[debian] navit: rendering is slow

Ed Kapitein ed at kapitein.org
Fri Dec 26 16:40:14 CET 2008

Hi arne anka,

Just as a reference:
I use navit on OM2008.12 and for short route's (~ 10 Km)  it works just
for longer routes (~ 100 Km ) CPU usage goes to 90% and it becomes
*very* unresponsive.
So please try with a short route first.

Kind regards,

Davide Scaini wrote:
> 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 ;-) ?
> d
> 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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