High throughput fixes for csma and sixlowpan

core/lib/memb.c

@@ -107,5 +107,18 @@ memb_inmemb(struct memb *m, void *ptr)
     (char *)ptr < (char *)m->mem + (m->num * m->size);
 }
 /*---------------------------------------------------------------------------*/
+int
+memb_numfree(struct memb *m)
+{
+  int i;
+  int num_free = 0;
 
+  for(i = 0; i < m->num; ++i) {
+    if(m->count[i] == 0) {
+      ++num_free;
+    }
+  }
+
+  return num_free;
+}
 /** @} */

core/lib/memb.h

@@ -130,6 +130,7 @@ char  memb_free(struct memb *m, void *ptr);
 
 int memb_inmemb(struct memb *m, void *ptr);
 
+int  memb_numfree(struct memb *m);
 
 /** @} */
 /** @} */

core/net/ipv6/sicslowpan.c

@@ -1454,6 +1454,13 @@ output(const uip_lladdr_t *localdest)
      * IPv6/HC1/HC06/HC_UDP dispatchs/headers.
      * The following fragments contain only the fragn dispatch.
      */
+    int estimated_fragments = ((int)uip_len) / ((int)MAC_MAX_PAYLOAD - SICSLOWPAN_FRAGN_HDR_LEN) + 1;
+    int freebuf = queuebuf_numfree() - 1;
+    PRINTFO("uip_len: %d, fragments: %d, free bufs: %d\n", uip_len, estimated_fragments, freebuf);
+    if(freebuf < estimated_fragments) {
+      PRINTFO("Dropping packet, not enough free bufs\n");
+      return 0;
+    }
 
     PRINTFO("Fragmentation sending packet len %d\n", uip_len);
 

core/net/mac/csma.c

@@ -108,6 +108,13 @@ struct neighbor_queue {
 #define CSMA_MAX_NEIGHBOR_QUEUES 2
 #endif /* CSMA_CONF_MAX_NEIGHBOR_QUEUES */
 
+/* The maximum number of pending packet per neighbor */
+#ifdef CSMA_CONF_MAX_PACKET_PER_NEIGHBOR
+#define CSMA_MAX_PACKET_PER_NEIGHBOR CSMA_CONF_MAX_PACKET_PER_NEIGHBOR
+#else
+#define CSMA_MAX_PACKET_PER_NEIGHBOR MAX_QUEUED_PACKETS
+#endif /* CSMA_CONF_MAX_PACKET_PER_NEIGHBOR */
+
 #define MAX_QUEUED_PACKETS QUEUEBUF_NUM
 MEMB(neighbor_memb, struct neighbor_queue, CSMA_MAX_NEIGHBOR_QUEUES);
 MEMB(packet_memb, struct rdc_buf_list, MAX_QUEUED_PACKETS);
@@ -173,8 +180,8 @@ free_packet(struct neighbor_queue *n, struct rdc_buf_list *p)
     queuebuf_free(p->buf);
     memb_free(&metadata_memb, p->ptr);
     memb_free(&packet_memb, p);
-    PRINTF("csma: free_queued_packet, queue length %d\n",
-        list_length(n->queued_packet_list));
+    PRINTF("csma: free_queued_packet, queue length %d, free packets %d\n",
+           list_length(n->queued_packet_list), memb_numfree(&packet_memb));
     if(list_head(n->queued_packet_list) != NULL) {
       /* There is a next packet. We reset current tx information */
       n->transmissions = 0;
@@ -298,7 +305,11 @@ packet_sent(void *ptr, int status, int num_transmissions)
         free_packet(n, q);
         mac_call_sent_callback(sent, cptr, status, num_tx);
       }
+    } else {
+      PRINTF("csma: no metadata\n");
     }
+  } else {
+    PRINTF("csma: seqno %d not found\n", packetbuf_attr(PACKETBUF_ATTR_MAC_SEQNO));
   }
 }
 /*---------------------------------------------------------------------------*/
@@ -344,47 +355,53 @@ send_packet(mac_callback_t sent, void *ptr)
 
   if(n != NULL) {
     /* Add packet to the neighbor's queue */
-    q = memb_alloc(&packet_memb);
-    if(q != NULL) {
-      q->ptr = memb_alloc(&metadata_memb);
-      if(q->ptr != NULL) {
-	q->buf = queuebuf_new_from_packetbuf();
-	if(q->buf != NULL) {
-	  struct qbuf_metadata *metadata = (struct qbuf_metadata *)q->ptr;
-	  /* Neighbor and packet successfully allocated */
-	  if(packetbuf_attr(PACKETBUF_ATTR_MAX_MAC_TRANSMISSIONS) == 0) {
-	    /* Use default configuration for max transmissions */
-	    metadata->max_transmissions = CSMA_MAX_MAC_TRANSMISSIONS;
-	  } else {
-	    metadata->max_transmissions =
-                  packetbuf_attr(PACKETBUF_ATTR_MAX_MAC_TRANSMISSIONS);
-	  }
-	  metadata->sent = sent;
-	  metadata->cptr = ptr;
-
-	  if(packetbuf_attr(PACKETBUF_ATTR_PACKET_TYPE) ==
-	     PACKETBUF_ATTR_PACKET_TYPE_ACK) {
-	    list_push(n->queued_packet_list, q);
-	  } else {
-	    list_add(n->queued_packet_list, q);
-	  }
-
-	  /* If q is the first packet in the neighbor's queue, send asap */
-	  if(list_head(n->queued_packet_list) == q) {
-	    ctimer_set(&n->transmit_timer, 0, transmit_packet_list, n);
-	  }
-	  return;
-	}
-	memb_free(&metadata_memb, q->ptr);
-	PRINTF("csma: could not allocate queuebuf, dropping packet\n");
+    if(list_length(n->queued_packet_list) < CSMA_MAX_PACKET_PER_NEIGHBOR) {
+      q = memb_alloc(&packet_memb);
+      if(q != NULL) {
+        q->ptr = memb_alloc(&metadata_memb);
+        if(q->ptr != NULL) {
+          q->buf = queuebuf_new_from_packetbuf();
+          if(q->buf != NULL) {
+            struct qbuf_metadata *metadata = (struct qbuf_metadata *)q->ptr;
+            /* Neighbor and packet successfully allocated */
+            if(packetbuf_attr(PACKETBUF_ATTR_MAX_MAC_TRANSMISSIONS) == 0) {
+              /* Use default configuration for max transmissions */
+              metadata->max_transmissions = CSMA_MAX_MAC_TRANSMISSIONS;
+            } else {
+              metadata->max_transmissions =
+                packetbuf_attr(PACKETBUF_ATTR_MAX_MAC_TRANSMISSIONS);
+            }
+            metadata->sent = sent;
+            metadata->cptr = ptr;
+
+            if(packetbuf_attr(PACKETBUF_ATTR_PACKET_TYPE) ==
+               PACKETBUF_ATTR_PACKET_TYPE_ACK) {
+              list_push(n->queued_packet_list, q);
+            } else {
+              list_add(n->queued_packet_list, q);
+            }
+
+            PRINTF("csma: send_packet, queue length %d, free packets %d\n",
+                   list_length(n->queued_packet_list), memb_numfree(&packet_memb));
+            /* If q is the first packet in the neighbor's queue, send asap */
+            if(list_head(n->queued_packet_list) == q) {
+              ctimer_set(&n->transmit_timer, 0, transmit_packet_list, n);
+            }
+            return;
+          }
+          memb_free(&metadata_memb, q->ptr);
+          PRINTF("csma: could not allocate queuebuf, dropping packet\n");
+        }
+        memb_free(&packet_memb, q);
+        PRINTF("csma: could not allocate queuebuf, dropping packet\n");
       }
-      memb_free(&packet_memb, q);
-      PRINTF("csma: could not allocate queuebuf, dropping packet\n");
-    }
-    /* The packet allocation failed. Remove and free neighbor entry if empty. */
-    if(list_length(n->queued_packet_list) == 0) {
-      list_remove(neighbor_list, n);
-      memb_free(&neighbor_memb, n);
+      /* The packet allocation failed. Remove and free neighbor entry if empty. */
+      if(list_length(n->queued_packet_list) == 0) {
+        list_remove(neighbor_list, n);
+        memb_free(&neighbor_memb, n);
+      }
+    } else {
+      PRINTF("csma: Neighbor queue full\n");
     }
     PRINTF("csma: could not allocate packet, dropping packet\n");
   } else {

core/net/queuebuf.c

@@ -307,6 +307,16 @@ queuebuf_init(void)
 #endif /* QUEUEBUF_STATS */
 }
 /*---------------------------------------------------------------------------*/
+int
+queuebuf_numfree(void)
+{
+  if(packetbuf_is_reference()) {
+    return memb_numfree(&refbufmem);
+  } else {
+    return memb_numfree(&bufmem);
+  }
+}
+/*---------------------------------------------------------------------------*/
 #if QUEUEBUF_DEBUG
 struct queuebuf *
 queuebuf_new_from_packetbuf_debug(const char *file, int line)

core/net/queuebuf.h

@@ -108,7 +108,9 @@ packetbuf_attr_t queuebuf_attr(struct queuebuf *b, uint8_t type);
 
 void queuebuf_debug_print(void);
 
-#endif /* QUEUEBUF_H_ */
+int queuebuf_numfree(void);
+
+#endif /* __QUEUEBUF_H__ */
 
 /** @} */
 /** @} */