samples: net: coap_server: Finetune sample parameters

Finetune coap_server sample parameters for better user experience.

Reduce the maximum retransmission count to release resources earilier in
case client is unreachable and no longer responds. Increase the maximum
number of pending retransmissions, along with the heap size (the buffers
for messages are allocated on a heap), to improve sample responsiveness,
in case multiple unreplied messages are pending retransmission.

Signed-off-by: Robert Lubos <[email protected]>

Author: rlubos

samples/net/sockets/coap_server/prj.conf

@@ -24,7 +24,7 @@ CONFIG_NET_LOG=y
 CONFIG_NET_SHELL=y
 
 CONFIG_MAIN_STACK_SIZE=2048
-CONFIG_HEAP_MEM_POOL_SIZE=2048
+CONFIG_HEAP_MEM_POOL_SIZE=4096
 
 # Configuration
 CONFIG_NET_CONFIG_SETTINGS=y

samples/net/sockets/coap_server/src/coap-server.c

@@ -24,6 +24,8 @@ LOG_MODULE_REGISTER(net_coap_server_sample, LOG_LEVEL_DBG);
 #include "ipv6.h"
 #endif
 
+#define MAX_RETRANSMIT_COUNT 2
+
 #define MAX_COAP_MSG_LEN 256
 
 #define MY_COAP_PORT 5683
@@ -44,7 +46,7 @@ LOG_MODULE_REGISTER(net_coap_server_sample, LOG_LEVEL_DBG);
 
 #define NUM_OBSERVERS 3
 
-#define NUM_PENDINGS 3
+#define NUM_PENDINGS 10
 
 /* CoAP socket fd */
 static int sock;
@@ -1020,8 +1022,7 @@ static int create_pending_request(struct coap_packet *response,
 		return -ENOMEM;
 	}
 
-	r = coap_pending_init(pending, response, addr,
-			      COAP_DEFAULT_MAX_RETRANSMIT);
+	r = coap_pending_init(pending, response, addr, MAX_RETRANSMIT_COUNT);
 	if (r < 0) {
 		return -EINVAL;
 	}