A small experiment to measure the performance of certain ways of calling functions on Android: direct call, call runnable through Handler, call it via a Service (and sending the result back through broadcast).
I used this tool for the profiling: http://developer.android.com/tools/help/systrace.html
Tests performed:
- direct call of a function in a loop
- Message is posted (delayed with 0 delay) to a Handler. The handleMessage() posts a similar Message to itself
- Start Service with implicit intent, the service runs on an Executor and sends result back with global Broadcast
- Start Service with implicit intent, the service runs on the UI thread and sends result back with global Broadcast
- Start Service with explicit intent, the service runs on the UI thread and sends result back with LocalBroadcaster (v4 support lib)
The results (cascading 1000 times):
| test name | Nexus 7 | Samsung Galaxy S3 (average) |
|---|---|---|
| direct call | 52 ms | 30 ms |
| post to handler | 166 ms | 87 ms |
| service /w executor and global broadcast | 2366 ms | 2700 ms |
| service ui thread & global broadcast | 2247 ms | 3200 ms |
| service explicit intent & local broadcast | 1150 ms | 1470 ms |
Notes: broadcasting things actually is relatively fast, though you shouldn't use it for real time data (of course). Local broadcasting is twice as fast as global broadcast. However localBroadcaster uses a Handler internally (check source), but it resolves the Intent target. That makes the call 7-17 times slower (compared to sending message to a Handler). So if you know the target, use a handler instead. :-)
You can also check out an example run (Samsung Galaxy S3) in the trace.html