[debian] navit: rendering is slow

Davide Scaini dscaini at gmail.com
Fri Dec 26 15:06:34 CET 2008

might it be an issue of graphical drivers?
I experienced that rendering everything on debian is so slow...
just an example: i use mplayer from terminal to listen my music (if
you have some more usable solution just let me know!) and rendering
the numbers of percentage growing takes abot 50% of cpu... that's
crazy! so i keep open another tab (of terminal) to switch there and
let mplayer work calmly...
I tried om2008.12 and animations are really fluid... nothing compared
with previous om versions... might it be a kernel issue? something
that we can copy on debian ;-) ?

On Fri, Dec 26, 2008 at 12:35 PM, Fox Mulder <Quakeman1 at gmx.net> wrote:
> arne anka wrote:
>> i enabled the small screen gui ("internal" it is called, i think) and
>> tried out navigation.
>> so far rendering is _very_ slow and the cpu usage applet always shows
>> about 80-100% usage -- thus eating power quite fast, i presume.
>> it takes a long while (and someinteraktion) to make the current map to
>> appear, even after gps obtained a fix i had to swith to some dilog and
>> back to the map view to make it rerender.
>> after the map was there and navigation hints appeared i made the
>> matchbox-keyboard appear which took up the upper part of the screen. after
>> disabling the keyboard the part of the navit window remained grey (though
>> the window's top bar was redrawn immediately by xfce), after several
>> minutes the small rectangles were redrawn -- but that was about all,
>> navigation information ("turn in ... meters") seemed not related to my
>> current position anymore and the map never was redrawn while the cpu usage
>> was still exceptionally high.
>> after about 15min i killed navit.
>> navit is 0.1.0+svn-1791, built without speech, map is the eu.bin linked to
>> in the navit wiki.
> If you installed the precompiled navit version i would suggest to
> compile it from source yourself. I don't know why, but the precompiled
> version runs very bad on my fr with debian. After i compiled my own
> version (1778) it runs much better. I also had trouble with very high
> cpu usage but with my new compiled version i got quite low cpu usage
> when navit is idle.
>> my questions so far:
>> - is navit's navigation usable at all on a device so limited? (other
>> experiences?)
> I tried routing between two nearby towns (~6km) and it worked quite good.
>> - is the high cpu usage rather a bug or an unavoidable side effect because
>> of the fr's little mind?
> I think this is some kind of bug with the precompiled versions in
> conjunction with debian.
>> - is there a tweak to make rendering more responsive (eg by rendering less
>> detailed?)
> You have to enable the fast-map-drag patch by hand. Therefor you have to
> add drag_bitmap="1" to the navit tag (like recent_dest) in navit.xml.
> Ciao,
>     Rainer
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