Android 原生库和内存消耗

Question

I'm participating in development of an Android application that uses quite heavy native library (~20Mb). Actual problem is that GC is working very frequently to resume some (but not too much) memory. Multiple times per second.

04-10 12:16:05.391  18940-18951/com.some.demo D/dalvikvm﹕ GC_FOR_ALLOC freed 6120K, 29% free 31708K/44359K, paused 20ms, total 20ms
04-10 12:16:05.501  18940-18951/com.some.demo D/dalvikvm﹕ GC_FOR_ALLOC freed 6121K, 29% free 31708K/44359K, paused 23ms, total 23ms
04-10 12:16:05.601  18940-18951/com.some.demo D/dalvikvm﹕ GC_FOR_ALLOC freed 6120K, 29% free 31708K/44359K, paused 23ms, total 23ms
04-10 12:16:05.702  18940-18951/com.some.demo D/dalvikvm﹕ GC_FOR_ALLOC freed 6120K, 29% free 31708K/44359K, paused 25ms, total 25ms
04-10 12:16:05.802  18940-18951/com.some.demo D/dalvikvm﹕ GC_FOR_ALLOC freed 6120K, 29% free 31708K/44359K, paused 28ms, total 28ms
04-10 12:16:05.902  18940-18951/com.some.demo D/dalvikvm﹕ GC_FOR_ALLOC freed 6120K, 29% free 31708K/44359K, paused 28ms, total 28ms
04-10 12:16:06.002  18940-18951/com.some.demo D/dalvikvm﹕ GC_FOR_ALLOC freed 6120K, 29% free 31708K/44359K, paused 26ms, total 26ms
04-10 12:16:06.122  18940-18951/com.some.demo D/dalvikvm﹕ GC_FOR_ALLOC freed 6120K, 29% free 31708K/44359K, paused 41ms, total 41ms

In Android Device Monitor (Heap tab) tool I can see that >25 MB is allocated by 1-byte array (byte[], boolean[]) , other parts consuming much lower heap. In Allocation Tracker I can see a lot of lines with 3133456 byte[] for dalvik.system.NativeStart .

It raises a question: does Android load all native library into memory or am I doing something wrong? I need some good explanation how Android deals with native libraries.

If there is no really effective way to reduce heap space taken by native library (removing dependency isn't an option, because not only Android uses it), then is there any other way to lower frequency of GC?

EDIT: Adding images to provide more information.

Heap space:

Memory allocation:

Answer 1

I'm posting references that can be useful for those who will experience the same problems and lack of information on topic.

I've found an answer here https://stackoverflow.com/a/11312145/955107 that states: A GC_FOR_ALLOC is by itself not a sign of a problem in your application however:

• Android applications start with a small heap which grows (up to a point) when applications require more and more memory, and a GC_FOR_ALLOC is done before increasing the size of the heap. In this case GC_FOR_ALLOC is perfectly normal.
• If you allocate memory faster than the concurrent GC has time to free it up, GC_FOR_ALLOC is inevitable. And there's nothing inherently wrong with allocating memory faster than the concurrent GC can free up memory.

Also a very useful source of information is video by Patrick Dubroy. It gave me more understanding what is happening in my application and what I need to analyze in my code: Google I/O 2011: Memory management for Android Apps . Special attention to questions and answers on 53 minute 5 seconds and 55 minute 42 seconds.