Add configuration support for TCP Write Buffering

include/nuttx/net/uip/uipopt.h

@@ -294,7 +294,7 @@
 #   define CONFIG_NET_NTCP_READAHEAD_BUFFERS 4
 #  endif
 
-  /* The size of the TCP read buffer size */
+  /* The size of one TCP read buffer */
 
 #  ifndef CONFIG_NET_TCP_READAHEAD_BUFSIZE
 #    define CONFIG_NET_TCP_READAHEAD_BUFSIZE UIP_TCP_MSS
@@ -305,6 +305,24 @@
 #  undef CONFIG_NET_NTCP_READAHEAD_BUFFERS
 #endif
 
+#ifdef CONFIG_NET_TCP_WRITE_BUFFERS
+  /* Number of TCP write buffers */
+
+#  ifndef CONFIG_NET_NTCP_WRITE_BUFFERS
+#    define CONFIG_NET_NTCP_WRITE_BUFFERS 1
+#  endif
+
+  /* The size of one TCP write buffer */
+
+#  ifndef CONFIG_NET_TCP_WRITE_BUFSIZE
+#    define CONFIG_NET_TCP_WRITE_BUFSIZE UIP_TCP_MSS
+#  endif
+
+#else
+#  undef CONFIG_NET_TCP_WRITE_BUFSIZE
+#  undef CONFIG_NET_NTCP_WRITE_BUFFERS
+#endif
+
 /* Delay after receive to catch a following packet.  No delay should be
  * required if TCP/IP read-ahead buffering is enabled.
  */

net/Kconfig

@@ -103,6 +103,7 @@ config NET_TCP
 		TCP support on or off
 
 if NET_TCP
+
 config NET_TCP_CONNS
 	int "Number of TCP/IP connections"
 	default 8
@@ -118,6 +119,14 @@ config NET_MAX_LISTENPORTS
 config NET_TCP_READAHEAD
 	bool "Enabled TCP/IP read-ahead buffering"
 	default y
+	---help---
+		Read-ahead buffers allows buffering of TCP/IP packets when there is no
+		receive in place to catch the TCP packet.  In that case, the packet
+		will be retained in the NuttX read-ahead buffers.
+
+		You might want to disable TCP/IP read-ahead buffering on a highly
+		memory constrained system that does not have any TCP/IP packet rate
+		issues.
 
 if NET_TCP_READAHEAD
 
@@ -140,14 +149,43 @@ config NET_NTCP_READAHEAD_BUFFERS
 		receive in place to catch the TCP packet.  In that case, the packet
 		will be retained in the NuttX read-ahead buffers.
 
-		This setting specifies the number of TCP/IP read-ahead buffers  This
+		This setting specifies the number of TCP/IP read-ahead buffers.
-		value can be set to zero to disable all TCP/IP read-ahead buffering.
-		You might want to disable TCP/IP read-ahead buffering on a highly
-		memory constained system that does not have any TCP/IP packet rate
-		issues.
 
 endif # NET_TCP_READAHEAD
 
+config NET_TCP_WRITE_BUFFERS
+	bool "Enabled TCP/IP write buffering"
+	default n
+	---help---
+		Write buffers allows buffering of ongoing TCP/IP packets, providing
+		for higher performance, streamed output.
+
+		You might want to disable TCP/IP write buffering on a highly memory
+		memory constrained system where there are no performance issues.
+
+if NET_TCP_WRITE_BUFFERS
+
+config NET_TCP_WRITE_BUFSIZE
+	int "TCP/IP write buffer size"
+	default 562
+	---help---
+		Write buffers allows buffering of ongoing TCP/IP packets, providing
+		for higher performance, streamed output.
+
+		This setting specifies the size of one TCP/IP write buffer. This
+		should best be a equal to the maximum packet size (NET_BUFSIZE).
+
+config NET_NTCP_WRITE_BUFFERS
+	int "Number of TCP/IP write buffers"
+	default 8
+	---help---
+		Write buffers allows buffering of ongoing TCP/IP packets, providing
+		for higher performance, streamed output.
+
+		This setting specifies the number of TCP/IP write buffers.
+
+endif # NET_TCP_WRITE_BUFFERS
+
 config NET_TCP_RECVDELAY
 	int "TCP Rx delay"
 	default 0

net/uip/uip_tcpreadahead.c

@@ -47,17 +47,30 @@
 
 #include "uip_internal.h"
 
+/****************************************************************************
+ * Private Types
+ ****************************************************************************/
+
+/* Package all globals used by this logic into a structure */
+
+struct readahead_s
+{
+  /* This is the list of available write buffers */
+
+  sq_queue_t freebuffers;
+
+  /* These are the pre-allocated write buffers */
+
+  struct uip_readahead_s buffers[CONFIG_NET_NTCP_READAHEAD_BUFFERS];
+};
+
 /****************************************************************************
  * Private Data
  ****************************************************************************/
 
-/* These are the pre-allocated read-ahead buffers */
+/* This is the state of the global read-ahead resource */
 
-static struct uip_readahead_s g_buffers[CONFIG_NET_NTCP_READAHEAD_BUFFERS];
+static struct readahead_s g_readahead;
-
-/* This is the list of available read-ahead buffers */
-
-static sq_queue_t g_freebuffers;
 
 /****************************************************************************
  * Private Functions
@@ -82,10 +95,10 @@ void uip_tcpreadaheadinit(void)
 {
   int i;
 
-  sq_init(&g_freebuffers);
+  sq_init(&g_readahead.freebuffers);
   for (i = 0; i < CONFIG_NET_NTCP_READAHEAD_BUFFERS; i++)
     {
-      sq_addfirst(&g_buffers[i].rh_node, &g_freebuffers);
+      sq_addfirst(&g_readahead.buffers[i].rh_node, &g_readahead.freebuffers);
     }
 }
 
@@ -106,7 +119,7 @@ void uip_tcpreadaheadinit(void)
 
 struct uip_readahead_s *uip_tcpreadaheadalloc(void)
 {
-  return (struct uip_readahead_s*)sq_remfirst(&g_freebuffers);
+  return (struct uip_readahead_s*)sq_remfirst(&g_readahead.freebuffers);
 }
 
 /****************************************************************************
@@ -124,7 +137,7 @@ struct uip_readahead_s *uip_tcpreadaheadalloc(void)
 
 void uip_tcpreadaheadrelease(struct uip_readahead_s *buf)
 {
-  sq_addfirst(&buf->rh_node, &g_freebuffers);
+  sq_addfirst(&buf->rh_node, &g_readahead.freebuffers);
 }
 
 #endif /* CONFIG_NET && CONFIG_NET_TCP && CONFIG_NET_TCP_READAHEAD */