Merge remote-tracking branch 'origin/rlc-optimization' into integration_2024_w44 (!3061)

RLC optimization

Two improvements:

- using functions instead of function pointers which enables inlining
- avoid 1 malloc/free per SDU

Benchmark results:

before:

    BM_nr_rlc_am_entity/20000           5036721 ns      5036541 ns          138
    BM_nr_rlc_am_entity/20000           5032061 ns      5031849 ns          138
    BM_nr_rlc_am_entity/20000           5037071 ns      5037056 ns          138
    BM_nr_rlc_am_entity/20000           5035472 ns      5035248 ns          138
    BM_nr_rlc_am_entity/20000           5032860 ns      5032681 ns          138
    BM_nr_rlc_am_entity/20000_mean      5034837 ns      5034675 ns            5
    BM_nr_rlc_am_entity/20000_median    5035472 ns      5035248 ns            5
    BM_nr_rlc_am_entity/20000_stddev       2267 ns         2315 ns            5
    BM_nr_rlc_am_entity/20000_cv           0.05 %          0.05 %             5

after:

    BM_nr_rlc_am_entity/20000           4974403 ns      4974202 ns          140
    BM_nr_rlc_am_entity/20000           4976705 ns      4976444 ns          140
    BM_nr_rlc_am_entity/20000           5004550 ns      5004508 ns          140
    BM_nr_rlc_am_entity/20000           4974652 ns      4974460 ns          140
    BM_nr_rlc_am_entity/20000           4976447 ns      4976225 ns          140
    BM_nr_rlc_am_entity/20000_mean      4981351 ns      4981168 ns            5
    BM_nr_rlc_am_entity/20000_median    4976447 ns      4976225 ns            5
    BM_nr_rlc_am_entity/20000_stddev      13009 ns        13087 ns            5
    BM_nr_rlc_am_entity/20000_cv           0.26 %          0.26 %             5

openair2/LAYER2/nr_rlc/nr_rlc_entity_am.c

@@ -55,7 +55,7 @@ static int modulus_rx(nr_rlc_entity_am_t *entity, int a)
   return r;
 }
 
-static int modulus_tx(nr_rlc_entity_am_t *entity, int a)
+static inline int modulus_tx(nr_rlc_entity_am_t *entity, int a)
 {
   int r = a - entity->tx_next_ack;
   if (r < 0) r += entity->sn_modulus;
@@ -76,12 +76,38 @@ static int sn_compare_rx(void *_entity, int a, int b)
   return modulus_rx(entity, a) - modulus_rx(entity, b);
 }
 
-static int sn_compare_tx(void *_entity, int a, int b)
+static inline int sn_compare_tx(void *_entity, int a, int b)
 {
   nr_rlc_entity_am_t *entity = _entity;
   return modulus_tx(entity, a) - modulus_tx(entity, b);
 }
 
+nr_rlc_sdu_segment_t *nr_rlc_tx_sdu_segment_list_add(nr_rlc_entity_am_t *entity,
+    nr_rlc_sdu_segment_t *list, nr_rlc_sdu_segment_t *sdu_segment)
+{
+  nr_rlc_sdu_segment_t head;
+  nr_rlc_sdu_segment_t *cur;
+  nr_rlc_sdu_segment_t *prev;
+
+  head.next = list;
+  cur = list;
+  prev = &head;
+
+  /* order is by 'sn', if 'sn' is the same then order is by 'so' */
+  while (cur != NULL) {
+    /* check if 'sdu_segment' is before 'cur' in the list */
+    if (sn_compare_tx(entity, cur->sdu->sn, sdu_segment->sdu->sn) > 0 ||
+        (cur->sdu->sn == sdu_segment->sdu->sn && cur->so > sdu_segment->so)) {
+      break;
+    }
+    prev = cur;
+    cur = cur->next;
+  }
+  prev->next = sdu_segment;
+  sdu_segment->next = cur;
+  return head.next;
+}
+
 static int segment_already_received(nr_rlc_entity_am_t *entity,
     int sn, int so, int size)
 {
@@ -1580,7 +1606,7 @@ static int generate_retx_pdu(nr_rlc_entity_am_t *entity, char *buffer,
           && sdu->so > entity->wait_end->so))
     nr_rlc_sdu_segment_list_append(&entity->wait_list, &entity->wait_end, sdu);
   else {
-    entity->wait_list = nr_rlc_sdu_segment_list_add(sn_compare_tx, entity,
+    entity->wait_list = nr_rlc_tx_sdu_segment_list_add(entity,
                             entity->wait_list, sdu);
     if (entity->wait_list->next == NULL)
       entity->wait_end = entity->wait_list;
@@ -1672,7 +1698,7 @@ static int generate_tx_pdu(nr_rlc_entity_am_t *entity, char *buffer, int size)
           && sdu->so > entity->wait_end->so))
     nr_rlc_sdu_segment_list_append(&entity->wait_list, &entity->wait_end, sdu);
   else {
-    entity->wait_list = nr_rlc_sdu_segment_list_add(sn_compare_tx, entity,
+    entity->wait_list = nr_rlc_tx_sdu_segment_list_add(entity,
                             entity->wait_list, sdu);
     if (entity->wait_list->next == NULL)
       entity->wait_end = entity->wait_list;
@@ -1881,7 +1907,7 @@ static void check_t_poll_retransmit(nr_rlc_entity_am_t *entity)
           cur->sdu->sn, cur->so, cur->size, cur->sdu->retx_count);
 
     /* put in retransmit list */
-    entity->retransmit_list = nr_rlc_sdu_segment_list_add(sn_compare_tx, entity,
+    entity->retransmit_list = nr_rlc_tx_sdu_segment_list_add(entity,
                                   entity->retransmit_list, cur);
 
     cur = entity->wait_list;
@@ -2064,3 +2090,4 @@ int nr_rlc_entity_am_available_tx_space(nr_rlc_entity_t *_entity)
   nr_rlc_entity_am_t *entity = (nr_rlc_entity_am_t *)_entity;
   return entity->tx_maxsize - entity->tx_size;
 }
+

openair2/LAYER2/nr_rlc/nr_rlc_sdu.c

@@ -30,7 +30,11 @@ nr_rlc_sdu_segment_t *nr_rlc_new_sdu(
     char *buffer, int size,
     int upper_layer_id)
 {
-  nr_rlc_sdu_t *sdu         = calloc(1, sizeof(nr_rlc_sdu_t));
+  /* allocate sdu header and data together */
+  nr_rlc_sdu_t *sdu = malloc(sizeof(nr_rlc_sdu_t) + size);
+  /* only memset the header */
+  memset(sdu, 0 , sizeof(*sdu));
+
   nr_rlc_sdu_segment_t *ret = calloc(1, sizeof(nr_rlc_sdu_segment_t));
   if (sdu == NULL || ret == NULL)
     goto oom;
@@ -38,9 +42,7 @@ nr_rlc_sdu_segment_t *nr_rlc_new_sdu(
   sdu->ref_count      = 1;
   sdu->sn             = -1;                 /* set later */
   sdu->upper_layer_id = upper_layer_id;
-  sdu->data           = malloc(size);
-  if (sdu->data == NULL)
-    goto oom;
+  sdu->data           = (char*)(sdu + 1);
   memcpy(sdu->data, buffer, size);
   sdu->size           = size;
   sdu->retx_count     = -1;
@@ -64,7 +66,6 @@ int nr_rlc_free_sdu_segment(nr_rlc_sdu_segment_t *sdu)
 
   sdu->sdu->free_count++;
   if (sdu->sdu->free_count == sdu->sdu->ref_count) {
-    free(sdu->sdu->data);
     free(sdu->sdu);
     ret = 1;
   }
@@ -87,33 +88,6 @@ void nr_rlc_sdu_segment_list_append(nr_rlc_sdu_segment_t **list,
   *end = sdu;
 }
 
-nr_rlc_sdu_segment_t *nr_rlc_sdu_segment_list_add(
-    int (*sn_compare)(void *, int, int), void *sn_compare_data,
-    nr_rlc_sdu_segment_t *list, nr_rlc_sdu_segment_t *sdu_segment)
-{
-  nr_rlc_sdu_segment_t head;
-  nr_rlc_sdu_segment_t *cur;
-  nr_rlc_sdu_segment_t *prev;
-
-  head.next = list;
-  cur = list;
-  prev = &head;
-
-  /* order is by 'sn', if 'sn' is the same then order is by 'so' */
-  while (cur != NULL) {
-    /* check if 'sdu_segment' is before 'cur' in the list */
-    if (sn_compare(sn_compare_data, cur->sdu->sn, sdu_segment->sdu->sn) > 0 ||
-        (cur->sdu->sn == sdu_segment->sdu->sn && cur->so > sdu_segment->so)) {
-      break;
-    }
-    prev = cur;
-    cur = cur->next;
-  }
-  prev->next = sdu_segment;
-  sdu_segment->next = cur;
-  return head.next;
-}
-
 void nr_rlc_free_sdu_segment_list(nr_rlc_sdu_segment_t *l)
 {
   nr_rlc_sdu_segment_t *cur;

openair2/LAYER2/nr_rlc/nr_rlc_sdu.h

@@ -61,9 +61,6 @@ int nr_rlc_free_sdu_segment(nr_rlc_sdu_segment_t *sdu);
 void nr_rlc_sdu_segment_list_append(nr_rlc_sdu_segment_t **list,
                                     nr_rlc_sdu_segment_t **end,
                                     nr_rlc_sdu_segment_t *sdu);
-nr_rlc_sdu_segment_t *nr_rlc_sdu_segment_list_add(
-    int (*sn_compare)(void *, int, int), void *sn_compare_data,
-    nr_rlc_sdu_segment_t *list, nr_rlc_sdu_segment_t *sdu_segment);
 void nr_rlc_free_sdu_segment_list(nr_rlc_sdu_segment_t *l);
 
 #endif /* _NR_RLC_SDU_H_ */