Added round trip time contraint to the SDP program, this parameter

[simgrid.git] / src / gras / Transport / rl_transport.c

diff --git a/src/gras/Transport/rl_transport.c b/src/gras/Transport/rl_transport.c
index 6d65d78..7d7c7a4 100644 (file)
--- a/src/gras/Transport/rl_transport.c
+++ b/src/gras/Transport/rl_transport.c
@@ -12,6 +12,9 @@
 #include "gras/Transport/transport_private.h"
 XBT_LOG_EXTERNAL_DEFAULT_CATEGORY(gras_trp);
 
+/* check transport_private.h for an explanation of this variable */
+gras_socket_t _gras_lastly_selected_socket = NULL;
+
 /**
  * gras_trp_select:
  *
@@ -37,29 +40,37 @@ gras_socket_t gras_trp_select(double timeout) {
      with this tiny optimisation on BillWare */
   fd_set FDS;
   int ready; /* return of select: number of socket ready to be serviced */
-  int fd_setsize; /* FD_SETSIZE not always defined. Get this portably */
+  static int fd_setsize=-1; /* FD_SETSIZE not always defined. Get this portably */
 
   gras_socket_t sock_iter; /* iterating over all sockets */
   int cursor;              /* iterating over all sockets */
 
-   
-  /* Compute FD_SETSIZE */
+  /* Check whether there is more data to read from the socket we selected last time.
+     This can happen with tcp buffered sockets since we try to get as much data as we can for them */
+  if (_gras_lastly_selected_socket && _gras_lastly_selected_socket->moredata) {
+     VERB0("Returning _gras_lastly_selected_socket since there is more data on it");
+     return _gras_lastly_selected_socket;
+  }
+  
+  /* Compute FD_SETSIZE on need */
+  if (fd_setsize < 0) {        
 #ifdef HAVE_SYSCONF
-   fd_setsize = sysconf( _SC_OPEN_MAX );
+     fd_setsize = sysconf( _SC_OPEN_MAX );
 #else
 #  ifdef HAVE_GETDTABLESIZE 
-   fd_setsize = getdtablesize();
+     fd_setsize = getdtablesize();
 #  else
-   fd_setsize = FD_SETSIZE;
+     fd_setsize = FD_SETSIZE;
 #  endif /* !USE_SYSCONF */
 #endif
+  }
 
   while (done == -1) {
     if (timeout > 0) { /* did we timeout already? */
       now = gras_os_time();
       DEBUG2("wakeup=%f now=%f",wakeup, now);
       if (now == -1 || now >= wakeup) {
-       /* didn't find anything */
+       /* didn't find anything; no need to update _gras_lastly_selected_socket since its moredata is 0 (or we would have returned it directly) */
        THROW1(timeout_error,0,
               "Timeout (%f) elapsed with selecting for incomming connexions",
               timeout);
@@ -78,6 +89,9 @@ gras_socket_t gras_trp_select(double timeout) {
 #ifndef HAVE_WINSOCK_H
        if (max_fds < sock_iter->sd)
          max_fds = sock_iter->sd;
+#else
+      max_fds = 0;
+
 #endif
        FD_SET(sock_iter->sd, &FDS);
       } else {
@@ -182,12 +196,14 @@ gras_socket_t gras_trp_select(double timeout) {
         } else { 
           /* Got a suited socket ! */
           XBT_OUT;
+          _gras_lastly_selected_socket = sock_iter;
           return sock_iter;
         }
 
        } else {
         /* This is a file socket. Cannot recv() on it, but it must be alive */
           XBT_OUT;
+          _gras_lastly_selected_socket = sock_iter;
           return sock_iter;
        }