Rockbox General > Rockbox General Discussion
Portal Player Battery runtime vs compiler
saratoga:
--- Quote from: LambdaCalculus379 on November 02, 2007, 02:52:45 PM ---
--- Quote from: Llorean on November 02, 2007, 02:36:19 PM ---Another point is that on one PortalPlayer CPU (the PP5002 at least) we now perform better than the Apple firmware. It's just our knowledge of the PP502x series that's restraining us.
--- End quote ---
Yes, that's true. I read that now even the 2nd gen iPod surpassed the OF battery life.
If we just had that information for the PP502x series in our hands... datasheets, register values, anything! It seems that the H10 (PP5020) and Sansa e200 (PP5024) are the worst offenders for battery life; solving this issue should help them out immensely.
--- End quote ---
The e200 is actually one of the best PP targets for battery life. I think until the P5002 improvements it was the best. It seems to use less power then the other PP targets, perhaps because the lack of IDE hardware means theres less stuff for us to have improperly initialized.
tychver:
Possibly a stupid question but have any improvements been seen when newer GCC versions were used? The wiki still recommends 4.0.3 for ARM. Didn't 4.2.2 just come out? I noticed the daily builds are still done with it.
Lear:
I just made a quick test using 4.2.2. No big differences that I could see. Build size was about the same (comparing slightly different versions though), and the speed difference (for the codecs I tested) was small. 1-2 percent or so, sometimes faster, sometimes slower. So there's no particular gain by updating the compiler.
tychver:
Just out of interest, which codecs were faster and which were slower? How well does rockbox parallelize across both cores? Last time I was messing around with it I think it had got to the stage of running UI and WPS and kernel on one core and the codec thread on the other.
Is this going to make a big difference to the ammount of work done in parallelizing? It sounds like it: http://gcc.gnu.org/wiki/AutomaticParallelization
Sorry if it's a stupid question; the most complex things I did were hacking up the scroll acceleration patches.
saratoga:
--- Quote from: tychver on November 03, 2007, 10:59:08 PM ---How well does rockbox parallelize across both cores? Last time I was messing around with it I think it had got to the stage of running UI and WPS and kernel on one core and the codec thread on the other.
--- End quote ---
Rockbox does not parallelize across cores yet, except for mpegplayer and the SPC codec (assuming that got committed).
--- Quote from: tychver on November 03, 2007, 10:59:08 PM ---Is this going to make a big difference to the ammount of work done in parallelizing? It sounds like it: http://gcc.gnu.org/wiki/AutomaticParallelization
--- End quote ---
No thats not useful to us, and probably not very useful in general. Autoparallelization is pretty ineffective.
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