Introduce separate thread to handle gNB TX processing

This commit introduces a separate thread (l1_tx_thread) that processes
gNB DL/TX slots. It receives a message from the ru_thread when a new
slot started, and starts processing.

The DL part of the scheduler is run in the l1_tx_thread.

The reorder thread is removed, as reordering with this scheme is not
necessary anymore.

The main advantage of this version is that the TX can be scheduled
earlier (sl_ahead). Further, there can no longer be race conditions in
the TX path, since the scheduler/L2, TX L1 processing and the RU tx
function are all execute in the same thread (L1_tX_thread).
Co-authored-by: kiran <saikiran@iitj.ac.in>

executables/nr-ru.c

@@ -1234,7 +1234,9 @@ void *ru_thread( void *param ) {
   wait_sync("ru_thread");
 
   processingData_L1_t *syncMsg;
-  notifiedFIFO_elt_t *res;
+  processingData_L1tx_t *syncMsgTx;
+
+  notifiedFIFO_elt_t *res, *resTx = NULL;
 
   if(!emulate_rf) {
     // Start RF device if any
@@ -1299,14 +1301,13 @@ void *ru_thread( void *param ) {
     if (ru->fh_south_in) ru->fh_south_in(ru,&frame,&slot);
     else AssertFatal(1==0, "No fronthaul interface at south port");
 
-
-    if (initial_wait == 1 && proc->frame_rx < 300 && ru->fh_south_in == rx_rf) {
-       if (proc->frame_rx>0 && ((proc->frame_rx % 100) == 0) && proc->tti_rx==0) {
-          LOG_I(PHY,"delay processing to let RX stream settle, frame %d (trials %d)\n",proc->frame_rx,ru->rx_fhaul.trials);
-          print_meas(&ru->rx_fhaul,"rx_fhaul",NULL,NULL);
-          reset_meas(&ru->rx_fhaul);
-       }
-       continue;
+    if (initial_wait == 1 && proc->frame_rx < 300) {
+      if (proc->frame_rx > 0 && ((proc->frame_rx % 100) == 0) && proc->tti_rx == 0) {
+        LOG_I(PHY, "delay processing to let RX stream settle, frame %d (trials %d)\n", proc->frame_rx, ru->rx_fhaul.trials);
+        print_meas(&ru->rx_fhaul, "rx_fhaul", NULL, NULL);
+        reset_meas(&ru->rx_fhaul);
+      }
+      continue;
     }
     if (proc->frame_rx>=300)  {
       initial_wait=0;
@@ -1384,13 +1385,8 @@ void *ru_thread( void *param ) {
     } // end if (slot_type == NR_UPLINK_SLOT || slot_type == NR_MIXED_SLOT) {
 
     // At this point, all information for subframe has been received on FH interface
-    if (!get_softmodem_params()->reorder_thread_disable) {
-      res = pullTpool(&gNB->resp_L1, &gNB->threadPool);
-      if (res == NULL)
-        break; // Tpool has been stopped
-    } else  {
-      res=newNotifiedFIFO_elt(sizeof(processingData_L1_t),0, &gNB->resp_L1,NULL);
-    }
+    res = newNotifiedFIFO_elt(sizeof(processingData_L1_t), 0, &gNB->resp_L1, NULL);
+    resTx = newNotifiedFIFO_elt(sizeof(processingData_L1tx_t), 0, &gNB->L1_tx_out, NULL);
     syncMsg = (processingData_L1_t *)NotifiedFifoData(res);
     syncMsg->gNB = gNB;
     syncMsg->frame_rx = proc->frame_rx;
@@ -1399,10 +1395,15 @@ void *ru_thread( void *param ) {
     syncMsg->slot_tx = proc->tti_tx;
     syncMsg->timestamp_tx = proc->timestamp_tx;
     res->key = proc->tti_rx;
-    if (!get_softmodem_params()->reorder_thread_disable) 
-      pushTpool(&gNB->threadPool, res);
-    else 
-      pushNotifiedFIFO(&gNB->resp_L1, res);
+
+    syncMsgTx = (processingData_L1tx_t *)NotifiedFifoData(resTx);
+    syncMsgTx->gNB = gNB;
+    syncMsgTx->frame = proc->frame_tx;
+    syncMsgTx->slot = proc->tti_tx;
+    syncMsgTx->timestamp_tx = proc->timestamp_tx;
+    resTx->key = proc->tti_tx;
+    pushNotifiedFIFO(&gNB->resp_L1, res);
+    pushNotifiedFIFO(&gNB->L1_tx_out, resTx);
   }
 
   printf( "Exiting ru_thread \n");

openair1/PHY/NR_TRANSPORT/nr_prach.c

@@ -76,8 +76,7 @@ void nr_fill_prach(PHY_VARS_gNB *gNB,
 		   nfapi_nr_prach_pdu_t *prach_pdu) {
 
   int prach_id = find_nr_prach(gNB,SFN,Slot,SEARCH_EXIST_OR_FREE);
-  AssertFatal( ((prach_id>=0) && (prach_id<NUMBER_OF_NR_PRACH_MAX)) || (prach_id < 0),
-              "illegal or no prach_id found!!! prach_id %d\n",prach_id);
+  AssertFatal(((prach_id >= 0) && (prach_id < NUMBER_OF_NR_PRACH_MAX)), "illegal or no prach_id found!!! prach_id %d\n", prach_id);
 
   gNB->prach_vars.list[prach_id].frame=SFN;
   gNB->prach_vars.list[prach_id].slot=Slot;

openair1/PHY/defs_gNB.h

@@ -639,8 +639,6 @@ typedef struct PHY_VARS_gNB_s {
 
   int ldpc_offload_flag;
 
-  int reorder_thread_disable;
-
   int max_ldpc_iterations;
   /// indicate the channel estimation technique in time domain
   int chest_time;

openair1/SCHED_NR/fapi_nr_l1.c

@@ -160,14 +160,7 @@ void nr_schedule_response(NR_Sched_Rsp_t *Sched_INFO)
     if (slot_type == NR_DOWNLINK_SLOT || slot_type == NR_MIXED_SLOT) {
       notifiedFIFO_elt_t *res=NULL;
       processingData_L1tx_t *msgTx=NULL;
-      if (!gNB->reorder_thread_disable) {
-        res = pullNotifiedFIFO(&gNB->L1_tx_free);
-        if (res == NULL)
-          return; // Tpool has been stopped, nothing to process
-        msgTx = (processingData_L1tx_t *)NotifiedFifoData(res);
-      } else {
-        msgTx = gNB->msgDataTx; //newNotifiedFIFO_elt(sizeof(processingData_L1tx_t),0, &gNB->L1_tx_out,NULL);
-      }
+      msgTx = gNB->msgDataTx; // newNotifiedFIFO_elt(sizeof(processingData_L1tx_t),0, &gNB->L1_tx_out,NULL);
       /*const time_stats_t ts = exec_time_stats_NotifiedFIFO(res);
       merge_meas(&gNB->phy_proc_tx, &ts);
 */
@@ -222,8 +215,6 @@ void nr_schedule_response(NR_Sched_Rsp_t *Sched_INFO)
        * released only when both threads are done with it.
        */
       inc_ref_sched_response(Sched_INFO->sched_response_id);
-      if (!gNB->reorder_thread_disable)
-	pushNotifiedFIFO(&gNB->L1_tx_filled,res);
     }
 
     for (int i = 0; i < number_ul_tti_pdu; i++) {
@@ -267,7 +258,9 @@ void nr_schedule_response(NR_Sched_Rsp_t *Sched_INFO)
   }
 
   /* this thread is done with the sched_info, decrease the reference counter */
-  deref_sched_response(Sched_INFO->sched_response_id);
-
+  if (slot_type == NR_DOWNLINK_SLOT || slot_type == NR_MIXED_SLOT) {
+    LOG_D(NR_PHY, "Calling dref_sched_response for id %d in %d.%d (sched_response)\n", Sched_INFO->sched_response_id, frame, slot);
+    deref_sched_response(Sched_INFO->sched_response_id);
+  }
   stop_meas(&gNB->schedule_response_stats);
 }

openair1/SCHED_NR/phy_procedures_nr_gNB.c

@@ -410,9 +410,6 @@ static int nr_ulsch_procedures(PHY_VARS_gNB *gNB, int frame_rx, int slot_rx, int
 
 void nr_fill_indication(PHY_VARS_gNB *gNB, int frame, int slot_rx, int ULSCH_id, uint8_t harq_pid, uint8_t crc_flag, int dtx_flag)
 {
-  if (!get_softmodem_params()->reorder_thread_disable) 
-    pthread_mutex_lock(&gNB->UL_INFO_mutex);
-
   NR_gNB_ULSCH_t *ulsch = &gNB->ulsch[ULSCH_id];
   NR_UL_gNB_HARQ_t *harq_process = ulsch->harq_process;
   NR_gNB_PHY_STATS_t *stats = get_phy_stats(gNB, ulsch->rnti);
@@ -557,9 +554,6 @@ void nr_fill_indication(PHY_VARS_gNB *gNB, int frame, int slot_rx, int ULSCH_id,
   }
 
   gNB->UL_INFO.rx_ind.number_of_pdus++;
-
-  if (!get_softmodem_params()->reorder_thread_disable) 
-    pthread_mutex_unlock(&gNB->UL_INFO_mutex);
 }
 
 // Function to fill UL RB mask to be used for N0 measurements

openair1/SIMULATION/NR_PHY/dlsim.c

@@ -895,6 +895,7 @@ int main(int argc, char **argv)
   msgDataTx->slot = slot;
   msgDataTx->frame = frame;
   memset(msgDataTx->ssb, 0, 64*sizeof(NR_gNB_SSB_t));
+  gNB->msgDataTx = msgDataTx;
 
   // Buffers to store internal memory of slot process
   int rx_size = (((14 * frame_parms->N_RB_DL * 12 * sizeof(int32_t)) + 15) >> 4) << 4;

openair1/SIMULATION/NR_PHY/ulsim.c

@@ -563,6 +563,7 @@ int main(int argc, char *argv[])
   notifiedFIFO_elt_t *msgL1Tx = newNotifiedFIFO_elt(sizeof(processingData_L1tx_t), 0, &gNB->L1_tx_free, NULL);
   processingData_L1tx_t *msgDataTx = (processingData_L1tx_t *)NotifiedFifoData(msgL1Tx);
   msgDataTx->slot = -1;
+  gNB->msgDataTx = msgDataTx;
   //gNB_config = &gNB->gNB_config;
 
   //memset((void *)&gNB->UL_INFO,0,sizeof(gNB->UL_INFO));

openair2/NR_PHY_INTERFACE/NR_IF_Module.c

@@ -486,21 +486,6 @@ void NR_UL_indication(NR_UL_IND_t *UL_info) {
   if (get_softmodem_params()->emulate_l1) {
     free_unqueued_nfapi_indications(rach_ind, uci_ind, rx_ind, crc_ind);
   }
-
-  if (NFAPI_MODE != NFAPI_MODE_PNF) {
-    gNB_MAC_INST     *mac        = RC.nrmac[module_id];
-
-    NR_IF_Module_t *ifi = nr_if_inst[module_id];
-    ifi->current_frame    = UL_info->frame;
-    ifi->current_slot = UL_info->slot;
-
-    nfapi_nr_config_request_scf_t *cfg = &mac->config[CC_id];
-    int spf = get_spf(cfg);
-    int CC_id = 0;
-    int frame_tx = UL_info->frame + ((UL_info->slot > (spf - 1 - ifi->sl_ahead)) ? 1 : 0);
-    int slot_tx = (UL_info->slot + ifi->sl_ahead) % spf;
-    ifi->NR_slot_indication(module_id, CC_id, frame_tx, slot_tx);
-  }
 }
 
 NR_IF_Module_t *NR_IF_Module_init(int Mod_id) {