Try to send data using writev() to reduce copying and system calls.

send queue, and read queue.

CMakeLists.txt

@@ -27,6 +27,7 @@ find_package(Sqlite3)
 
 include(TestBigEndian)
 include(CheckSymbolExists)
+include(CheckFunctionExists)
 include(CheckIncludeFile)
 include(CheckTypeSize)
 
@@ -69,9 +70,19 @@ check_include_file(sys/types.h HAVE_SYS_TYPES_H)
 if (HAVE_SYS_TYPES_H)
 set (CMAKE_EXTRA_INCLUDE_FILES ${CMAKE_EXTRA_INCLUDE_FILES} "sys/types.h")
 endif()
-check_type_size( ssize_t SSIZE_T )
+
+check_include_file(sys/uio.h HAVE_SYS_UIO_H)
+if (HAVE_SYS_UIO_H)
+set (CMAKE_EXTRA_INCLUDE_FILES ${CMAKE_EXTRA_INCLUDE_FILES} "sys/uio.h")
+endif()
+
+check_type_size(ssize_t SSIZE_T)
 check_symbol_exists(memmem string.h HAVE_MEMMEM)
 check_symbol_exists(strndup string.h HAVE_STRNDUP)
+check_function_exists(writev HAVE_FUNC_WRITEV)
+check_function_exists(pwritev HAVE_FUNC_PWRITEV)
+check_function_exists(readv HAVE_FUNC_WRITEV)
+check_function_exists(preadv HAVE_FUNC_PWRITEV)
 
 include_directories("${PROJECT_SOURCE_DIR}")
 include_directories(${SQLITE3_INCLUDE_DIRS})

src/core/ioqueue.c

@@ -19,6 +19,23 @@
 
 #include "uhub.h"
 
+struct ioq_send
+{
+  size_t               size;      /** Size of send queue (in bytes, not messages) */
+  size_t               offset;    /** Queue byte offset in the first message. Should be 0 unless a partial write. */
+#ifdef SSL_SUPPORT
+  size_t               last_send; /** When using SSL, one have to send the exact same buffer and length if a write cannot complete. */
+#endif
+  struct linked_list*  queue;     /** List of queued messages (struct adc_message) */
+};
+
+struct ioq_recv
+{
+  char* buf;
+  size_t size;
+};
+
+
 #ifdef DEBUG_SENDQ
 static void debug_msg(const char* prefix, struct adc_message* msg)
 {
@@ -147,6 +164,42 @@ int ioq_send_send(struct ioq_send* q, struct net_connection* con)
   struct adc_message* msg = list_get_first(q->queue);
   if (!msg) return 0;
   uhub_assert(msg->cache && *msg->cache);
+
+#ifdef HAVE_FUNC_WRITEV
+#define MAX_IOVEC 32
+  struct iovec vec[MAX_IOVEC];
+  size_t n = 0;
+  vec[0].iov_base = msg->cache + q->offset;
+  vec[0].iov_len = msg->length - q->offset;
+
+  for (struct adc_message* tmp = (struct adc_message*) list_get_next(q->queue), n = 1; tmp && n < MAX_IOVEC; tmp = (struct adc_message*) list_get_next(q->queue), n++)
+  {
+    vec[n].iov_base = msg->cache;
+    vec[n].iov_len = msg->length;
+  }
+
+  ret = net_con_writev(con, &iovec, n);
+
+  if (ret > 0)
+  {
+    while (ret > 0)
+    {
+      if (ret >= (msg->length - q->offset))
+      {
+        ret -= (msg->length - q->offset);
+        q->offset = 0;
+        ioq_send_remove(q, msg);
+      }
+      else
+      {
+        q->offset += ret;
+        return 0;
+      }
+    }
+    return 1;
+  }
+  return ret;
+#else
 	ret = net_con_send(con, msg->cache + q->offset, msg->length - q->offset);
 
 	if (ret > 0)
@@ -159,8 +212,10 @@ int ioq_send_send(struct ioq_send* q, struct net_connection* con)
 		return 1;
 	}
 	return ret;
+#endif
 }
 
+
 int ioq_send_is_empty(struct ioq_send* q)
 {
 	return (q->size - q->offset) == 0;

src/core/ioqueue.h

@@ -21,25 +21,8 @@
 #define HAVE_UHUB_IO_QUEUE_H
 
 struct adc_message;
-struct linked_list;
+struct ioq_send;
-typedef int (*ioq_write)(void* desc, const void* buf, size_t len);
+struct ioq_recv;
-typedef int (*ioq_read)(void* desc, void* buf, size_t len);
-
-struct ioq_send
-{
-	size_t               size;      /** Size of send queue (in bytes, not messages) */
-	size_t               offset;    /** Queue byte offset in the first message. Should be 0 unless a partial write. */
-#ifdef SSL_SUPPORT
-	size_t               last_send; /** When using SSL, one have to send the exact same buffer and length if a write cannot complete. */
-#endif
-	struct linked_list*  queue;     /** List of queued messages (struct adc_message) */
-};
-
-struct ioq_recv
-{
-	char* buf;
-	size_t size;
-};
 
 /**
  * Create a send queue

src/core/route.c

@@ -80,13 +80,13 @@ static int check_send_queue(struct hub_info* hub, struct hub_user* user, struct
 	if (user_flag_get(user, flag_user_list))
 		return 1;
 
-	if ((user->send_queue->size + msg->length) > get_max_send_queue(hub))
+	if ((ioq_send_get_bytes(user->send_queue) + msg->length) > get_max_send_queue(hub))
 	{
 		LOG_WARN("send queue overflowed, message discarded.");
 		return -1;
 	}
 
-	if (user->send_queue->size > get_max_send_queue_soft(hub))
+	if (ioq_send_get_bytes(user->send_queue) > get_max_send_queue_soft(hub))
 	{
 		LOG_WARN("send queue soft overflowed.");
 		return 0;

src/network/connection.c

@@ -57,6 +57,48 @@ ssize_t net_con_send(struct net_connection* con, const void* buf, size_t len)
 	return ret;
 }
 
+#ifdef HAVE_FUNC_WRITEV
+ssize_t net_con_writev(struct net_connection* con, const struct iovec* iov, size_t iocnt)
+{
+  int ret;
+#ifdef SSL_SUPPORT
+  if (!con->ssl)
+  {
+#endif
+    ret = writev(con->sd, iovec, (int) iocnt);
+    if (ret == -1)
+    {
+      if (is_blocked_or_interrupted())
+        return 0;
+      return -1;
+    }
+#ifdef SSL_SUPPORT
+  }
+  else
+  {
+    ssize_t total = 0;
+    ret = 0;
+    while (iocnt--)
+    {
+      ret = net_ssl_send(con, buf, len);
+      if (ret >= 0)
+        total += ret;
+      else
+      {
+        break;
+      }
+    }
+
+    if (total == 0 && !is_blocked_or_interrupted())
+        return -1;
+
+    return total;
+  }
+#endif /* SSL_SUPPORT */
+  return ret;
+}
+#endif
+
 ssize_t net_con_recv(struct net_connection* con, void* buf, size_t len)
 {
 	int ret;

src/network/connection.h

@@ -92,6 +92,11 @@ extern void net_con_close(struct net_connection* con);
  */
 extern ssize_t net_con_send(struct net_connection* con, const void* buf, size_t len);
 
+
+#ifdef HAVE_FUNC_WRITEV
+extern ssize_t net_con_writev(struct net_connection* con, const struct iovec* iov, size_t iocnt);
+#endif
+
 /**
  * Receive data
  *

src/system.h.in

@@ -88,6 +88,11 @@
 #cmakedefine HAVE_STRNDUP
 #cmakedefine HAVE_MEMMEM
 
+#cmakedefine HAVE_SYS_UIO_H
+#ifdef HAVE_SYS_TYPES_H
+#include <sys/uio.h>
+#endif
+
 /* printf support for size_t and uint64_t */
 #if defined(WIN32)
 #define PRINTF_SIZE_T "%Iu"