Changeset bbf159a in mainline

Timestamp:

2011-12-13T17:06:25Z (12 years ago)

Author:

Jiri Svoboda <jiri@…>

Branches:

lfn, master, serial, ticket/834-toolchain-update, topic/msim-upgrade, topic/simplify-dev-export

Children:

7a8c1c4e

Parents:

0d29e0cd

Message:

Eliminate busy waiting when TCP send buffer is full.

Location:

uspace/srv/net/tl/tcp

Files:

• conn.c (modified) (2 diffs)
• tcp_type.h (modified) (1 diff)
• tqueue.c (modified) (5 diffs)
• ucall.c (modified) (2 diffs)

uspace/srv/net/tl/tcp/conn.c

@@ -93 +93 @@
 
         /** Allocate send buffer */
+        fibril_mutex_initialize(&conn->snd_buf_lock);
+        fibril_condvar_initialize(&conn->snd_buf_cv);
         conn->snd_buf_size = SND_BUF_SIZE;
         conn->snd_buf_used = 0;
@@ -287 +289 @@
 
         fibril_condvar_broadcast(&conn->rcv_buf_cv);
+        fibril_condvar_broadcast(&conn->snd_buf_cv);
 }
 

uspace/srv/net/tl/tcp/tcp_type.h

@@ -204 +204 @@
         /** Send buffer contains FIN */
         bool snd_buf_fin;
+        /** Send buffer lock */
+        fibril_mutex_t snd_buf_lock;
+        /** Send buffer CV. Broadcast when space is made available in buffer */
+        fibril_condvar_t snd_buf_cv;
 
         /** Send unacknowledged */

uspace/srv/net/tl/tcp/tqueue.c

@@ -167 +167 @@
         log_msg(LVL_DEBUG, "%s: tcp_tqueue_new_data()", conn->name);
 
+        fibril_mutex_lock(&conn->snd_buf_lock);
+
         /* Number of free sequence numbers in send window */
         avail_wnd = (conn->snd_una + conn->snd_wnd) - conn->snd_nxt;
@@ -176 +178 @@
             xfer_seqlen);
 
-        if (xfer_seqlen == 0)
-                return;
+        if (xfer_seqlen == 0) {
+                fibril_mutex_unlock(&conn->snd_buf_lock);
+                return;
+        }
 
         /* XXX Do not always send immediately */
@@ -188 +192 @@
                 /* We are sending out FIN */
                 ctrl = CTL_FIN;
-                tcp_conn_fin_sent(conn);
         } else {
                 ctrl = 0;
@@ -195 +198 @@
         seg = tcp_segment_make_data(ctrl, conn->snd_buf, data_size);
         if (seg == NULL) {
+                fibril_mutex_unlock(&conn->snd_buf_lock);
                 log_msg(LVL_ERROR, "Memory allocation failure.");
                 return;
@@ -206 +210 @@
         if (send_fin)
                 conn->snd_buf_fin = false;
+
+        fibril_condvar_broadcast(&conn->snd_buf_cv);
+        fibril_mutex_unlock(&conn->snd_buf_lock);
+
+        if (send_fin)
+                tcp_conn_fin_sent(conn);
 
         tcp_tqueue_seg(conn, seg);

uspace/srv/net/tl/tcp/ucall.c

@@ -121 +121 @@
         }
 
-        if (conn->snd_buf_fin)
+        fibril_mutex_lock(&conn->snd_buf_lock);
+
+        if (conn->snd_buf_fin) {
+                fibril_mutex_unlock(&conn->snd_buf_lock);
                 return TCP_ECLOSING;
+        }
 
         while (size > 0) {
                 buf_free = conn->snd_buf_size - conn->snd_buf_used;
                 while (buf_free == 0 && !conn->reset) {
-                        tcp_tqueue_new_data(conn);
+                        log_msg(LVL_DEBUG, "%s: buf_free == 0, waiting.",
+                            conn->name);
+                        fibril_condvar_wait(&conn->snd_buf_cv,
+                            &conn->snd_buf_lock);
                         buf_free = conn->snd_buf_size - conn->snd_buf_used;
                 }
 
-                if (conn->reset)
+                if (conn->reset) {
+                        fibril_mutex_unlock(&conn->snd_buf_lock);
                         return TCP_ERESET;
+                }
 
                 xfer_size = min(size, buf_free);
@@ -141 +150 @@
                 conn->snd_buf_used += xfer_size;
                 size -= xfer_size;
-        }
-
+
+                fibril_mutex_unlock(&conn->snd_buf_lock);
+                tcp_tqueue_new_data(conn);
+                fibril_mutex_lock(&conn->snd_buf_lock);
+        }
+
+        fibril_mutex_unlock(&conn->snd_buf_lock);
         tcp_tqueue_new_data(conn);