SourceForge has been redesigned. Learn more.

cpu usage and batterie drain with Android

  • fireball4

    fireball4 - 2013-05-05

    Hello guys,

    actually I'm changing my mobile device from symbian (Nokia E52) to Android (Motorala Defy). Therefore I have to switch from gpsmid.jar to gpsmid.apk. The last years I was cosseted with the long batterie duration of my Nokia mobile, of course it wasn't a touch screen device and had a smaller screen than my new android. But I was surprised about the high cpu usage with GPSMID without any map moving. Means I zoomed in my map to e.g. 25m scale, turned GPS off, and left the android mobile alone without any map moving, showing only a area of meadow. With that situation I was thinking the mobile cpu shouldn't have anything to do (nothing to calculate), but I was wrong. The app SetVsel told me that GPSMID uses all the time 100% of my 1GHz cpu, but why? Is this normal? Can I do something about it to save more batterie power? I don't need the display on all the time, but I need to record my tracks. But for that task the permanent usage of a 1GHZ cpu at 100% is to much?! Has someone the same experience? And has someone a hint for me to restrict battery drain of GPSMID? I think 14 hours of permanent track recording should be possible with an android device, too, without a change of the battery?! Am I so wrong?

  • sk750

    sk750 - 2013-05-05

    Hmm, I'm almost always using GpsMid for routing but I'm now rather happy with the battery time using GpsMid. With a full battery and the mobile being in flight mode I think I could do routing for about 5 hours. This is much more than on my old Symbian device. Can't tell why GpsMid would use 100% CPU. In either case it's important to turn on area outlines in the properties file and to be sure it's really used, also turn off triangle format which is necessary only for j2me devices.

  • fireball4

    fireball4 - 2013-05-05

    Thanks again sk750. OK, 5 hours with the display constantly on, sounds normally. However for hiking or biking it's not enough, but it seems to be the unhappy truth for android devices. I don't no if my Nokia had 100% cpu usage with GPSMID, too.  But it lasts definitely some hours longer, I guess 10 hours. OK, I dont know a CPU measurement tool for symbian. However, I did forget to set triangleAreaFormat = false for android within my properties file. I will have a look how this setting the cpu usage might change?! But, I've wondered about odd artefacts within plain areas, like forests or meadows. It's very likely that those artifacts came from this setting, which I not needed before, because like I said, I came from symbian. At the other hand I've tried uncompressed maps und ziped maps an my SD-card, but it seems there is no cpu-usage differents for unpacking an big (300MB) zip file. The map build up speed on my android phone seemed to be the same.

  • sk750

    sk750 - 2013-05-21

    Hello fireball4, I've now checked CPU usage of GpsMid on an Android 4.1.2 dual core device with an app called GSam Battery Monitor which can show the cpu usage in the status bar at the top. On my device it does not seem there's such a high CPU usage - if the device is not moving there almost seems to be no CPU usage, so I guess on slower devices all the CPU is taken to draw the map. Did turning off the area triangle format make any difference for you?

  • fireball4

    fireball4 - 2013-05-21

    Hello sk750, yes I turned the area triangle format off. With that setting plain areas like forests or meadows where drawn smooth.

    if the device is not moving there almost seems to be no CPU usage

    It seems you are right even with my single cpu mobile, too.
    But one strange behavior I have observed. When I start GPSMID and the map will not be moved  in the first place all buildings were redrawn ever an ever. This means when I turn GPS off and start GPSMID buldings and some other small areas (e.g. playground, some meadows and parking areas) begin to blink until I or GPS moves the map. This continuous drawing of that areas causes high cpu usage.

  • sk750

    sk750 - 2013-05-25

    That sounds a bit like the option "Simplify map when busy" that jkpj implemented a while ago - maybe if you uncheck this in Setup/Map the flickering is gone?


Log in to post a comment.