1. Linux
Android
1

2. •
• Web Android (?)
•“ Android”
• Android
• twitter : @checkela
2

3. JAG
3

4. NDK
• JNI • CPU
architecture
• NativeActivity
• OpenGL|ES • Optimization
(1.x,2.x) • NEON
• OpenSL|ES
• Sensor AndroidNDK
7/25
4

5. • Android Linux
• Android Linux
• Linux
• Android ...
http://www.androidproduction.com/
smartphones/the-tablets-can-be-
used-in-honeycomb-mounted-with-
linux.html
5

6. • Linux
• Ubuntu
• Android
• Android Ubuntu
• Android
• ○○○
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•
6

7. http://www.flickr.com/photos/katclay/3934856523/
( )
7

8. Linux
• Android
• CPU
• ( )
• GUI
8

9. • Linux
• Ubuntu
• Android
• Android Ubuntu
• Android
• ○○○
• ○○○
• ○○○
• ○○○
•
9

10. Ubuntu
• Linux
• Linux + GUI +
+ ...
• PC Linux
10

11. • Linux
• Ubuntu
• Android
• Android Ubuntu
• Android
• ○○○
• ○○○
• ○○○
• ○○○
•
11

12. (1/3)
12

13. (2/3)
13

14. (3/3)
14

15. libraries
Application Framework
Application Java JNI
Linux
Application Framework
Linux API
15

16. • Linux
• Ubuntu
• Android
• Android Ubuntu
• Android
• ○○○
• ○○○
• ○○○
• ○○○
•
16

17. Android Ubuntu
Android Ubuntu
2
1
OK
PC
17

18. • Linux
• Ubuntu
• Android
• Android Ubuntu
• Android
• ○○○
• ○○○
• ○○○
• ○○○
•
18

19. Linux
Ubuntu
Android( )
Linux /
19

20. /
•
• Binder(IPC )
•
•
• ApplicationFramework ( logcat)
http://elinux.org/Android_Kernel_Features
20

21. • Linux
• Ubuntu
• Android
• Android Ubuntu
• Android
•
• Binder
•
•
•
21

22. • Linux
•
Ubuntu
http://www.flickr.com/photos/ivanwalsh/4506526865/
22

23. •
• UID:GID
•
SandBox SandBox
sa
A B
http://www.flickr.com/photos/katmere/117444001/
23

24. • Linux
• Ubuntu
• Android
• Android Ubuntu
• Android
•
• Binder
•
•
•
24

25. Binder
• IPC(Internal Procedure Call)
•
• ls | sort -r
• AIDL(Android Interface Definition Language),
Intent
•
http://www.flickr.com/photos/mrvelocipede/501749557/
25

26. Binder
SandBox SandBox
sa
A B
Intent
Intent Intent
AIDL AIDL
Binder
26

27. • Linux
• Ubuntu
• Android
• Android Ubuntu
• Android
•
• Binder
•
•
•
27

28. • Ubuntu
•
...?
28

29. ( )
•
•
• → CPU
29

30. wakelocks
• Sleep !
• )
•
(Java )
PowerManager pm = (PowerManager) getSystemService
(Context.POWER_SERVICE);
PowerManager.WakeLock wakeLock = pm.newWakeLock(
pm.SCREEN_DIM_WAKE_LOCK, "My wakelook");
30

31. • Linux
• Ubuntu
• Android
• Android Ubuntu
• Android
•
• Binder
•
•
•
31

32. Android Ubuntu Linux
512MB 1GB 16GB
(Xperia acro) +swap
32

33. (Android)
•
• ashmem(android shared memory)
• pmem(Physical Memory Allocator)
•
• Out of Memory Handling
• LowMemoryKiller
33

34. (Android)
•
• ashmem(android shared memory)
• pmem(Processor Memory Allocator)
•
• Out of Memory Handling
• LowMemoryKiller
34

35. • ?
• Ubuntu
• OutOfMemory Handling
• Android
• OutOfMemory Handling
• LowMemoryKiller
35

36. Ubuntu
•
• OutOfMemoryHandling
• kill
• OOM
•
• Swap
36

37. Android
•
• (Ubuntu )
• swap
37

38. Android Ubuntu Linux
512MB 1GB 16GB
(Xperia acro) +swap
38

39. •
•
•
• ...
39

40. LowMemoryKiller
•
•
•
40

41. • &
• > > content provider
•
• ?
• /init.rc
41

42. /init.rc ( )
# Define the oom_adj values for the classes of processes that can be
# killed by the kernel. These are used in ActivityManagerService.
setprop ro.FOREGROUND_APP_ADJ 0
setprop ro.VISIBLE_APP_ADJ 1
setprop ro.SECONDARY_SERVER_ADJ 2
setprop ro.BACKUP_APP_ADJ 2
setprop ro.HOME_APP_ADJ 4
setprop ro.HIDDEN_APP_MIN_ADJ 7
setprop ro.CONTENT_PROVIDER_ADJ 14
setprop ro.EMPTY_APP_ADJ 15
# Define the memory thresholds at which the above process classes will
# be killed. These numbers are in pages (4k).
setprop ro.FOREGROUND_APP_MEM 1536
setprop ro.VISIBLE_APP_MEM 2048
setprop ro.SECONDARY_SERVER_MEM 4096
setprop ro.BACKUP_APP_MEM 4096
setprop ro.HOME_APP_MEM 4096
setprop ro.HIDDEN_APP_MEM 5120
setprop ro.CONTENT_PROVIDER_MEM 5632
setprop ro.EMPTY_APP_MEM 6144
42

43. • Linux
• Ubuntu
• Android
• Android Ubuntu
• Android
•
• Binder
•
•
•
43

44. • PC Android Linux
• Android
•
•
44

45. •
45