Vastly Overzealous GC on Android

Question

I'm developing a game for Android, and am having huge (and unpredictable) issues with the garbage collector.

During one phase of loading, we allocate about 18,000 1616 byte arrays (some chunked up level data). Sometimes, but not always, the garbage collector will decide to run a sweep after every single allocation, slowly increasing the heap size:

06-13 13:51:59.362  16941-17640/com.lp.aeronautical.android D/dalvikvm﹕ GC_FOR_ALLOC freed 0K, 17% free 41923K/50472K, paused 191ms, total 191ms
06-13 13:51:59.362  16941-17640/com.lp.aeronautical.android I/dalvikvm-heap﹕ Grow heap (frag case) to 43.037MB for 1616-byte allocation
06-13 13:51:59.536  16941-17640/com.lp.aeronautical.android D/dalvikvm﹕ GC_FOR_ALLOC freed 0K, 17% free 41926K/50476K, paused 174ms, total 174ms
06-13 13:51:59.536  16941-17640/com.lp.aeronautical.android I/dalvikvm-heap﹕ Grow heap (frag case) to 43.040MB for 1616-byte allocation
06-13 13:51:59.765  16941-17640/com.lp.aeronautical.android D/dalvikvm﹕ GC_FOR_ALLOC freed 0K, 17% free 41931K/50480K, paused 179ms, total 179ms

repeated for all 18,000 allocations. Needless to say this is horrid and makes the game chug badly for a few minutes.

Is there some way to reel in the GC on Android? Or perhaps at least make it grow the heap in larger chunks? (which it normally does just fine).

Answer 1

I ended up converting all of the array allocations to ByteBuffers allocated with ByteBuffer.allocateDirect. This meant I was only making 18000 very small Java heap allocations (just pointers basically), and all of the array memory was stored in native memory.

Moving the big allocations to native memory meant the Dalvik GC no longer noticed the allocations as a problem.