Android Platform Debugging and Development at ELCE 2013
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This document provides an overview of debugging and development tools and techniques for the Android platform. It discusses the architecture basics, development environment setup in Eclipse, tools for observing and monitoring including logcat, dumpsys and ftrace. It also covers interfacing with the framework, symbolic debugging with DDMS and gdb, and detailed dynamic data collection using logging and profiling tools like perf.
![11
/frameworks/base/services/java/...
/frameworks/base/services/jni/
/hardware/libhardware/
/device/[MANUF.]/[DEVICE]
/sdk/emulator/
Kernel or module
/frameworks/base/core/...
AOSP-provided
ASL
Manuf.-provided
Manuf. license
Manuf.-provided
GPL-license](https://image.slidesharecdn.com/android-platform-debug-dev-clean-131030-140516121934-phpapp02/85/Android-Platform-Debugging-and-Development-at-ELCE-2013-11-320.jpg)
![19
●
Set up basic classpath file:
[aosp]$ cp development/ide/eclipse/.classpath .
●
Adjust eclipse.ini
● On my ADT bundle, it's:
– adt-bundle-linux-x86_64-20130917/eclipse/eclipse.ini
●
Change this:
-XX:MaxPermSize=256m
-Xms40m
-Xmx768m
●
To this:
-XX:MaxPermSize=256m
-Xms128m
-Xmx768m](https://image.slidesharecdn.com/android-platform-debug-dev-clean-131030-140516121934-phpapp02/85/Android-Platform-Debugging-and-Development-at-ELCE-2013-19-320.jpg)
![45
6.8. How to know what's the
address of the library
# cat /proc/[system_sever PID]/maps | grep android_servers
4aff50004b007000 rxp 00000000 1f:00 519 /system/lib/libandroid_servers.so
4b0070004b008000 rp 00011000 1f:00 519 /system/lib/libandroid_servers.so
4b0080004b009000 rwp 00012000 1f:00 519 /system/lib/libandroid_servers.so
# cat /proc/[system_sever PID]/maps | grep libc.so
400270004006c000 rxp 00000000 1f:00 601 /system/lib/libc.so
4006d0004006f000 rp 00045000 1f:00 601 /system/lib/libc.so
4006f00040071000 rwp 00047000 1f:00 601 /system/lib/libc.so
$ objdump h out/target/product/generic/system/lib/libandroid_servers.so | grep text
7 .text 00006ae8 000078b8 000078b8 000078b8 2**3
$ objdump h out/target/product/generic/system/lib/libc.so | grep text
7 .text 0002f080 0000c9b8 0000c9b8 0000c9b8 2**3
4aff5000 + 000078b8 = 0x4AFFC8B8
40027000 + 0000c9b8 = 0x400339B8
http://linux-mobile-hacker.blogspot.co.uk/2008/02/debug-shared-library-with-gdbserver.html](https://image.slidesharecdn.com/android-platform-debug-dev-clean-131030-140516121934-phpapp02/85/Android-Platform-Debugging-and-Development-at-ELCE-2013-45-320.jpg)
![53
# atrace help
usage: atrace [options] [categories...]
options include:
a appname enable applevel tracing for a comma separated list of
cmdlines
b N use a trace buffer size of N KB
c trace into a circular buffer
k fname,... trace the listed kernel functions
n ignore signals
s N sleep for N seconds before tracing [default 0]
t N trace for N seconds [defualt 5]
z compress the trace dump
async_start start circular trace and return immediatly
async_dump dump the current contents of circular trace buffer
async_stop stop tracing and dump the current contents of circular
trace buffer
list_categories
list the available tracing categories](https://image.slidesharecdn.com/android-platform-debug-dev-clean-131030-140516121934-phpapp02/85/Android-Platform-Debugging-and-Development-at-ELCE-2013-53-320.jpg)
Android Platform Debugging and Development at ELCE 2013
- 1. 1 Android Platform Debugging and Development Embedded Linux Conference Europe 2013 Karim Yaghmour @karimyaghmour karim.yaghmour@opersys.com
- 2. 2 These slides are made available to you under a Creative Commons Share- Alike 3.0 license. The full terms of this license are here: https://creativecommons.org/licenses/by-sa/3.0/ Attribution requirements and misc., PLEASE READ: ● This slide must remain as-is in this specific location (slide #2), everything else you are free to change; including the logo :-) ● Use of figures in other documents must feature the below “Originals at” URL immediately under that figure and the below copyright notice where appropriate. ● You are free to fill in the “Delivered and/or customized by” space on the right as you see fit. ● You are FORBIDEN from using the default “About” slide as-is or any of its contents. ● You are FORBIDEN from using any content provided by 3rd parties without the EXPLICIT consent from those parties. (C) Copyright 2013, Opersys inc. These slides created by: Karim Yaghmour Originals at: www.opersys.com/community/docs Delivered and/or customized by
- 3. 3 About ● Author of: ● Introduced Linux Trace Toolkit in 1999 ● Originated Adeos and relayfs (kernel/relay.c) ● Training, Custom Dev, Consulting, ...
- 4. 4 Agenda 1. Architecture Basics 2. Development environment 3. Observing and monitoring 4. Interfacing with the framework 5. Working with the AOSP sources 6. Symbolic debugging 7. Detailed dynamic data collection 8. Benchmarking 9. Summing up
- 5. 5 1. Architecture Basics ● Hardware used to run Android ● AOSP ● Binder ● System Services ● HAL
- 6. 6
- 7. 7
- 8. 8
- 9. 9
- 10. 10
- 11. 11 /frameworks/base/services/java/... /frameworks/base/services/jni/ /hardware/libhardware/ /device/[MANUF.]/[DEVICE] /sdk/emulator/ Kernel or module /frameworks/base/core/... AOSP-provided ASL Manuf.-provided Manuf. license Manuf.-provided GPL-license
- 12. 12 2. Development Environment ● Host / Target setup ● IDE / Editor ● Eclipse setup
- 13. 13 2.1. Host / Target setup
- 14. 14
- 15. 15 2.2. IDE / Editor Logos belong to their respective owners. This slide isn't CC-BY-SA.
- 16. 16 What if ... ?
- 17. 17 2.3. Eclipse Setup ● Preparation ● Project importing ● AOSP fixups ● Browsing the sources
- 18. 18 2.3.1. Preparation ● AOSP Basics: ● Get AOSP ... from Google or otherwise ● Extract if needed ● Configure, build, etc. ● Eclipse / ADT: ● Get ADT bundle from developer.android.com ● Extract ● Start and update and if needed
- 19. 19 ● Set up basic classpath file: [aosp]$ cp development/ide/eclipse/.classpath . ● Adjust eclipse.ini ● On my ADT bundle, it's: – adt-bundle-linux-x86_64-20130917/eclipse/eclipse.ini ● Change this: -XX:MaxPermSize=256m -Xms40m -Xmx768m ● To this: -XX:MaxPermSize=256m -Xms128m -Xmx768m
- 20. 20 2.3.2. Project importing ● Start Eclipse ● Create new "Java project" ● Project name = your AOSP name ● Deselect "Use default location" ● Location = path to your AOSP ● Click "Next" ● Wait a little bit ... ● Click "Finish" ● Wait for it to build your project ● ... it likely will fail ...
- 21. 21 2.3.3. AOSP fixups ● Need to fix AOSP classpath file and sources ● Assuming 4.3 here ● Add this: <classpathentry kind="src" path="frameworks/opt/timezonepicker/src"/> <classpathentry kind="src" path="frameworks/opt/colorpicker/src"/> <classpathentry kind="src" path="frameworks/opt/datetimepicker/src"/> <classpathentry kind="src" path="frameworks/support/v8/renderscript/java/src"/> ● Remove this: <classpathentry kind="src" path="frameworks/support/renderscript/v8/java/src"/>
- 22. 22 ● Comment out a couple of things: <! Redefines android.util.pools which confuses Eclipse <classpathentry kind="src" path="packages/apps/Gallery2/src"/> <classpathentry kind="src" path="packages/apps/Gallery2/src_pd"/> <classpathentry kind="src" path="packages/apps/Gallery2/gallerycommon/src"/> > <! <classpathentry kind="src" path="packages/apps/Nfc/src"/> <classpathentry kind="src" path="packages/apps/Nfc/nci/src"/> > <! <classpathentry kind="src" path="frameworks/ex/carousel/java"/> >
- 23. 23 ● Manually build the following (cd to and "mm") -- or remove from .classpath: packages/apps/Stk packages/screensavers/WevView development/samples/ApiDemos development/samples/HelloActivity development/samples/Home development/samples/LunarLander development/samples/NotePad development/samples/RSSReader development/samples/SkeletonApp development/samples/Snake
- 24. 24 ● Edit packages/apps/Launcher/src/com/android/launcher 2/DragLayer.java and modify: private boolean isLayoutRtl() { ● to public boolean isLayoutRtl() { ● Now: right-click on project and select "Refresh" ● It might still show "x" on some parts until it's done rebuilding the project
- 25. 25 2.3.4. Browsing the sources ● Mouse-over object type to be taken to declaration ● Browse classes through “Outline” ● Browse Call Hierarchy ● View recently viewed files (Ctrl-e) ● Many other shortcuts, see: ● http://source.android.com/source/using-eclipse.html ● Issues: ● Can't compile with Eclipse ... still need “make” ● For Java only
- 26. 26 3. Observing and Monitoring ● Native ● Framework ● Overall
- 27. 27 3.1. Native ● schedtop ● librank ● procmem ● procrank ● showmap ● latencytop
- 28. 28 3.2. Framework ● dumpsys ● service
- 29. 29 3.3 Overall ● logcat ● dumpstate / bugreport ● watchprop / getprop
- 30. 30
- 31. 31 4. Interfacing With the Framework ● start / stop ● service call ● am ● pm ● wm ● svc ● monkey ● setprop
- 32. 32 5. Working with the AOSP Sources ● You really need to check build/envsetup.sh ● Some tricks: ● godir ● croot ● mm ● m ● jgrep ● cgrep ● resgrep ● It takes time to wrap your head around the tree
- 33. 33 6. Symbolic Debugging - basics
- 34. 34 6.1. DDMS / Eclipse integration ● Start DDMS: ● The one from the AOSP's command-line ● Not the one from Eclipse (“connection refuse”) ● It takes some time to load -- a few minutes ● Each process has a separate host-side socket ● Select the process you want to debug: ● It'll get port 8700
- 35. 35 ● Go to Eclipse: ● Run->Debug Configurations->Remote Java Application ● Connection Type: "Standard (Socket Attach)" ● Host: localhost ● Port: 8700
- 36. 36 6.2. Starting debug w/ Eclipse ● Order is finicky: ● Start your device or emulator ● Start command-line DDMS before Eclipse otherwise you'll get this in logcat: "I/jdwp ( 411): Ignoring second debugger -- accepting and dropping" ● Start Eclipse ● Eclipse will complain that there's already a DDMS running. Ignore that.
- 37. 37
- 38. 38 6.3. Debugging ● Select the process you want to debug in DDMS ● Go into Eclipse and click on the debug configuration you created earlier ● Check that the little green bug is beside your process in DDMS ● Again, things can look like they're freezing, this is "normal" for Eclipse ... ● Wait for Eclipse to show your Dalvik process in the "Debug" *window* in the "Debug" *view* -- all threads should show
- 39. 39
- 40. 40 6.4. Debugging multiple processes ● In the debug *view* of eclipse, click on "Debug" for every time you change the process in DDMS ● Wait for that process' threads to load in the debug view ● Once threads are loaded, you can actually start debugging
- 41. 41 6.5. gdbserver - target side ● First, you'll need to make sure your C code is compiled appropriately. Add this to Android.mk: LOCAL_CFLAGS += -ggdb LOCAL_STRIP_MODULE = false ● Attaching to running process # gdbserver attach locahost:2345 30 ● Start app for debugging with gdbserver prepended # gdbserver localhost:2345 service list ● Forward the port on the host: $ adb forward tcp:2345 tcp:2345
- 42. 42 6.6. gdb - host side ● Load file **FIRST** and then attach on host side $ prebuilts/gcc/linuxx86/arm/armeabi4.7/bin/armeabigdb GNU gdb (GDB) 7.3.1gg2 Copyright (C) 2011 Free Software Foundation, Inc. ... (gdb) file out/target/product/generic/system/bin/service (gdb) target remote localhost:2345 (gdb) b main Cannot access memory at address 0x0 Breakpoint 1 at 0x2a00146c: file frameworks/native/cmds/service/service.cpp, line 59. (gdb) cont Continuing. warning: Could not load shared library symbols for 11 libraries, e.g. /system/bin/linker. ... Breakpoint 1, main (argc=2, argv=0xbe882b74) at frameworks/native/cmds/service/service.cpp:59 59 { (gdb) n 60 sp<IServiceManager> sm = defaultServiceManager(); (gdb) n 59 { (gdb) n 60 sp<IServiceManager> sm = defaultServiceManager(); (gdb) n 61 fflush(stdout);
- 43. 43 6.7. Multi-threaded = #FAIL $ prebuilts/gcc/linuxx86/arm/armeabi4.7/bin/armeabigdb GNU gdb (GDB) 7.3.1gg2 ... (gdb) addsymbolfile out/target/product/generic/system/lib/libandroid_servers.so 0x4AFFC8B8 add symbol table from file "out/target/product/generic/system/lib/libandroid_servers.so" at .text_addr = 0x4affc8b8 (y or n) y (gdb) addsymbolfile out/target/product/generic/system/lib/libc.so 0x400339B8 add symbol table from file "out/target/product/generic/system/lib/libc.so" at .text_addr = 0x400339b8 (y or n) y (gdb) target remote localhost:2345 Remote debugging using localhost:2345 __ioctl () at bionic/libc/archarm/syscalls/__ioctl.S:10 10 mov r7, ip (gdb) b com_android_server_power_PowerManagerService.cpp:162 Breakpoint 1 at 0x4b000a34: file frameworks/base/services/jni/com_android_server_power_PowerManagerService.cpp, line 162. (gdb) cont Continuing. Program terminated with signal SIGTRAP, Trace/breakpoint trap. The program no longer exists. ...
- 44. 44 ● Even if you try attaching to the specific thread in the system server running the system service you're trying to instrument, you'll get the same issue. ● Probably requires rebuilding gdbserver with thread support: ● https://sourceware.org/ml/gdb/2009-01/msg00084.html ● http://code.google.com/p/android/issues/detail?id=9713 ● Issues seems to be solved in NDK but not in gdbserver in AOSP: ● http://comments.gmane.org/gmane.comp.handhelds.android.ndk/12122
- 45. 45 6.8. How to know what's the address of the library # cat /proc/[system_sever PID]/maps | grep android_servers 4aff50004b007000 rxp 00000000 1f:00 519 /system/lib/libandroid_servers.so 4b0070004b008000 rp 00011000 1f:00 519 /system/lib/libandroid_servers.so 4b0080004b009000 rwp 00012000 1f:00 519 /system/lib/libandroid_servers.so # cat /proc/[system_sever PID]/maps | grep libc.so 400270004006c000 rxp 00000000 1f:00 601 /system/lib/libc.so 4006d0004006f000 rp 00045000 1f:00 601 /system/lib/libc.so 4006f00040071000 rwp 00047000 1f:00 601 /system/lib/libc.so $ objdump h out/target/product/generic/system/lib/libandroid_servers.so | grep text 7 .text 00006ae8 000078b8 000078b8 000078b8 2**3 $ objdump h out/target/product/generic/system/lib/libc.so | grep text 7 .text 0002f080 0000c9b8 0000c9b8 0000c9b8 2**3 4aff5000 + 000078b8 = 0x4AFFC8B8 40027000 + 0000c9b8 = 0x400339B8 http://linux-mobile-hacker.blogspot.co.uk/2008/02/debug-shared-library-with-gdbserver.html
- 46. 46 6.9. JTAG ● Requires hardware device ● Sometimes interfaces with gdb ● Not Android specific ● Some allow transparent kernel/user-space debug ● Don't know of any that go all the way up to Dalvik
- 47. 47 7. Detailed Dynamic Data Collection ● Logging ● ftrace ● perf
- 48. 48 7.1. Logging ● logcat is the most rapid/consistent way to observe dynamic behavior. ● Trivial to add instrumentation points ● It just works ...
- 49. 49 7.2. ftrace ● With 4.1, Google introduced systrace/atrace ● systrace is a Python script running on host side ● atrace is native Android binary ● systrace calls atrace via ADB ● atrace uses ftrace to capture kernel events ● Stack instrumented to feed events to ftrace ● Google's doc: ● https://developer.android.com/tools/help/systrace.html ● https://developer.android.com/tools/debugging/systrace.html
- 50. 50
- 51. 51 ... trouble is ... ● I can't get it to work !*!@#$&!#*$! ● Default goldfish kernel doesn't have ftrace ● Able to build ftrace-enabled kernel for goldfish ● Can trace that system ... so long as I don't use atrace/systrace ... WTF1 ? ● Not all Android kernels have ftrace enabled ● Generates HTML file that can only be read by Chrome ... it doesn't work in Firefox. NIH? 1: The AOSP sources define WTF as “What a Terrible Failure”. We trust they've done their research.
- 52. 52 ... still ... ● Have a look at these files: ● /external/chromium-trace/systrace.py ● /frameworks/native/cmds/atrace ● /frameworks/base/core/java/android/os/Trace.java ● /erameworks/native/include/utils/Trace.h ● /system/core/include/cutils/trace.h ● /frameworks/native/libs/utils/Trace.cpp ● Look for: ● ATRACE* in c/cpp files ● Trace.traceBegin()/trace.traceEnd() in Java files
- 55. 55 7.3. perf on Android on ARM
- 57. 57 0xbench AnTuTu Passmark Vellamo Geekbench2 SunSpider GLBenchmakr Quadrant Standard Edition Linpack Neocore 3DMark Epic Citadel Androbench CF-bench SD Tools RL Benchmark: SQL Benchmark & Tunning A1 SD Bench Quick Benchmark Lite 3DRating benchmark Smartbench 2011 NenaMark Rightware Browsermark An3DBenchXL CaffeineMark NBench Methanol AndEBench SmartBench 2012 RealPi
- 58. 58 ● Works relatively well: ● logcat ● Eclipse / DDMS ● Framework tools ● Works ok: ● gdb/gdbserver ● native tools ● ftrace ● Doesn't work (for me): ● systrace/atrace ● perf 9. Summing Up
- 59. 59 10. Loose ends ● strace ● debuggerd ● tombstones ● anr traces