Sunday, February 8, 2015





DEBUGGING

Android Logging

- user space logging
adb logcat  > logcat.txt

To enable meta data option with logcat , -v option can be used which includes :
ex- adb logcat -v threadtime > logcat.txt
brief — Display priority/tag and PID of originating process (the default format).
process — Display PID only.
tag — Display the priority/tag only.
thread — Display process:thread and priority/tag only.
raw — Display the raw log message, with no other metadata fields.
time — Display the date, invocation time, priority/tag, and PID of the originating process.
long — Display all metadata fields and separate messages with a blank lines.
alternative logging using -b option 

ex - adb logcat -b events > events.txt
radio — View the buffer that contains radio/telephony related messages.
events — View the buffer containing events-related messages.
main — View the main log buffer (default)

- kernel space logging

adb shell dmesg

or ,
adb root
adb shell cat /proc/kmsg > kernel.txt


Process CPU utilization :

adb shell top 

with -m option , the number of process can be selected for which % is needed.

ex  - adb shell top -m 5

Memory Info

adb shell cat proc/meminfo



procrank shows you a quick summary of process memory utilization. By default, it shows Vss, Rss, Pss and Uss, and sorts by Vss. However, you can control the sorting order.
procrank source is included in system/extras/procrank, and the binary is located in /system/xbin on an android device.
  • Vss = virtual set size
  • Rss = resident set size
  • Pss = proportional set size
  • Uss = unique set size
In general, the two numbers you want to watch are the Pss and Uss (Vss and Rss are generally worthless, because they don't accurately reflect a process's usage of pages shared with other processes.)
  • Uss is the set of pages that are unique to a process. This is the amount of memory that would be freed if the application was terminated right now.
  • Pss is the amount of memory shared with other processes, accounted in a way that the amount is divided evenly between the processes that share it. This is memory that would not be released if the process was terminated, but is indicative of the amount that this process is "contributing"
to the overall memory load.
You can also use procrank to view the working set size of each process, and to reset the working set size counters.
Here is procrank's usage:
# procrank -h
Usage: procrank [ -W ] [ -v | -r | -p | -u | -h ]
    -v  Sort by VSS.
    -r  Sort by RSS.
    -p  Sort by PSS.
    -u  Sort by USS.
        (Default sort order is PSS.)
    -R  Reverse sort order (default is descending).
    -w  Display statistics for working set only.
    -W  Reset working set of all processes.
    -h  Display this help screen.
And here is some sample output:
# procrank
  PID      Vss      Rss      Pss      Uss  cmdline
 1217   36848K   35648K   17983K   13956K  system_server
 1276   32200K   32200K   14048K   10116K  android.process.acore
 1189   26920K   26920K    9293K    5500K  zygote
 1321   20328K   20328K    4743K    2344K  android.process.media
 1356   20360K   20360K    4621K    2148K  com.android.email
 1303   20184K   20184K    4381K    1724K  com.android.settings
 1271   19888K   19888K    4297K    1764K  com.android.inputmethod.latin
 1332   19560K   19560K    3993K    1620K  com.android.alarmclock
 1187    5068K    5068K    2119K    1476K  /system/bin/mediaserver
 1384     436K     436K     248K     236K  procrank
    1     212K     212K     200K     200K  /init
  753     572K     572K     171K     136K  /system/bin/rild
  748     340K     340K     163K     152K  /system/bin/sh
  751     388K     388K     156K     140K  /system/bin/vold
 1215     148K     148K     136K     136K  /sbin/adbd
  757     352K     352K     117K      92K  /system/bin/dbus-daemon
  760     404K     404K     104K      80K  /system/bin/keystore
  759     312K     312K     102K      88K  /system/bin/installd
  749     288K     288K      96K      84K  /system/bin/servicemanager
  752     244K     244K      71K      60K  /system/bin/debuggerd


How to debug native process memory allocations

 adb root

 adb shell setprop libc.debug.malloc 1

adb shell stop

adb shell start

Supported values for libc.debug.malloc (debug level values) are:
  • 1 - perform leak detection
  • 5 - fill allocated memory to detect overruns
  • 10 - fill memory and add sentinels to detect overruns
  • 20 - use special instrumented malloc/free routines for the emulator


loglevel

loglevel — Set the default console log level.
The console log level can also be changed by the klogd program, or by writing the specified level to the /proc/sys/kernel/printk file.

The kernel log levels are:
0 (KERN_EMERG)
The system is unusable.
1 (KERN_ALERT)
Actions that must be taken care of immediately.
2 (KERN_CRIT)
Critical conditions.
3 (KERN_ERR)
Non-critical error conditions.
4 (KERN_WARNING)
Warning conditions that should be taken care of.
5 (KERN_NOTICE)
Normal, but significant events.
6 (KERN_INFO)
Informational messages that require no action.
7 (KERN_DEBUG)
Kernel debugging messages, output by the kernel if the developer enabled debugging at compile time.

log_buf_len

log_buf_len — Set the size of the kernel log buffer.
 Set the size of the kernel's internal log buffer. n must be a power of 2, if not, it will be rounded up to be a power of two.
 
  

GDB Debugging :   


 copy  <build_path>obj/EXECUTABLES/gdbserver_intermediates/gdbserver. to the device

 host:> adb forward tcp:5039 tcp:5039
host:> adb shell
<device># gdbserver :5039 </path/to/executable> [<cmd line params>]
host:> cd </path/to/unstripped/executable>
host:> arm-eabi-gdb
  (gdb) file <executable>
  (gdb) set solib-absolute-prefix <android product out>/symbols (optional - may not be required)
  (gdb) set solib-search-path <android product out>/system/lib  (optional - may not be required)
  (gdb) target remote :5039
  (gdb) shared (optional - may not be required)
  (gdb) b main
  (gdb) cont

or for remote

1) adb forward tcp:5039 tcp:5039
2) adb shell ps mediaserver
3) adb shell gdbserver :5039 --attach <pid>
4) gdbclient mediaserver :5039
5) (gdb) b <filename>:<line_num>
6) (gdb) cont

for core dump analysis :

$arm-linux-androideabi-gdb symbols/system/bin/app_process

(gdb) set solib-absolute-prefix ./symbols
(gdb) set solib-search-path ./symbols/system/lib:./symbols/system/lib/egl:./symbols/system/lib/hw:
(gdb) core <core_file>

(gdb) backtrace full  or bt
(gdb) info register
(gdb) disassemble <addr>
 


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