* modules/access_output/udp.c: Do not use malloc() and free() in a high

   priority thread, since these functions use an internal mutex and may
   delay the thread for up to 100 ms under heavy loads (experienced with
   the mosaic). Instead we now recycle the UDP buffers, which is
   incidentally faster than malloc()/free(). It should avoid "late
   buffer sent" messages. Also removed the --sout-udp-late option because
   "better late than never" (I changed my mind on this).

modules/access_output/udp.c

@@ -51,6 +51,7 @@
 
 #include "network.h"
 
+#define MAX_EMPTY_BLOCKS 200
 
 /*****************************************************************************
  * Module descriptor
@@ -75,10 +76,6 @@ static void Close( vlc_object_t * );
                           "of packets that will be sent at a time. It " \
                           "helps reducing the scheduling load on " \
                           "heavily-loaded systems." )
-#define LATE_TEXT N_("Late delay (ms)" )
-#define LATE_LONGTEXT N_("Late packets are dropped. This allows you to give " \
-                       "the time (in milliseconds) a packet is allowed to be" \
-                       " late.")
 #define RAW_TEXT N_("Raw write")
 #define RAW_LONGTEXT N_("If you enable this option, packets will be sent " \
                        "directly, without trying to fill the MTU (ie, " \
@@ -95,8 +92,7 @@ vlc_module_begin();
                                  VLC_TRUE );
     add_integer( SOUT_CFG_PREFIX "group", 1, NULL, GROUP_TEXT, GROUP_LONGTEXT,
                                  VLC_TRUE );
-    add_integer( SOUT_CFG_PREFIX "late", 0, NULL, LATE_TEXT, LATE_LONGTEXT,
-                                 VLC_TRUE );
+    add_suppressed_integer( SOUT_CFG_PREFIX "late" );
     add_bool( SOUT_CFG_PREFIX "raw",  0, NULL, RAW_TEXT, RAW_LONGTEXT,
                                  VLC_TRUE );
 
@@ -114,7 +110,6 @@ static const char *ppsz_sout_options[] = {
     "caching",
     "ttl",
     "group",
-    "late",
     "raw",
     NULL
 };
@@ -137,9 +132,12 @@ typedef struct sout_access_thread_t
     int         i_handle;
 
     int64_t     i_caching;
-    int64_t     i_late;
     int         i_group;
 
+    vlc_mutex_t blocks_lock;
+    block_t     *p_empty_blocks;
+    int         i_empty_depth;
+
 } sout_access_thread_t;
 
 struct sout_access_out_sys_t
@@ -238,6 +236,9 @@ static int Open( vlc_object_t *p_this )
     p_sys->p_thread->b_die  = 0;
     p_sys->p_thread->b_error= 0;
     p_sys->p_thread->p_fifo = block_FifoNew( p_access );
+    p_sys->p_thread->p_empty_blocks = NULL;
+    p_sys->p_thread->i_empty_depth = 0;
+    vlc_mutex_init( p_access, &p_sys->p_thread->blocks_lock );
 
     socket_desc.psz_server_addr = psz_dst_addr;
     socket_desc.i_server_port   = i_dst_port;
@@ -263,9 +264,6 @@ static int Open( vlc_object_t *p_this )
     var_Get( p_access, SOUT_CFG_PREFIX "group", &val );
     p_sys->p_thread->i_group = val.i_int;
 
-    var_Get( p_access, SOUT_CFG_PREFIX "late", &val );
-    p_sys->p_thread->i_late = (int64_t)val.i_int * 1000;
-
     p_sys->i_mtu = socket_desc.i_mtu;
 
 #ifdef WIN32
@@ -326,6 +324,13 @@ static void Close( vlc_object_t * p_this )
     block_FifoRelease( p_sys->p_thread->p_fifo );
 
     if( p_sys->p_buffer ) block_Release( p_sys->p_buffer );
+    while ( p_sys->p_thread->p_empty_blocks != NULL )
+    {
+        block_t *p_next = p_sys->p_thread->p_empty_blocks->p_next;
+        block_Release( p_sys->p_thread->p_empty_blocks );
+        p_sys->p_thread->p_empty_blocks = p_next;
+    }
+    vlc_mutex_destroy( &p_sys->p_thread->blocks_lock );
 
     net_Close( p_sys->p_thread->i_handle );
 
@@ -433,7 +438,34 @@ static block_t *NewUDPPacket( sout_access_out_t *p_access, mtime_t i_dts)
     sout_access_out_sys_t *p_sys = p_access->p_sys;
     block_t *p_buffer;
 
-    p_buffer = block_New( p_access->p_sout, p_sys->i_mtu );
+    vlc_mutex_lock( &p_sys->p_thread->blocks_lock );
+    while ( p_sys->p_thread->i_empty_depth > MAX_EMPTY_BLOCKS )
+    {
+        p_buffer = p_sys->p_thread->p_empty_blocks;
+        p_sys->p_thread->p_empty_blocks =
+                    p_sys->p_thread->p_empty_blocks->p_next;
+        p_sys->p_thread->i_empty_depth--;
+        vlc_mutex_unlock( &p_sys->p_thread->blocks_lock );
+        block_Release( p_buffer );
+        vlc_mutex_lock( &p_sys->p_thread->blocks_lock );
+    }
+    p_buffer = p_sys->p_thread->p_empty_blocks;
+    if ( p_buffer != NULL )
+    {
+        p_sys->p_thread->p_empty_blocks =
+                    p_sys->p_thread->p_empty_blocks->p_next;
+        p_sys->p_thread->i_empty_depth--;
+        vlc_mutex_unlock( &p_sys->p_thread->blocks_lock );
+        p_buffer->p_next = NULL;
+        p_buffer->i_flags = 0;
+        p_buffer = block_Realloc( p_buffer, 0, p_sys->i_mtu );
+    }
+    else
+    {
+        vlc_mutex_unlock( &p_sys->p_thread->blocks_lock );
+        p_buffer = block_New( p_access->p_sout, p_sys->i_mtu );
+    }
+
     p_buffer->i_dts = i_dts;
     p_buffer->i_buffer = 0;
 
@@ -491,36 +523,22 @@ static void ThreadWrite( vlc_object_t *p_this )
                     msg_Dbg( p_thread, "mmh, hole ("I64Fd" > 2s) -> drop",
                              i_date - i_date_last );
 
-                block_Release( p_pk  );
-                i_date_last = i_date;
-                i_dropped_packets++;
-                continue;
-            }
-            else if( i_date - i_date_last < -15000 )
-            {
-                if( !i_dropped_packets )
-                    msg_Dbg( p_thread, "mmh, packets in the past ("I64Fd")"
-                             " -> drop", i_date - i_date_last );
+                vlc_mutex_lock( &p_thread->blocks_lock );
+                p_pk->p_next = p_thread->p_empty_blocks;
+                p_thread->p_empty_blocks = p_pk;
+                p_thread->i_empty_depth++;
+                vlc_mutex_unlock( &p_thread->blocks_lock );
 
-                block_Release( p_pk  );
                 i_date_last = i_date;
                 i_dropped_packets++;
                 continue;
             }
-        }
-
-        i_sent = mdate();
-        if( p_thread->i_late > 0 && i_sent > i_date + p_thread->i_late )
-        {
-            if( !i_dropped_packets )
+            else if( i_date - i_date_last < 0 )
             {
-                msg_Dbg( p_thread, "late packet to send (" I64Fd ") -> drop",
-                         i_sent - i_date );
+                if( !i_dropped_packets )
+                    msg_Dbg( p_thread, "mmh, packets in the past ("I64Fd")",
+                             i_date_last - i_date );
             }
-            block_Release( p_pk  );
-            i_date_last = i_date;
-            i_dropped_packets++;
-            continue;
         }
 
         i_to_send--;
@@ -546,7 +564,12 @@ static void ThreadWrite( vlc_object_t *p_this )
         }
 #endif
 
-        block_Release( p_pk  );
+        vlc_mutex_lock( &p_thread->blocks_lock );
+        p_pk->p_next = p_thread->p_empty_blocks;
+        p_thread->p_empty_blocks = p_pk;
+        p_thread->i_empty_depth++;
+        vlc_mutex_unlock( &p_thread->blocks_lock );
+
         i_date_last = i_date;
     }
 }