I am loading 3d models (1MB - 10MB) into memory which takes a long time (20 sec for 1.5MB model). When I look at the logs I see that the garbage collector constantly frees memory and pauses. See below for the logs:
07-20 17:37:25.340: D/dalvikvm(2826): GC_FOR_ALLOC freed <1K, 8% free 79443K/85575K, paused 86ms
07-20 17:37:25.350: I/dalvikvm-heap(2826): Grow heap (frag case) to 78.511MB for 852408-byte allocation
07-20 17:37:25.450: D/dalvikvm(2826): GC_FOR_ALLOC freed <1K, 8% free 80275K/86471K, paused 95ms
07-20 17:37:25.550: D/dalvikvm(2826): GC_FOR_ALLOC freed <1K, 8% free 80275K/86471K, paused 85ms
07-20 17:37:25.550: I/dalvikvm-heap(2826): Grow heap (frag case) to 79.325MB for 852408-byte allocation
07-20 17:37:25.660: D/dalvikvm(2826): GC_FOR_ALLOC freed <1K, 8% free 81108K/87367K, paused 96ms
07-20 17:37:25.760: D/dalvikvm(2826): GC_FOR_ALLOC freed 0K, 8% free 81108K/87367K, paused 87ms
07-20 17:37:25.760: I/dalvikvm-heap(2826): Grow heap (frag case) to 80.137MB for 852408-byte allocation
07-20 17:37:25.870: D/dalvikvm(2826): GC_FOR_ALLOC freed <1K, 8% free 81940K/88263K, paused 98ms
07-20 17:37:26.060: D/dalvikvm(2826): GC_CONCURRENT freed <1K, 5% free 83988K/88263K, paused 3ms+12ms
07-20 17:37:26.200: D/dalvikvm(2826): GC_FOR_ALLOC freed <1K, 5% free 84715K/88263K, paused 120ms
07-20 17:37:26.200: I/dalvikvm-heap(2826): Grow heap (frag case) to 83.660MB for 852312-byte allocation
07-20 17:37:26.310: D/dalvikvm(2826): GC_FOR_ALLOC freed 0K, 5% free 85547K/89159K, paused 102ms
07-20 17:37:26.420: D/dalvikvm(2826): GC_FOR_ALLOC freed <1K, 5% free 85547K/89159K, paused 95ms
07-20 17:37:26.420: I/dalvikvm-heap(2826): Grow heap (frag case) to 84.473MB for 852312-byte allocation
07-20 17:37:26.520: D/dalvikvm(2826): GC_FOR_ALLOC freed <1K, 5% free 86379K/90055K, paused 105ms
07-20 17:37:26.640: D/dalvikvm(2826): GC_FOR_ALLOC freed <1K, 4% free 87212K/90055K, paused 117ms
07-20 17:37:26.650: I/dalvikvm-heap(2826): Grow heap (frag case) to 86.098MB for 852312-byte allocation
...
Is it possible to postpone the garbage collection until after the model is loaded. Any other performance tips are welcome as well :)
No, this is not possible, the virtual machine handles this and it's not changeable. But to speed up loading the models you could consider using serialized objects instead of the .3ds/.obj/... files. They will load faster and use less memory.
Check the wiki about jpct and serialized objects.