Native shared library loaded to slow in Android

Question

I have a shared library placed in libs/armeabi folder. It is loaded using

System.loadLibrary("library_name.so");

The size of the library is around 3MB. The loading time is very long. It sometimes last almost 20 seconds. It blocks my GUI. I tried to put System.loadLibrary("library_name.so"); in a different thread but my GUI is still blocked. I know that others apps use even bigger .so files, but the loading time is not so big. What could be the problem?

EDIT

3MB was the size of the debug version. Release version is about 800KB, but the problem is the same. Some additional info:

.so contains my two c++ libraries which are circularly connected
running arm-linux-androideabi-nm -D -C -g library_name.so displays a lot of functions and variables
I don't use LOCAL_WHOLE_STATIC_LIBRARIES anymore
here are the section headers table obtained by using arm-linux-androideabi-readelf-tool:

Section Headers:
  [Nr] Name              Type            Addr     Off    Size   ES Flg Lk Inf Al

  [ 0]                   NULL            00000000 000000 000000 00      0   0  0

  [ 1] .dynsym           DYNSYM          00000114 000114 00b400 10   A  2   1  4

  [ 2] .dynstr           STRTAB          0000b514 00b514 015b0c 00   A  0   0  1

  [ 3] .hash             HASH            00021020 021020 004d1c 04   A  1   0  4

  [ 4] .rel.dyn          REL             00025d3c 025d3c 006e98 08   A  1   0  4

  [ 5] .rel.plt          REL             0002cbd4 02cbd4 000468 08   A  1   6  4

  [ 6] .plt              PROGBITS        0002d03c 02d03c 0006b0 00  AX  0   0  4

  [ 7] .text             PROGBITS        0002d6f0 02d6f0 08e6e0 00  AX  0   0  8

  [ 8] .ARM.extab        PROGBITS        000bbdd0 0bbdd0 00bad0 00   A  0   0  4

  [ 9] .ARM.exidx        ARM_EXIDX       000c78a0 0c78a0 005b80 08  AL  7   0  4

  [10] .rodata           PROGBITS        000cd420 0cd420 005cc0 00   A  0   0  4

  [11] .data.rel.ro.loca PROGBITS        000d46d8 0d36d8 0006e4 00  WA  0   0  4

  [12] .fini_array       FINI_ARRAY      000d4dbc 0d3dbc 000008 00  WA  0   0  4

  [13] .init_array       INIT_ARRAY      000d4dc4 0d3dc4 00009c 00  WA  0   0  4

  [14] .data.rel.ro      PROGBITS        000d4e60 0d3e60 00384c 00  WA  0   0  8

  [15] .dynamic          DYNAMIC         000d86ac 0d76ac 000100 08  WA  2   0  4

  [16] .got              PROGBITS        000d87ac 0d77ac 000854 00  WA  0   0  4

  [17] .data             PROGBITS        000d9000 0d8000 000648 00  WA  0   0  8

  [18] .bss              NOBITS          000d9648 0d8648 047271 00  WA  0   0  8

  [19] .comment          PROGBITS        00000000 0d8648 000026 01  MS  0   0  1

  [20] .note.gnu.gold-ve NOTE            00000000 0d8670 00001c 00      0   0  4

  [21] .ARM.attributes   ARM_ATTRIBUTES  00000000 0d868c 00002d 00      0   0  1

  [22] .shstrtab         STRTAB          00000000 0d86b9 0000d8 00      0   0  1

How many methods are in the library? How are you registering them with JNI (via `RegisterNatives` or by giving them `Java_` names)? — fadden, Feb 20 '13 at 01:50
@fadden I have 5 exported functions. They are registered using RegisterNatives(). These methods use functions from my c++ library. Maybe the problem could be that whole c++ library is included in my .so file? — sinisha, Feb 20 '13 at 08:40
@fadden I used a tool suggested in _auseln_'s answer. It showed that alot of functions are registered. I think the problem occurss because I'am using `LOCAL_WHOLE_STATIC_LIBRARIES` and cant't build my project without it — sinisha, Feb 20 '13 at 10:15

auselen · Answer 1 · 2013-02-20T10:22:28.110

1

Try to reduce number of exported functions in your shared library. You can use

arm-linux-androideabi-nm -D -C -g library_name.so

and check if that list is unnecessarily long, and remove the ones that you don't use (declare them static). You can look up nm's manual by $man nm and read about how to use and interpret it.

If you need to use lots of functions, use RegisterNatives() to register your functions instead of relying on name mangling and lookup - that's what you do when you give your functions names like Java_your_path_YourClass_yourFunction.

You can also try to strip (arm-linux-androideabi-strip) your library, if it has symbols.

To avoid blocking UI, you can try to load your shared library early in a different thread and wait for it.

I wouldn't use LOCAL_WHOLE_STATIC_LIBRARIES, if exposing static libraries is not what I ultimately want.

LOCAL_WHOLE_STATIC_LIBRARIES

These are the static libraries that you want to include in your module without allowing the linker to remove dead code from them.

This is mostly useful if you want to add a static library to a shared library and have the static library's content exposed from the shared library.

Try to fix that problem instead of working around some build problem.

edited Feb 20 '13 at 10:22

answered Feb 20 '13 at 07:34

auselen

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I have 5 exported functions. They are registered using RegisterNatives(). Where should I use this `arm-linux-androideabi-nm -D -C -g library_name.so` ? – sinisha Feb 20 '13 at 08:43
If you didn't run it how do you know how many exported functions you have? – auselen Feb 20 '13 at 09:25
1

You can find that nm in ndk. – auselen Feb 20 '13 at 09:25
No. You should check so file with nm. – auselen Feb 20 '13 at 09:55
I got a really a lot of data after running this tool. In those 5 functions mentioned earlier I use functions from my c++ libraries. I couldn't build my project without setting `LOCAL_WHOLE_STATIC_LIBRARIES`. I think this is causing the problem – sinisha Feb 20 '13 at 10:11
@sinisha updated my answer. I don't think I can help you much than this. – auselen Feb 20 '13 at 10:23
Thanks again for your advises. They were useful. – sinisha Feb 20 '13 at 10:41

score 1 · Accepted Answer · answered Mar 18 '13 at 08:55

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The problem is static initialization in some constructor which takes to much time to finishis

answered Mar 18 '13 at 08:55

sinisha

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Native shared library loaded to slow in Android

2 Answers2