I created an architecture with a process A communicating to another process B through IPC.
A runs a sticky service. B runs a sticky service.
This A service binds to the B service.
When bind succeeds,
- for requests from A to B, A creates :
mRequestMessenger = new Messenger(service); //service comes from onServiceConnected(..., IBinder service)
- for answers from B to A, A creates :
//create the handler thread, start it
mResponseHandlerThread = new HandlerThread(mModuleName);
mResponseHandlerThread.start();
//Set thread as looper of ResponseHandler
mResponseHandler = new ResponseHandler(mResponseHandlerThread.getLooper()); //ResponseHandler is a Handler
//Set ResponseMessenger into messenger to receive callback
mResponseMessenger = new Messenger(mResponseHandler);
When A receives the responses from B, it is treated by first logging the received android.os.Message object instance.
This message has the field "when" which shows the delay between message sent from B and message received in A.
For most of the cases, the value of when is around 0ms or -1ms (negative value due to computation : createdtime - now)
For really rare cases, the messages seem stuck until something unlocks the situation.
Logs shows :
when=-1h49m55s146ms
when=-1h49m53s904ms
when=-1h49m54s502ms
.... until all "stuck" messages are well received.
Additionnally, when there are too many stuck messages, it seems that some of them are lost, with a limit of 875 messages.
I can't figure out what could explain this behavior.
