1. Profiling Memory Usage
of Android Apps
Vivek Jain & Praveen Raj
Geek Night - ThoughtWorks, Pune

2. Memory Management
• No Page Swap
• LRU cache

3. Why Manage Memory?
• LRU app (lowmemkiller)
• Apps retaining large chunks of Memory.
• GC cycle is fast.
• OutOfMemory Exception

4. Garbage Collection
• Type of GC
• Reference counting
• Mark and Sweep
• Mark, Sweep and Compact.
• Android GC is of type. Mark and Sweep(Concurrent)
• Concurrent (Gingerbread and beyond)

5. GC Root
Mark & Sweep

6. Memory Leaks
• GC does not prevent memory leaks
• Reference to un-used objects lead to leaks
• Single reference can prevent large group of objects
from being collected
• Common leaks
• Long lived references to Activity/Context or View
objects

7. Decipher GC messages in
logcat
• Reason
GC_CONCURRENT/GC_FOR_MALLOC/GC_HPROF_DUMP_HEAP/GC_EXPLICIT
• Amount Freed
• Heap Statistics
• External (bitmap, NIO byte buffers) memory statistics
• Pause times
D/dalvikvm( 9050): GC_CONCURRENT freed 2049K, 65% free 3571K/
9991K, external 4703K/5261K, paused 2ms+2ms

8. Heap Dumps
• Generate using:
• DDMS or IDE (Android Studio / Eclipse)
• Calling android.os.debug.dumpHprofData()
• Convert to standard HPROF format(if required):
• hprof-conv heap-original.hprof heap-converted.hprof
• Analyze with tools like Eclipse MAT

9. Demo

10. References and Further
Reading
• Google I/O 2011: Memory management for Android Apps
https://www.youtube.com/watch?v=_CruQY55HOk
• Managing Your App’s Memory
https://developer.android.com/training/articles/memory.html
• Investigating Your RAM Usage
https://developer.android.com/tools/debugging/debugging-memory.html
• Memory Analysis for Android Applications
http://android-developers.blogspot.in/2011/03/memory-analysis-for-
android.html
• Avoiding memory leaks
http://android-developers.blogspot.in/2009/01/avoiding-memory-
leaks.html