Add more RLC stats and correct RLC stats

- Add GOL-delay and AVG-soujour
- Correct the types of/measurement the tx/rxsdu_bytes and tx/rxsdu_occ_bytes
- Update txsdu_avg_time_to_tx value only when measurements activated
Co-authored-by: Teodora Vladic <teodora.vladic@openairinterface.org>

openair2/LAYER2/nr_rlc/nr_rlc_entity.c

@@ -36,10 +36,36 @@ static void nr_rlc_entity_get_stats(
     nr_rlc_statistics_t *out)
 {
 // printf("Stats from the RLC entity asked\n");
+  uint64_t time_now = time_average_now();
   *out = entity->stats;
+
+  // Get the correct HOL RLC-SDU
+  nr_rlc_sdu_segment_t* sdu;
+  if (entity->stats.mode == NR_RLC_AM) {
+    nr_rlc_entity_am_t* am_entity = (nr_rlc_entity_am_t *) entity;
+    if (am_entity->retransmit_list != NULL) {
+      sdu = am_entity->retransmit_list;
+    } else {
+      sdu = am_entity->tx_list;
+    }
+  } else if (entity->stats.mode == NR_RLC_UM) {
+    nr_rlc_entity_um_t* um_entity = (nr_rlc_entity_um_t *) entity;
+    sdu = um_entity->tx_list;
+  } else {
+    nr_rlc_entity_tm_t* tm_entity = (nr_rlc_entity_tm_t *) entity;
+    sdu = tm_entity->tx_list;
+  }
+
+  // Compute HOL waittime, make sure that segmented packets don't have 'zero' time-of-arrival
+  if (sdu != NULL) {
+    out->txsdu_wt_us = time_now - sdu->sdu->time_of_arrival;
+  } else {
+    // No HOL packets --> wait-time == 0
+    out->txsdu_wt_us = 0;
+  }
+
   if (entity->avg_time_is_on)
-    out->txsdu_avg_time_to_tx = time_average_get_average(entity->txsdu_avg_time_to_tx,
-                                    time_average_now());
+    out->txsdu_avg_time_to_tx = time_average_get_average(entity->txsdu_avg_time_to_tx, time_now);
   else
     out->txsdu_avg_time_to_tx = 0;
 }
@@ -112,8 +138,11 @@ nr_rlc_entity_t *new_nr_rlc_entity_am(
 
   ret->common.stats.mode = NR_RLC_AM;
 
+  ret->common.stats.rxsdu_bytes = 0;  // init default arrivals (SDU) counter
+  ret->common.stats.txsdu_bytes = 0;  // init default transmits (SDU) counter
+
   /* let's take average over the last 100 milliseconds
-   * initial_size of 1024 is arbitrary
+   * initial_size of 1024 (packets) is arbitrary
    */
   ret->common.txsdu_avg_time_to_tx = time_average_new(100 * 1000, 1024);
 

openair2/LAYER2/nr_rlc/nr_rlc_entity.h

@@ -41,8 +41,7 @@ typedef struct {
   /* TX */
   uint32_t txpdu_pkts;         /* aggregated number of transmitted RLC PDUs */
   uint32_t txpdu_bytes;        /* aggregated amount of transmitted bytes in RLC PDUs */
-  /* TODO? */
-  uint32_t txpdu_wt_ms;      /* aggregated head-of-line tx packet waiting time to be transmitted (i.e. send to the MAC layer) */
+  uint32_t txpdu_wt_ms;        /* TODO: aggregated head-of-line tx packet waiting time to be transmitted (i.e. send to the MAC layer) */
   uint32_t txpdu_dd_pkts;      /* aggregated number of dropped or discarded tx packets by RLC */
   uint32_t txpdu_dd_bytes;     /* aggregated amount of bytes dropped or discarded tx packets by RLC */
   uint32_t txpdu_retx_pkts;    /* aggregated number of tx pdus/pkts to be re-transmitted (only applicable to RLC AM) */
@@ -50,10 +49,8 @@ typedef struct {
   uint32_t txpdu_segmented;    /* aggregated number of segmentations */
   uint32_t txpdu_status_pkts;  /* aggregated number of tx status pdus/pkts (only applicable to RLC AM) */
   uint32_t txpdu_status_bytes; /* aggregated amount of tx status bytes  (only applicable to RLC AM) */
-  /* TODO? */
-  uint32_t txbuf_occ_bytes;    /* current tx buffer occupancy in terms of amount of bytes (average: NOT IMPLEMENTED) */
-  /* TODO? */
-  uint32_t txbuf_occ_pkts;     /* current tx buffer occupancy in terms of number of packets (average: NOT IMPLEMENTED) */
+  uint32_t txbuf_occ_bytes;    /* (IMPLEMENTED) transmitting bytes currently in buffer */
+  uint32_t txbuf_occ_pkts;     /* TODO: current tx buffer occupancy in terms of number of packets (average: NOT IMPLEMENTED) */
   /* txbuf_wd_ms: the time window for which the txbuf  occupancy value is obtained - NOT IMPLEMENTED */
 
   /* RX */
@@ -70,31 +67,28 @@ typedef struct {
   /* rxpdu_rotout_ms: flag indicating rx reordering  timeout in ms - NOT IMPLEMENTED */
   /* rxpdu_potout_ms: flag indicating the poll retransmit time out in ms - NOT IMPLEMENTED */
   /* rxpdu_sptout_ms: flag indicating status prohibit timeout in ms - NOT IMPLEMENTED */
-  /* TODO? */
-  uint32_t rxbuf_occ_bytes;    /* current rx buffer occupancy in terms of amount of bytes (average: NOT IMPLEMENTED) */
-  /* TODO? */
-  uint32_t rxbuf_occ_pkts;     /* current rx buffer occupancy in terms of number of packets (average: NOT IMPLEMENTED) */
+  uint32_t rxbuf_occ_bytes;    /* (IMPLEMENTED) received bytes currently in buffer */
+  uint32_t rxbuf_occ_pkts;     /* TODO: current rx buffer occupancy in terms of number of packets (average: NOT IMPLEMENTED) */
 
   /* SDU stats */
   /* TX */
   uint32_t txsdu_pkts;         /* number of SDUs delivered */
-  uint32_t txsdu_bytes;        /* number of bytes of SDUs delivered */
+  uint64_t txsdu_bytes;        /* (UPDATED) number of SDUs bytes successfully transmitted so far (counter) */
+  /* Average time for an SDU to be passed to MAC:
+   * Actually measures the time it takes for THE FULL SDU to be passed to MAC FOR THE FIRST TIME.
+   * Since the MAC schedules in advance, it does not measure the time of
+   * transmission over the air, just the time to reach the MAC layer.
+   * => to control it, 'txsdu_wt_us' that measures the current HOL-delay is added.
+   */
+  double txsdu_avg_time_to_tx; /* (100ms-windowed) per-packet sojourn (SDU to PDU) in microseconds */
+  uint32_t txsdu_wt_us;        /* HOL delay of the current radio bearer, in microseconds */
 
   /* RX */
   uint32_t rxsdu_pkts;         /* number of SDUs received */
-  uint32_t rxsdu_bytes;        /* number of bytes of SDUs received */
+  uint64_t rxsdu_bytes;        /* (UPDATED) number of SDUs bytes arrived so far (counter) */
   uint32_t rxsdu_dd_pkts;      /* number of dropped or discarded SDUs */
   uint32_t rxsdu_dd_bytes;     /* number of bytes of SDUs dropped or discarded */
 
-  /* Average time for an SDU to be passed to MAC.
-   * Actually measures the time it takes for any part of an SDU to be
-   * passed to MAC for the first time, that is: the first TX of (part of) the
-   * SDU.
-   * Since the MAC schedules in advance, it does not measure the time of
-   * transmission over the air, just the time to reach the MAC layer.
-   */
-  double txsdu_avg_time_to_tx;
-
 } nr_rlc_statistics_t;
 
 typedef struct {

openair2/LAYER2/nr_rlc/nr_rlc_entity_am.c

@@ -224,7 +224,8 @@ static void reassemble_and_deliver(nr_rlc_entity_am_t *entity, int sn)
                              sdu, so);
 
   entity->common.stats.txsdu_pkts++;
-  entity->common.stats.txsdu_bytes += so;
+  /* AM 'txsdu_bytes' now only count successfully transmitted bytes */
+  // entity->common.stats.txsdu_bytes += so;
 }
 
 static void reception_actions(nr_rlc_entity_am_t *entity, nr_rlc_pdu_t *pdu)
@@ -484,6 +485,8 @@ process_wait_list_head:
           end_wait_list = prev_wait_list;
         if (nr_rlc_free_sdu_segment(cur_wait_list)) {
           entity->tx_size -= sdu_size;
+          // Wait-ACK: count as successfully transmitted bytes
+          entity->common.stats.txsdu_bytes += sdu_size;
           entity->common.sdu_successful_delivery(
               entity->common.sdu_successful_delivery_data,
               (nr_rlc_entity_t *)entity, upper_layer_id);
@@ -546,6 +549,8 @@ process_retransmit_list_head:
                                             + cur->size;
         if (nr_rlc_free_sdu_segment(cur)) {
           entity->tx_size -= sdu_size;
+          // Retransmit-ACK: count as successfully transmitted bytes
+          entity->common.stats.txsdu_bytes += sdu_size;
           entity->common.sdu_successful_delivery(
               entity->common.sdu_successful_delivery_data,
               (nr_rlc_entity_t *)entity, upper_layer_id);
@@ -604,6 +609,8 @@ nacks_done:
       end_wait_list = prev_wait_list;
     if (nr_rlc_free_sdu_segment(cur_wait_list)) {
       entity->tx_size -= sdu_size;
+      // Wait-NACK done: count as successfully transmitted bytes
+      entity->common.stats.txsdu_bytes += sdu_size;
       entity->common.sdu_successful_delivery(
           entity->common.sdu_successful_delivery_data,
           (nr_rlc_entity_t *)entity, upper_layer_id);
@@ -625,6 +632,8 @@ nacks_done:
                                         + cur->size;
     if (nr_rlc_free_sdu_segment(cur)) {
       entity->tx_size -= sdu_size;
+      // Retransmit-NACK done: count as successfully transmitted bytes
+      entity->common.stats.txsdu_bytes += sdu_size;
       entity->common.sdu_successful_delivery(
           entity->common.sdu_successful_delivery_data,
           (nr_rlc_entity_t *)entity, upper_layer_id);
@@ -1619,11 +1628,11 @@ static int generate_tx_pdu(nr_rlc_entity_am_t *entity, char *buffer, int size)
   entity->common.stats.txpdu_pkts++;
   entity->common.stats.txpdu_bytes += ret_size;
 
-  if (sdu->sdu->time_of_arrival) {
+  /* No need to 'zero' time-of-arrival; 
+  Segmented packets do need to be duplicated in time-sensitive use cases */
+  if (entity->common.avg_time_is_on) {
     uint64_t time_now = time_average_now();
     uint64_t waited_time = time_now - sdu->sdu->time_of_arrival;
-    /* set time_of_arrival to 0 so as to update stats only once */
-    sdu->sdu->time_of_arrival = 0;
     time_average_add(entity->common.txsdu_avg_time_to_tx, time_now, waited_time);
   }
 
@@ -1681,7 +1690,6 @@ void nr_rlc_entity_am_recv_sdu(nr_rlc_entity_t *_entity,
   nr_rlc_sdu_segment_t *sdu;
 
   entity->common.stats.rxsdu_pkts++;
-  entity->common.stats.rxsdu_bytes += size;
 
   if (size > NR_SDU_MAX) {
     LOG_E(RLC, "%s:%d:%s: fatal: SDU size too big (%d bytes)\n",
@@ -1705,6 +1713,8 @@ void nr_rlc_entity_am_recv_sdu(nr_rlc_entity_t *_entity,
   }
 
   entity->tx_size += size;
+  // SDU received: Count as arrival bytes
+  entity->common.stats.rxsdu_bytes += size;
 
   sdu = nr_rlc_new_sdu(buffer, size, sdu_id);
 
@@ -1899,6 +1909,10 @@ void nr_rlc_entity_am_discard_sdu(nr_rlc_entity_t *_entity, int sdu_id)
                                     + cur->size;
 
   entity->tx_size -= cur->sdu->size;
+
+  /* Uncomment to assert if SDU are ever discarded */
+  // assert(0 != 0 && "[RLC-TRAP] SDU discard should never be reached!");
+
   nr_rlc_free_sdu_segment(cur);
 }
 

openair2/LAYER2/nr_rlc/nr_rlc_entity_tm.c

@@ -79,11 +79,11 @@ static int generate_tx_pdu(nr_rlc_entity_tm_t *entity, char *buffer, int size)
   entity->common.stats.txpdu_pkts++;
   entity->common.stats.txpdu_bytes += size;
 
-  if (sdu->sdu->time_of_arrival) {
+  /* No need to 'zero' time-of-arrival; 
+  Segmented packets do need to be duplicated in time-sensitive use cases */
+  if (entity->common.avg_time_is_on) {
     uint64_t time_now = time_average_now();
     uint64_t waited_time = time_now - sdu->sdu->time_of_arrival;
-    /* set time_of_arrival to 0 so as to update stats only once */
-    sdu->sdu->time_of_arrival = 0;
     time_average_add(entity->common.txsdu_avg_time_to_tx, time_now, waited_time);
   }
 

openair2/LAYER2/nr_rlc/nr_rlc_entity_um.c

@@ -521,11 +521,11 @@ static int generate_tx_pdu(nr_rlc_entity_um_t *entity, char *buffer, int size)
   entity->common.stats.txpdu_pkts++;
   entity->common.stats.txpdu_bytes += size;
 
-  if (sdu->sdu->time_of_arrival) {
+  /* No need to 'zero' time-of-arrival; 
+  Segmented packets do need to be duplicated in time-sensitive use cases */
+  if (entity->common.avg_time_is_on) {
     uint64_t time_now = time_average_now();
     uint64_t waited_time = time_now - sdu->sdu->time_of_arrival;
-    /* set time_of_arrival to 0 so as to update stats only once */
-    sdu->sdu->time_of_arrival = 0;
     time_average_add(entity->common.txsdu_avg_time_to_tx, time_now, waited_time);
   }
 

openair2/LAYER2/nr_rlc/nr_rlc_oai_api.c

@@ -1070,6 +1070,12 @@ const bool nr_rlc_get_statistics(
   if (rb != NULL) {
     rb->get_stats(rb, out);
     ret = true;
+
+    // Patch buffer status using OAI results (no need to change anything in the RB)
+    // rb->set_time(rb, nr_rlc_current_time);
+    nr_rlc_entity_buffer_status_t oai_stat = rb->buffer_status(rb, 1000*1000);
+    out->rxbuf_occ_bytes = oai_stat.status_size;
+    out->txbuf_occ_bytes = oai_stat.tx_size + oai_stat.retx_size;
   } else {
     ret = false;
   }

openair2/LAYER2/nr_rlc/nr_rlc_oai_api.h

@@ -35,6 +35,8 @@
 #include "NR_RadioBearerConfig.h"
 #include "NR_CellGroupConfig.h"
 #include "openair2/RRC/NR/nr_rrc_proto.h"
+#include "nr_rlc_ue_manager.h"
+
 
 struct NR_RLC_Config;
 struct NR_LogicalChannelConfig;
@@ -67,3 +69,5 @@ void nr_rlc_activate_srb0(int rnti, struct gNB_MAC_INST_s *mac, void *rawUE,
                                      const uint8_t         *sdu,
                                      sdu_size_t             sdu_len,
                                      void                  *rawUE));
+
+const bool nr_rlc_get_statistics(int rnti, int srb_flag, int rb_id, nr_rlc_statistics_t *out);