trx_toolkit/transceiver.py: implement the transmit burst queue

In order to reflect the UL/DL delay caused by the premature burst
scheduling (a.k.a. 'fn-advance') in a virtual environment, the
Transceiver implementation now queues all to be transmitted bursts,
so they remain in the queue until the appropriate time of transmission.

The API user is supposed to call recv_data_msg() in order to obtain
a L12TRX message on the TRXD (data) inteface, so it gets queued by
this function.  Then, to ensure the timeous transmission, the user
of this implementation needs to call clck_tick() on each TDMA
frame.  Both functions are thread-safe (queue mutex).

In a multi-trx configuration, the use of queue additionally ensures
proper burst aggregation on multiple TRXD connections, so all L12TRX
messages are guaranteed to be sent in the right order, i.e. with
monolithically-increasing TDMA frame numbers.

Of course, this change increases the overall CPU usage, given that
each transceiver gets its own queue, and we need to serve them all
on every TDMA frame.  According to my measurements, when running
test cases from ttcn3-bts-test, the average load is ~50% higher
than what it used to be.  Still not significantly high, though.

Change-Id: Ie66ef9667dc8d156ad578ce324941a816c07c105
Related: OS#4658, OS#4546

1 files changed, 9 insertions, 3 deletions

diff --git a/src/target/trx_toolkit/fake_trx.py b/src/target/trx_toolkit/fake_trx.py
index 27c2b888..b487a938 100755
--- a/src/target/trx_toolkit/fake_trx.py
+++ b/src/target/trx_toolkit/fake_trx.py
@@ -388,6 +388,8 @@ class Application(ApplicationBase):
 
 		# Init shared clock generator
 		self.clck_gen = CLCKGen([])
+		# This method will be called on each TDMA frame
+		self.clck_gen.clck_handler = self.clck_handler
 
 		# Power measurement emulation
 		# Noise: -120 .. -105
@@ -456,14 +458,18 @@ class Application(ApplicationBase):
 			for trx in self.trx_list.trx_list:
 				# DATA interface
 				if trx.data_if.sock in r_event:
-					msg = trx.recv_data_msg()
-					if msg is not None:
-						self.burst_fwd.forward_msg(trx, msg)
+					trx.recv_data_msg()
 
 				# CTRL interface
 				if trx.ctrl_if.sock in r_event:
 					trx.ctrl_if.handle_rx()
 
+	# This method will be called by the clock thread
+	def clck_handler(self, fn):
+		# We assume that this list is immutable at run-time
+		for trx in self.trx_list.trx_list:
+			trx.clck_tick(self.burst_fwd, fn)
+
 	def shutdown(self):
 		log.info("Shutting down...")