Method macServiceLoop

GPRS/MAC.cpp:2390–2470

(pat) This is the main service loop for the entire GPRS subsystem. It processes in time increments of one radio block time unit (4 or 5 GSM frames), about 18 ms. We only use one thread, so no additional locks needed in the entire GPRS code beyond those in the i/o queues. It is attached to the L1 layer below via thread-safe queues in the L1Encoder/L2Decoder classes attached to each PCH (packet phys

// and feed multiple channels simultaneously.
//
void L2MAC::macServiceLoop()
{
	double starttime = 0;	// useless initialization to shut up gcc.
	GPRSLOG(16) << "macServiceLoop:" << LOGVAR(gBSNNext);

	if (GPRSDebug) { starttime = timef(); }
	mac_debug();

	// Step: Each incoming RACH will need a single block assignment.
	// We do this first because if no channels are assigned to GPRS,
	// this will allocate the first GPRS channel as a side effect.
	macServiceRachQ();
	GPRSLOG(16) << "macServiceLoop: after serviceRachQ";

	// Step: Maybe add or free some radio channels.
	macCheckChannels();

	// Step:  Process uplink RadioBlocks from the last timeslot.
	// Do this first because it may change TBF states so that they have
	// downlink messages to send.
	PDCHL1FEC *pdch;
	RN_MAC_FOR_ALL_PDCH(pdch) {	// for all channels assigned to GPRS.
		pdch->debug_test();
		while (RLCRawBlock *src = pdch->uplink()->mchUplinkData.readNoBlock()) {
			processUplinkBlock(pdch,src);
			delete src;
		}
	}

	GPRSLOG(16) << "macServiceLoop: after uplink service";

	// Step:  Service unattached TBFs.  (An attached TBF has resources
	// assigned to its MS. Attached TBFs are handled by dlService().)
	// This could have been combined in servicing the MS,
	// but efficiency is not an issue and this seems more clear.
	// Be a little careful since we are deleting from the list we are iterating.
	{
		TBF *tbf;
		RN_MAC_FOR_ALL_TBF(tbf) {
			// This call may remove the tbf from the list being iterated:
			tbf->mtServiceUnattached();
		}
	}

	// Step: Service the MSs; they may want to start new TBFs.
	MSInfo *ms;
	RN_MAC_FOR_ALL_MS(ms) {
		ms->msService();
	}
	GPRSLOG(16) << "macServiceLoop: after ms service";

	// Step:  Feed each downlink PDCH with RadioBlocks.
	// As a side effect, this services all the [connected] TBFs in round robin order.
	extDyn.edReset();
	RN_MAC_FOR_ALL_PDCH(pdch) {	// for all channels assigned to GPRS.
		extDyn.edSetCn(pdch->CN());
		pdch->downlink()->dlService();
	}