That was my thinking exactly - from the trace, a HUGE portion (~80%!) of the conversion time is spent on string operations that wouldn't seem to be needed. I couldn't find any link to a native routine via the traceview.
On Apr 14, 3:26 pm, Kostya Vasilyev <[email protected]> wrote: > What do String.toLowerCase(String) and StringBuilder have to do with > parsing a floating point number? > > -- Kostya > > 14.04.2011 22:43, Paul пишет: > > > > > 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<[email protected]> 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<[email protected]> 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<[email protected]> 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 [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 > >> -- > >> Dianne Hackborn > >> Android framework engineer > >> [email protected] > > >> 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. > > -- > Kostya Vasilyev --http://kmansoft.wordpress.com -- 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
