Index: ompi/runtime/params.h
===================================================================
--- ompi/runtime/params.h	(revision 21776)
+++ ompi/runtime/params.h	(working copy)
@@ -11,7 +11,7 @@
  *                         All rights reserved.
  * Copyright (c) 2007      Los Alamos National Security, LLC.  All rights
  *                         reserved. 
- * Copyright (c) 2006-2008 Cisco Systems, Inc.  All rights reserved.
+ * Copyright (c) 2006-2009 Cisco Systems, Inc.  All rights reserved.
  * $COPYRIGHT$
  * 
  * Additional copyrights may follow
@@ -146,6 +146,15 @@
 OMPI_DECLSPEC extern bool ompi_use_sparse_group_storage;
 
 /**
+ * Indicates whether Open MPI will use MCA_PML_BASE_SEND_STANDARD or 
+ * MCA_PML_BASE_SEND_SYNCHRONOUS.
+ * -mca standard_send_pml_flag [val]
+ * [val] >=1  = MCA_PML_BASE_SEND_SYNCHRONOUS
+ * [val] <=0  = MCA_PML_BASE_SEND_STANDARD
+ */
+OMPI_DECLSPEC extern int ompi_mpi_std_send_pml_flags;
+
+/**
  * Register MCA parameters used by the MPI layer.
  *
  * @returns OMPI_SUCCESS
Index: ompi/runtime/ompi_mpi_params.c
===================================================================
--- ompi/runtime/ompi_mpi_params.c	(revision 21776)
+++ ompi/runtime/ompi_mpi_params.c	(working copy)
@@ -9,7 +9,7 @@
  *                         University of Stuttgart.  All rights reserved.
  * Copyright (c) 2004-2005 The Regents of the University of California.
  *                         All rights reserved.
- * Copyright (c) 2006-2008 Cisco Systems, Inc.  All rights reserved.
+ * Copyright (c) 2006-2009 Cisco Systems, Inc.  All rights reserved.
  * Copyright (c) 2007      Los Alamos National Security, LLC.  All rights
  *                         reserved. 
  * $COPYRIGHT$
@@ -32,6 +32,7 @@
 #include "orte/util/show_help.h"
 #include "opal/mca/base/mca_base_param.h"
 #include "opal/util/argv.h"
+#include "ompi/mca/pml/pml.h"
 
 /*
  * Global variables
@@ -57,6 +58,7 @@
 bool ompi_mpi_leave_pinned_pipeline = false;
 bool ompi_have_sparse_group_storage = OPAL_INT_TO_BOOL(OMPI_GROUP_SPARSE);
 bool ompi_use_sparse_group_storage = OPAL_INT_TO_BOOL(OMPI_GROUP_SPARSE);
+int ompi_mpi_std_send_pml_flags = MCA_PML_BASE_SEND_STANDARD;
 
 static bool show_default_mca_params = false;
 static bool show_file_mca_params = false;
@@ -288,6 +290,13 @@
             ompi_use_sparse_group_storage = false;
         }
     }
+    
+    mca_base_param_reg_int_name("mpi", "force_sync_sends",
+                                "If true (nonzero), Open MPI will silently convert all MPI_SENDs, MPI_ISENDs, MPI_SEND_INITs, and MPI_SENDRECVs to use synchronous mode sends rather than standard mode sends (default: 0/standard mode sends).",
+                                false, false, 0, &value);
+    if (0 != value) {
+        ompi_mpi_std_send_pml_flags = MCA_PML_BASE_SEND_SYNCHRONOUS;   
+    }
 
     /* The ddt engine has a few parameters */
     return ompi_ddt_register_params();
Index: ompi/mpi/c/send.c
===================================================================
--- ompi/mpi/c/send.c	(revision 21776)
+++ ompi/mpi/c/send.c	(working copy)
@@ -9,6 +9,7 @@
  *                         University of Stuttgart.  All rights reserved.
  * Copyright (c) 2004-2005 The Regents of the University of California.
  *                         All rights reserved.
+ * Copyright (c) 2009      Cisco Systems, Inc.  All rights reserved.
  * $COPYRIGHT$
  * 
  * Additional copyrights may follow
@@ -69,6 +70,7 @@
 
     OPAL_CR_ENTER_LIBRARY();
 
-    rc = MCA_PML_CALL(send(buf, count, type, dest, tag, MCA_PML_BASE_SEND_STANDARD, comm));
+    rc = MCA_PML_CALL(send(buf, count, type, dest, tag, 
+                           ompi_mpi_std_send_pml_flags, comm));
     OMPI_ERRHANDLER_RETURN(rc, comm, rc, FUNC_NAME);
 }
Index: ompi/mpi/c/send_init.c
===================================================================
--- ompi/mpi/c/send_init.c	(revision 21776)
+++ ompi/mpi/c/send_init.c	(working copy)
@@ -9,7 +9,7 @@
  *                         University of Stuttgart.  All rights reserved.
  * Copyright (c) 2004-2005 The Regents of the University of California.
  *                         All rights reserved.
- * Copyright (c) 2006      Cisco Systems, Inc.  All rights reserved.
+ * Copyright (c) 2006-2009 Cisco Systems, Inc.  All rights reserved.
  * $COPYRIGHT$
  * 
  * Additional copyrights may follow
@@ -85,7 +85,8 @@
     /*
      * Here, we just initialize the request -- memchecker should set the buffer in MPI_Start.
      */
-    rc = MCA_PML_CALL(isend_init(buf,count,type,dest,tag,MCA_PML_BASE_SEND_STANDARD,comm,request));
+    rc = MCA_PML_CALL(isend_init(buf,count,type,dest,tag,
+                                 ompi_mpi_std_send_pml_flags, comm,request));
     OMPI_ERRHANDLER_RETURN(rc, comm, rc, FUNC_NAME);
 }
 
Index: ompi/mpi/c/sendrecv.c
===================================================================
--- ompi/mpi/c/sendrecv.c	(revision 21776)
+++ ompi/mpi/c/sendrecv.c	(working copy)
@@ -9,6 +9,7 @@
  *                         University of Stuttgart.  All rights reserved.
  * Copyright (c) 2004-2005 The Regents of the University of California.
  *                         All rights reserved.
+ * Copyright (c) 2009      Cisco Systems, Inc.  All rights reserved.
  * $COPYRIGHT$
  * 
  * Additional copyrights may follow
@@ -79,7 +80,7 @@
 
     if (dest != MPI_PROC_NULL) { /* send */
         rc = MCA_PML_CALL(send(sendbuf, sendcount, sendtype, dest,
-                               sendtag, MCA_PML_BASE_SEND_STANDARD, comm));
+                               sendtag, ompi_mpi_std_send_pml_flags, comm));
         OMPI_ERRHANDLER_CHECK(rc, comm, rc, FUNC_NAME);
     }
 
Index: ompi/mpi/c/isend.c
===================================================================
--- ompi/mpi/c/isend.c	(revision 21776)
+++ ompi/mpi/c/isend.c	(working copy)
@@ -9,7 +9,7 @@
  *                         University of Stuttgart.  All rights reserved.
  * Copyright (c) 2004-2005 The Regents of the University of California.
  *                         All rights reserved.
- * Copyright (c) 2006-2007 Cisco Systems, Inc.  All rights reserved.
+ * Copyright (c) 2006-2009 Cisco Systems, Inc.  All rights reserved.
  * $COPYRIGHT$
  * 
  * Additional copyrights may follow
@@ -78,7 +78,8 @@
     MEMCHECKER (
         memchecker_call(&opal_memchecker_base_mem_noaccess, buf, count, type);
     );
-    rc = MCA_PML_CALL(isend(buf,count,type,dest,tag,MCA_PML_BASE_SEND_STANDARD,comm,request));
+    rc = MCA_PML_CALL(isend(buf,count,type,dest,tag,
+                            ompi_mpi_std_send_pml_flags, comm, request));
     OMPI_ERRHANDLER_RETURN(rc, comm, rc, FUNC_NAME);
 }
 
Index: NEWS
===================================================================
--- NEWS	(revision 21776)
+++ NEWS	(working copy)
@@ -8,7 +8,7 @@
                         University of Stuttgart.  All rights reserved.
 Copyright (c) 2004-2006 The Regents of the University of California.
                         All rights reserved.
-Copyright (c) 2006-2008 Cisco Systems, Inc.  All rights reserved.
+Copyright (c) 2006-2009 Cisco Systems, Inc.  All rights reserved.
 Copyright (c) 2006      Voltaire, Inc. All rights reserved.
 Copyright (c) 2006      Sun Microsystems, Inc.  All rights reserved.
                         Use is subject to license terms.
@@ -33,6 +33,11 @@
   those symbols being hidden.  This appears to mainly solve the
   problem of applications attempting to use different versions of
   libltdl from that used to build Open MPI.
+- Add new MCA parameter: mpi_force_sync_sends.  If true (nonzero),
+  Open MPI will silently convert all MPI_SENDs, MPI_ISENDs,
+  MPI_SEND_INITs, and MPI_SENDRECVs to use synchronous mode sends
+  rather than standard mode sends; handy for ensuring your MPI
+  application doesn't rely on MPI-level buffering.
 
 
 1.3.3