from the > > > XML, and users can add new Paths (written back to the XML) or delete > > > existing Paths (data is deleted from XML). > > > > > On Apr 14, 12:11 pm, Marcin Orlowski <webnet.andr...@gmail.com> wrote: > > > > > Any suggestions welcome! > > > > > > How often the source data changes? Do you reuse it later? If so and > > > source > > > > data changes not too often, cache it (write down processed data for > > > further > > > > reuse). If changes more frequently does it change totally or just is > > > small > > > > portion? If the latter, process only what's new. And cache it again. > > > > > > Regards, > > > > Marcin Orlowski > > > > > > *Tray Agenda <http://bit.ly/trayagenda>* - keep you daily schedule > > > handy... > > > > *Date In Tray* <http://bit.ly/dateintraypro> - current date at > glance... > > > > WebnetMobile on *Facebook <http://webnetmobile.com/fb/>* and > > > > *Twitter<http://webnetmobile.com/twitter/> > > > > * > > > > > -- > > > 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 > > > > -- > > Dianne Hackborn > > Android framework engineer > > hack...@android.com > > > > Note: please don't send private questions to me, as I don't have time to > > provide private support, and so won't reply to such e-mails. All such > > questions should be posted on public forums, where I and others can see > and > > answer them. > > -- > 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 > -- Dianne Hackborn Android framework engineer hack...@android.com Note: please don't send private questions to me, as I don't have time to provide private support, and so won't reply to such e-mails. All such questions should be posted on public forums, where I and others can see and answer them. -- 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
