mpi: infrastructure to gracefully disable MPI dyn procs

Add ompi_mpi_dynamics_disable() function to disable MPI dynamic
process functionality (i.e., such that if MPI_COMM_SPAWN/etc. are
invoked, you'll get a show_help error explaining that MPI dynamic
process functionality is disabled in this environment -- instead of a
potentially-cryptic network or hardware error).

Fixes #984

ompi/mpi/c/comm_accept.c

@@ -26,8 +26,11 @@
 #include "ompi_config.h"
 #include <stdio.h>
 
+#include "opal/util/show_help.h"
+
 #include "ompi/mpi/c/bindings.h"
 #include "ompi/runtime/params.h"
+#include "ompi/runtime/mpiruntime.h"
 #include "ompi/communicator/communicator.h"
 #include "ompi/errhandler/errhandler.h"
 #include "ompi/info/info.h"
@@ -89,6 +92,10 @@ int MPI_Comm_accept(const char *port_name, MPI_Info info, int root,
         }
     }
 
+    if (!ompi_mpi_dynamics_is_enabled(FUNC_NAME)) {
+        return OMPI_ERRHANDLER_INVOKE(comm, OMPI_ERR_NOT_SUPPORTED, FUNC_NAME);
+    }
+
     /* parse info object. no prefedined values for this function in MPI-2
      * so lets ignore it for the moment.
      * if ( rank == root && MPI_INFO_NULL != info ) {
@@ -107,6 +114,14 @@ int MPI_Comm_accept(const char *port_name, MPI_Info info, int root,
 
     OPAL_CR_EXIT_LIBRARY();
 
+    if (OPAL_ERR_NOT_SUPPORTED == rc) {
+        opal_show_help("help-mpi-api.txt",
+                       "MPI function not supported",
+                       true,
+                       FUNC_NAME,
+                       "Underlying runtime environment does not support accept/connect functionality");
+    }
+
     *newcomm = newcomp;
     OMPI_ERRHANDLER_RETURN(rc, comm, rc, FUNC_NAME );
 }

ompi/mpi/c/comm_connect.c

@@ -26,8 +26,11 @@
 #include "ompi_config.h"
 #include <stdio.h>
 
+#include "opal/util/show_help.h"
+
 #include "ompi/mpi/c/bindings.h"
 #include "ompi/runtime/params.h"
+#include "ompi/runtime/mpiruntime.h"
 #include "ompi/communicator/communicator.h"
 #include "ompi/errhandler/errhandler.h"
 #include "ompi/info/info.h"
@@ -89,6 +92,10 @@ int MPI_Comm_connect(const char *port_name, MPI_Info info, int root,
         }
     }
 
+    if (!ompi_mpi_dynamics_is_enabled(FUNC_NAME)) {
+        return OMPI_ERRHANDLER_INVOKE(comm, OMPI_ERR_NOT_SUPPORTED, FUNC_NAME);
+    }
+
     /* parse info object. No prefedined values for this function in MPI-2,
      * so lets ignore it for the moment.
      *
@@ -109,6 +116,14 @@ int MPI_Comm_connect(const char *port_name, MPI_Info info, int root,
 
     OPAL_CR_EXIT_LIBRARY();
 
+    if (OPAL_ERR_NOT_SUPPORTED == rc) {
+        opal_show_help("help-mpi-api.txt",
+                       "MPI function not supported",
+                       true,
+                       FUNC_NAME,
+                       "Underlying runtime environment does not support accept/connect functionality");
+    }
+
     *newcomm = newcomp;
     OMPI_ERRHANDLER_RETURN(rc, comm, rc, FUNC_NAME);
 }

ompi/mpi/c/comm_join.c

@@ -37,8 +37,11 @@
 #include <netinet/in.h>
 #endif
 
+#include "opal/util/show_help.h"
+
 #include "ompi/mpi/c/bindings.h"
 #include "ompi/runtime/params.h"
+#include "ompi/runtime/mpiruntime.h"
 #include "ompi/communicator/communicator.h"
 #include "ompi/errhandler/errhandler.h"
 #include "ompi/dpm/dpm.h"
@@ -75,6 +78,11 @@ int MPI_Comm_join(int fd, MPI_Comm *intercomm)
         }
     }
 
+    if (!ompi_mpi_dynamics_is_enabled(FUNC_NAME)) {
+        return OMPI_ERRHANDLER_INVOKE(MPI_COMM_WORLD, OMPI_ERR_NOT_SUPPORTED,
+                                      FUNC_NAME);
+    }
+
     OPAL_CR_ENTER_LIBRARY();
 
     /* send my process name */
@@ -114,8 +122,7 @@ int MPI_Comm_join(int fd, MPI_Comm *intercomm)
     if (send_first) {
         /* open a port */
         if (OMPI_SUCCESS != (rc = ompi_dpm_open_port(port_name))) {
-            OPAL_CR_EXIT_LIBRARY();
-            return rc;
+            goto error;
         }
         llen   = (uint32_t)(strlen(port_name)+1);
         len    = htonl(llen);
@@ -133,6 +140,18 @@ int MPI_Comm_join(int fd, MPI_Comm *intercomm)
     OPAL_CR_EXIT_LIBRARY();
 
     *intercomm = newcomp;
+
+ error:
+    OPAL_CR_EXIT_LIBRARY();
+
+    if (OPAL_ERR_NOT_SUPPORTED == rc) {
+        opal_show_help("help-mpi-api.txt",
+                       "MPI function not supported",
+                       true,
+                       FUNC_NAME,
+                       "Underlying runtime environment does not support join functionality");
+    }
+
     OMPI_ERRHANDLER_RETURN (rc, MPI_COMM_SELF, rc, FUNC_NAME);
 }
 

ompi/mpi/c/comm_spawn.c

@@ -26,9 +26,12 @@
 #include "ompi_config.h"
 #include <stdio.h>
 
+#include "opal/util/show_help.h"
+
 #include "ompi/info/info.h"
 #include "ompi/mpi/c/bindings.h"
 #include "ompi/runtime/params.h"
+#include "ompi/runtime/mpiruntime.h"
 #include "ompi/communicator/communicator.h"
 #include "ompi/errhandler/errhandler.h"
 #include "ompi/dpm/dpm.h"
@@ -97,6 +100,10 @@ int MPI_Comm_spawn(const char *command, char *argv[], int maxprocs, MPI_Info inf
         }
     }
 
+    if (!ompi_mpi_dynamics_is_enabled(FUNC_NAME)) {
+        return OMPI_ERRHANDLER_INVOKE(comm, OMPI_ERR_NOT_SUPPORTED, FUNC_NAME);
+    }
+
     /* initialize the port name to avoid problems */
     memset(port_name, 0, MPI_MAX_PORT_NAME);
 
@@ -132,6 +139,14 @@ int MPI_Comm_spawn(const char *command, char *argv[], int maxprocs, MPI_Info inf
     }
 
 error:
+    if (OPAL_ERR_NOT_SUPPORTED == rc) {
+        opal_show_help("help-mpi-api.txt",
+                       "MPI function not supported",
+                       true,
+                       FUNC_NAME,
+                       "Underlying runtime environment does not support spawn functionality");
+    }
+
     /* close the port */
     if (rank == root && !non_mpi) {
         ompi_dpm_close_port(port_name);

ompi/mpi/c/comm_spawn_multiple.c

@@ -26,8 +26,11 @@
 #include "ompi_config.h"
 #include <stdio.h>
 
+#include "opal/util/show_help.h"
+
 #include "ompi/mpi/c/bindings.h"
 #include "ompi/runtime/params.h"
+#include "ompi/runtime/mpiruntime.h"
 #include "ompi/communicator/communicator.h"
 #include "ompi/errhandler/errhandler.h"
 #include "ompi/info/info.h"
@@ -130,6 +133,10 @@ int MPI_Comm_spawn_multiple(int count, char *array_of_commands[], char **array_o
         }
     }
 
+    if (!ompi_mpi_dynamics_is_enabled(FUNC_NAME)) {
+        return OMPI_ERRHANDLER_INVOKE(comm, OMPI_ERR_NOT_SUPPORTED, FUNC_NAME);
+    }
+
     if (rank == root) {
         if (MPI_INFO_NULL == array_of_info[0]) {
             non_mpi = false;
@@ -173,6 +180,14 @@ int MPI_Comm_spawn_multiple(int count, char *array_of_commands[], char **array_o
     }
 
 error:
+    if (OPAL_ERR_NOT_SUPPORTED == rc) {
+        opal_show_help("help-mpi-api.txt",
+                       "MPI function not supported",
+                       true,
+                       FUNC_NAME,
+                       "Underlying runtime environment does not support spawn functionality");
+    }
+
     /* close the port */
     if (rank == root && !non_mpi) {
         ompi_dpm_close_port(port_name);

ompi/mpi/c/lookup_name.c

@@ -27,6 +27,7 @@
 
 #include "opal/class/opal_list.h"
 #include "opal/mca/pmix/pmix.h"
+#include "opal/util/show_help.h"
 
 #include "ompi/mpi/c/bindings.h"
 #include "ompi/runtime/params.h"
@@ -69,6 +70,17 @@ int MPI_Lookup_name(const char *service_name, MPI_Info info, char *port_name)
         }
     }
 
+    if (NULL == opal_pmix.lookup) {
+        opal_show_help("help-mpi-api.txt",
+                       "MPI function not supported",
+                       true,
+                       FUNC_NAME,
+                       "Underlying runtime environment does not support name lookup functionality");
+        return OMPI_ERRHANDLER_INVOKE(MPI_COMM_WORLD,
+                                      OMPI_ERR_NOT_SUPPORTED,
+                                      FUNC_NAME);
+    }
+
     OPAL_CR_ENTER_LIBRARY();
 
     OBJ_CONSTRUCT(&pinfo, opal_list_t);
@@ -111,9 +123,19 @@ int MPI_Lookup_name(const char *service_name, MPI_Info info, char *port_name)
     if (OPAL_SUCCESS != ret ||
         OPAL_STRING != pdat->value.type ||
         NULL == pdat->value.data.string) {
+        if (OPAL_ERR_NOT_SUPPORTED == ret) {
+            ret = OMPI_ERR_NOT_SUPPORTED;
+            opal_show_help("help-mpi-api.txt",
+                           "MPI function not supported",
+                           true,
+                           FUNC_NAME,
+                           "Underlying runtime environment does not support name lookup functionality");
+        } else {
+            ret = MPI_ERR_NAME;
+        }
+
         OPAL_CR_EXIT_LIBRARY();
-        return OMPI_ERRHANDLER_INVOKE(MPI_COMM_WORLD, MPI_ERR_NAME,
-                                      FUNC_NAME);
+        return OMPI_ERRHANDLER_INVOKE(MPI_COMM_WORLD, ret, FUNC_NAME);
     }
 
     strncpy ( port_name, pdat->value.data.string, MPI_MAX_PORT_NAME );

ompi/mpi/c/publish_name.c

@@ -13,7 +13,6 @@
  * Copyright (c) 2013      Los Alamos National Security, LLC.  All rights
  *                         reserved.
  * Copyright (c) 2015      Intel, Inc. All rights reserved.
- *
  * Copyright (c) 2015      Research Organization for Information Science
  *                         and Technology (RIST). All rights reserved.
  * Copyright (c) 2015 Cisco Systems, Inc.  All rights reserved.
@@ -28,6 +27,7 @@
 
 #include "opal/class/opal_list.h"
 #include "opal/mca/pmix/pmix.h"
+#include "opal/util/show_help.h"
 
 #include "ompi/mpi/c/bindings.h"
 #include "ompi/runtime/params.h"
@@ -71,6 +71,17 @@ int MPI_Publish_name(const char *service_name, MPI_Info info,
         }
     }
 
+    if (NULL == opal_pmix.publish) {
+        opal_show_help("help-mpi-api.txt",
+                       "MPI function not supported",
+                       true,
+                       FUNC_NAME,
+                       "Underlying runtime environment does not support name publishing functionality");
+        return OMPI_ERRHANDLER_INVOKE(MPI_COMM_WORLD,
+                                      OMPI_ERR_NOT_SUPPORTED,
+                                        FUNC_NAME);
+    }
+
     OPAL_CR_ENTER_LIBRARY();
     OBJ_CONSTRUCT(&values, opal_list_t);
 
@@ -149,15 +160,20 @@ int MPI_Publish_name(const char *service_name, MPI_Info info,
     if ( OPAL_SUCCESS != rc ) {
         if (OPAL_EXISTS == rc) {
             /* already exists - can't publish it */
-            return OMPI_ERRHANDLER_INVOKE(MPI_COMM_WORLD, MPI_ERR_FILE_EXISTS,
-                                          FUNC_NAME);
+            rc = MPI_ERR_FILE_EXISTS;
+        } else if (OPAL_ERR_NOT_SUPPORTED == rc) {
+            /* this PMIX environment doesn't support publishing */
+            rc = OMPI_ERR_NOT_SUPPORTED;
+            opal_show_help("help-mpi-api.txt",
+                           "MPI function not supported",
+                           true,
+                           FUNC_NAME,
+                           "Underlying runtime environment does not support name publishing functionality");
+        } else {
+            rc = MPI_ERR_INTERN;
         }
 
-        /* none of the MPI-specific errors occurred - must be some
-         * kind of internal error
-         */
-        return OMPI_ERRHANDLER_INVOKE(MPI_COMM_WORLD, MPI_ERR_INTERN,
-                                      FUNC_NAME);
+        return OMPI_ERRHANDLER_INVOKE(MPI_COMM_WORLD, rc, FUNC_NAME);
     }
 
     return MPI_SUCCESS;

ompi/mpi/c/unpublish_name.c

@@ -15,6 +15,7 @@
  * Copyright (c) 2015      Intel, Inc. All rights reserved.
  * Copyright (c) 2015      Research Organization for Information Science
  *                         and Technology (RIST). All rights reserved.
+ * Copyright (c) 2015 Cisco Systems, Inc.  All rights reserved.
  * $COPYRIGHT$
  *
  * Additional copyrights may follow
@@ -27,6 +28,7 @@
 #include "opal/class/opal_list.h"
 #include "opal/mca/pmix/pmix.h"
 #include "opal/util/argv.h"
+#include "opal/util/show_help.h"
 
 #include "ompi/mpi/c/bindings.h"
 #include "ompi/runtime/params.h"
@@ -71,6 +73,17 @@ int MPI_Unpublish_name(const char *service_name, MPI_Info info,
         }
     }
 
+    if (NULL == opal_pmix.publish) {
+        opal_show_help("help-mpi-api.txt",
+                       "MPI function not supported",
+                       true,
+                       FUNC_NAME,
+                       "Underlying runtime environment does not support name publishing functionality");
+        return OMPI_ERRHANDLER_INVOKE(MPI_COMM_WORLD,
+                                      OMPI_ERR_NOT_SUPPORTED,
+                                      FUNC_NAME);
+    }
+
     OPAL_CR_ENTER_LIBRARY();
     OBJ_CONSTRUCT(&pinfo, opal_list_t);
 
@@ -110,23 +123,24 @@ int MPI_Unpublish_name(const char *service_name, MPI_Info info,
     if ( OPAL_SUCCESS != rc ) {
         if (OPAL_ERR_NOT_FOUND == rc) {
             /* service couldn't be found */
-            OPAL_CR_EXIT_LIBRARY();
-            return OMPI_ERRHANDLER_INVOKE(MPI_COMM_WORLD, MPI_ERR_SERVICE,
-                                          FUNC_NAME);
-        }
-        if (OPAL_ERR_PERM == rc) {
+            rc = MPI_ERR_SERVICE;
+        } else if (OPAL_ERR_PERM == rc) {
             /* this process didn't own the specified service */
-            OPAL_CR_EXIT_LIBRARY();
-            return OMPI_ERRHANDLER_INVOKE(MPI_COMM_WORLD, MPI_ERR_ACCESS,
-                                          FUNC_NAME);
+            rc = MPI_ERR_ACCESS;
+        } else if (OPAL_ERR_NOT_SUPPORTED == rc) {
+            /* this PMIX environment doesn't support publishing */
+            rc = OMPI_ERR_NOT_SUPPORTED;
+            opal_show_help("help-mpi-api.txt",
+                           "MPI function not supported",
+                           true,
+                           FUNC_NAME,
+                           "Underlying runtime environment does not support name publishing functionality");
+        } else {
+            rc = MPI_ERR_INTERN;
         }
 
-        /* none of the MPI-specific errors occurred - must be some
-         * kind of internal error
-         */
         OPAL_CR_EXIT_LIBRARY();
-        return OMPI_ERRHANDLER_INVOKE(MPI_COMM_WORLD, MPI_ERR_INTERN,
-                                      FUNC_NAME);
+        return OMPI_ERRHANDLER_INVOKE(MPI_COMM_WORLD, rc, FUNC_NAME);
     }
 
     OPAL_CR_EXIT_LIBRARY();

ompi/mpi/help-mpi-api.txt

@@ -2,7 +2,7 @@
 #
 # Copyright (c) 2006      High Performance Computing Center Stuttgart,
 #                         University of Stuttgart.  All rights reserved.
-# Copyright (c) 2006-2008 Cisco Systems, Inc.  All rights reserved.
+# Copyright (c) 2006-2015 Cisco Systems, Inc.  All rights reserved.
 # $COPYRIGHT$
 #
 # Additional copyrights may follow
@@ -12,8 +12,10 @@
 # This is the US/English general help file for Open MPI.
 #
 [mpi-function-after-finalize]
-Calling any MPI-function after calling MPI_Finalize is erroneous.
-The only exceptions are MPI_Initialized, MPI_Finalized and MPI_Get_version.
+Calling most MPI functions after calling MPI_Finalize is erroneous.
+
+There are a small number of exceptions, such as MPI_Initialized,
+MPI_Finalized, and MPI_Get_version.
 #
 [mpi-initialize-twice]
 Calling MPI_Init or MPI_Init_thread twice is erroneous.
@@ -25,3 +27,10 @@ with errorcode %d.
 NOTE: invoking MPI_ABORT causes Open MPI to kill all MPI processes.
 You may or may not see output from other processes, depending on
 exactly when Open MPI kills them.
+#
+[MPI function not supported]
+Your application has invoked an MPI function that is not supported in
+this environment.
+
+  MPI function: %s
+  Reason:       %s

ompi/runtime/Makefile.am

@@ -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) 2006-2009 Cisco Systems, Inc.  All rights reserved.
+# Copyright (c) 2006-2015 Cisco Systems, Inc.  All rights reserved.
 # Copyright (c) 2014      Intel, Inc. All rights reserved.
 # $COPYRIGHT$
 #
@@ -30,6 +30,7 @@ headers += \
 
 libmpi_la_SOURCES += \
         runtime/ompi_mpi_abort.c \
+        runtime/ompi_mpi_dynamics.c \
         runtime/ompi_mpi_init.c \
         runtime/ompi_mpi_finalize.c \
         runtime/ompi_mpi_params.c \

ompi/runtime/mpiruntime.h

@@ -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) 2006-2012 Cisco Systems, Inc.  All rights reserved.
+ * Copyright (c) 2006-2015 Cisco Systems, Inc.  All rights reserved.
  * Copyright (c) 2007      Los Alamos National Security, LLC.  All rights
  *                         reserved.
  * Copyright (c) 2008      Sun Microsystems, Inc.  All rights reserved.
@@ -191,6 +191,37 @@ OMPI_DECLSPEC int ompi_mpi_abort(struct ompi_communicator_t* comm,
  */
 int ompi_init_preconnect_mpi(void);
 
+/**
+ * Called to disable MPI dynamic process support.  It should be called
+ * by transports and/or environments where MPI dynamic process
+ * functionality cannot be supported, and provide a string indicating
+ * why the functionality is disabled (because it will be shown in a
+ * user help message).  For example, "<TRANSPORT> does not support MPI
+ * dynamic process functionality."
+ *
+ * This first-order functionality is fairly coarse-grained and simple:
+ * it presents a friendly show-help message to tell users why their
+ * MPI dynamic process functionality failed (vs. a potentially-cryptic
+ * network or hardware failure message).
+ *
+ * Someone may choose to implement a more fine-grained approach in the
+ * future.
+ */
+void ompi_mpi_dynamics_disable(const char *msg);
+
+/**
+ * Called by the MPI dynamic process functions (e.g., MPI_Comm_spawn)
+ * to see if MPI dynamic process support is enabled.  If it's not,
+ * this function will opal_show_help() a message and return false.
+ */
+bool ompi_mpi_dynamics_is_enabled(const char *function);
+
+/**
+ * Clean up memory / resources by the MPI dynamics process
+ * functionality checker
+ */
+void ompi_mpi_dynamics_finalize(void);
+
 END_C_DECLS
 
 #endif /* OMPI_MPI_MPIRUNTIME_H */

ompi/runtime/ompi_mpi_dynamics.c

@@ -0,0 +1,64 @@
+/* -*- Mode: C; c-basic-offset:4 ; indent-tabs-mode:nil -*- */
+/*
+ * Copyright (c) 2004-2005 The Trustees of Indiana University and Indiana
+ *                         University Research and Technology
+ *                         Corporation.  All rights reserved.
+ * Copyright (c) 2004-2006 The University of Tennessee and The University
+ *                         of Tennessee Research Foundation.  All rights
+ *                         reserved.
+ * Copyright (c) 2004-2005 High Performance Computing Center Stuttgart,
+ *                         University of Stuttgart.  All rights reserved.
+ * Copyright (c) 2004-2005 The Regents of the University of California.
+ *                         All rights reserved.
+ * Copyright (c) 2006-2015 Cisco Systems, Inc.  All rights reserved.
+ * Copyright (c) 2007-2015 Los Alamos National Security, LLC.  All rights
+ *                         reserved.
+ * Copyright (c) 2013      NVIDIA Corporation.  All rights reserved.
+ * Copyright (c) 2013-2014 Intel, Inc. All rights reserved
+ * $COPYRIGHT$
+ *
+ * Additional copyrights may follow
+ *
+ * $HEADER$
+ */
+
+#include "ompi_config.h"
+
+#include "opal/util/show_help.h"
+
+#include "ompi/runtime/params.h"
+#include "ompi/runtime/mpiruntime.h"
+
+static char *ompi_mpi_dynamics_disabled_msg = "Enabled";
+
+
+void ompi_mpi_dynamics_disable(const char *msg)
+{
+    assert(msg);
+
+    ompi_mpi_dynamics_enabled = false;
+    ompi_mpi_dynamics_disabled_msg = strdup(msg);
+}
+
+bool ompi_mpi_dynamics_is_enabled(const char *function)
+{
+    if (ompi_mpi_dynamics_enabled) {
+        return true;
+    }
+
+    opal_show_help("help-mpi-api.txt",
+                   "MPI function not supported",
+                   true,
+                   function,
+                   ompi_mpi_dynamics_disabled_msg);
+    return false;
+}
+
+void ompi_mpi_dynamics_finalize(void)
+{
+    // If dynamics were disabled, then we have a message to free
+    if (!ompi_mpi_dynamics_enabled) {
+        free(ompi_mpi_dynamics_disabled_msg);
+        ompi_mpi_dynamics_disabled_msg = NULL;
+    }
+}

ompi/runtime/ompi_mpi_finalize.c

@@ -10,7 +10,7 @@
  *                         University of Stuttgart.  All rights reserved.
  * Copyright (c) 2004-2005 The Regents of the University of California.
  *                         All rights reserved.
- * Copyright (c) 2006-2013 Cisco Systems, Inc.  All rights reserved.
+ * Copyright (c) 2006-2015 Cisco Systems, Inc.  All rights reserved.
  * Copyright (c) 2006-2014 Los Alamos National Security, LLC.  All rights
  *                         reserved.
  * Copyright (c) 2006      University of Houston. All rights reserved.
@@ -423,6 +423,10 @@ int ompi_mpi_finalize(void)
         ompi_mpi_main_thread = NULL;
     }
 
+    /* Clean up memory/resources from the MPI dynamic process
+       functionality checker */
+    ompi_mpi_dynamics_finalize();
+
     /* Leave the RTE */
 
     if (OMPI_SUCCESS != (ret = ompi_rte_finalize())) {

ompi/runtime/ompi_mpi_params.c

@@ -10,7 +10,7 @@
  *                         University of Stuttgart.  All rights reserved.
  * Copyright (c) 2004-2005 The Regents of the University of California.
  *                         All rights reserved.
- * Copyright (c) 2006-2009 Cisco Systems, Inc.  All rights reserved.
+ * Copyright (c) 2006-2015 Cisco Systems, Inc.  All rights reserved.
  * Copyright (c) 2007-2015 Los Alamos National Security, LLC.  All rights
  *                         reserved.
  * Copyright (c) 2013      NVIDIA Corporation.  All rights reserved.
@@ -65,6 +65,7 @@ char *ompi_mpi_show_mca_params_string = NULL;
 bool ompi_mpi_have_sparse_group_storage = !!(OMPI_GROUP_SPARSE);
 bool ompi_mpi_preconnect_mpi = false;
 uint32_t ompi_add_procs_cutoff = 1024;
+bool ompi_mpi_dynamics_enabled = true;
 
 static bool show_default_mca_params = false;
 static bool show_file_mca_params = false;
@@ -299,6 +300,14 @@ int ompi_mpi_register_params(void)
                                   &ompi_add_procs_cutoff);
 
 
+    ompi_mpi_dynamics_enabled = true;
+    (void) mca_base_var_register("ompi", "mpi", NULL, "dynamics_enabled",
+                                 "Is the MPI dynamic process functionality enabled (e.g., MPI_COMM_SPAWN)?  Default is yes, but certain transports and/or environments may disable it.",
+                                 MCA_BASE_VAR_TYPE_BOOL, NULL, 0, 0,
+                                 OPAL_INFO_LVL_4,
+                                 MCA_BASE_VAR_SCOPE_READONLY,
+                                 &ompi_mpi_dynamics_enabled);
+
     return OMPI_SUCCESS;
 }
 

ompi/runtime/params.h

@@ -12,7 +12,7 @@
  *                         All rights reserved.
  * Copyright (c) 2007-2015 Los Alamos National Security, LLC.  All rights
  *                         reserved.
- * Copyright (c) 2006-2009 Cisco Systems, Inc.  All rights reserved.
+ * Copyright (c) 2006-2015 Cisco Systems, Inc.  All rights reserved.
  * Copyright (c) 2013      NVIDIA Corporation.  All rights reserved.
  * Copyright (c) 2013      Intel, Inc. All rights reserved
  * $COPYRIGHT$
@@ -134,6 +134,12 @@ OMPI_DECLSPEC extern uint32_t ompi_direct_modex_cutoff;
  */
 OMPI_DECLSPEC extern uint32_t ompi_add_procs_cutoff;
 
+/**
+ * Whether anything in the code base has disabled MPI dynamic process
+ * functionality or not
+ */
+OMPI_DECLSPEC extern bool ompi_mpi_dynamics_enabled;
+
 /**
  * Register MCA parameters used by the MPI layer.
  *