A complete overhaul of the HAN code.

Among many other things:
- Fix an imbalance bug in MPI_allgather
- Accept more human readable configuration files. We can now specify
  the collective by name instead of a magic number, and the component
  we want to use also by name.
- Add the capability to have optional arguments in the collective
  communication configuration file. Right now the capability exists
  for segment lengths, but is yet to be connected with the algorithms.
- Redo the initialization of all HAN collectives.

Cleanup the fallback collective support.
- In case the module is unable to deliver the expected result, it will fallback
  executing the collective operation on another collective component. This change
  make the support for this fallback simpler to use.
- Implement a fallback allowing a HAN module to remove itself as
  potential active collective module, and instead fallback to the
  next module in line.
- Completely disable the HAN modules on error. From the moment an error is
  encountered they remove themselves from the communicator, and in case some
  other modules calls them simply behave as a pass-through.

Communicator: provide ompi_comm_split_with_info to split and provide info at the same time
Add ompi_comm_coll_preference info key to control collective component selection

COLL HAN: use info keys instead of component-level variable to communicate topology level between abstraction layers
- The info value is a comma-separated list of entries, which are chosen with
  decreasing priorities. This overrides the priority of the component,
  unless the component has disqualified itself.
  An entry prefixed with ^ starts the ignore-list. Any entry following this
  character will be ingnored during the collective component selection for the
  communicator.
  Example: "sm,libnbc,^han,adapt" gives sm the highest preference, followed
  by libnbc. The components han and adapt are ignored in the selection process.
- Allocate a temporary buffer for all lower-level leaders (length 2 segments)
- Fix the handling of MPI_IN_PLACE for gather and scatter.

COLL HAN: Fix topology handling
 - HAN should not rely on node names to determine the ordering of ranks.
   Instead, use the node leaders as identifiers and short-cut if the
   node-leaders agree that ranks are consecutive. Also, error out if
   the rank distribution is imbalanced for now.

Signed-off-by: Xi Luo <xluo12@vols.utk.edu>
Signed-off-by: Joseph Schuchart <schuchart@icl.utk.edu>
Signed-off-by: George Bosilca <bosilca@icl.utk.edu>

Author: bosilca

ompi/communicator/comm.c

@@ -401,11 +401,10 @@ int ompi_comm_create ( ompi_communicator_t *comm, ompi_group_t *group,
 /**********************************************************************/
 /**********************************************************************/
 /**********************************************************************/
-/*
-** Counterpart to MPI_Comm_split. To be used within OMPI (e.g. MPI_Cart_sub).
-*/
-int ompi_comm_split( ompi_communicator_t* comm, int color, int key,
-                     ompi_communicator_t **newcomm, bool pass_on_topo )
+
+int ompi_comm_split_with_info( ompi_communicator_t* comm, int color, int key,
+                               opal_info_t *info,
+                               ompi_communicator_t **newcomm, bool pass_on_topo )
 {
     int myinfo[2];
     int size, my_size;
@@ -611,7 +610,11 @@ int ompi_comm_split( ompi_communicator_t* comm, int color, int key,
     snprintf(newcomp->c_name, MPI_MAX_OBJECT_NAME, "MPI COMMUNICATOR %d SPLIT FROM %d",
              newcomp->c_contextid, comm->c_contextid );
 
-
+    /* Copy info if there is one */
+    if (info) {
+        newcomp->super.s_info = OBJ_NEW(opal_info_t);
+        opal_info_dup(info, &(newcomp->super.s_info));
+    }
 
     /* Activate the communicator and init coll-component */
     rc = ompi_comm_activate (&newcomp, comm, NULL, NULL, NULL, false, mode);
@@ -638,6 +641,15 @@ int ompi_comm_split( ompi_communicator_t* comm, int color, int key,
 }
 
 
+/*
+** Counterpart to MPI_Comm_split. To be used within OMPI (e.g. MPI_Cart_sub).
+*/
+int ompi_comm_split( ompi_communicator_t* comm, int color, int key,
+                     ompi_communicator_t **newcomm, bool pass_on_topo )
+{
+    return ompi_comm_split_with_info(comm, color, key, NULL, newcomm, pass_on_topo);
+}
+
 /**********************************************************************/
 /**********************************************************************/
 /**********************************************************************/

ompi/communicator/communicator.h

@@ -463,6 +463,21 @@ int ompi_topo_dist_graph_create_adjacent(ompi_communicator_t *old_comm,
 OMPI_DECLSPEC int ompi_comm_split (ompi_communicator_t *comm, int color, int key,
                                    ompi_communicator_t** newcomm, bool pass_on_topo);
 
+/**
+ * split a communicator based on color and key. Parameters
+ * are identical to the MPI-counterpart of the function.
+ * Similar to \see ompi_comm_split with an additional info parameter.
+ *
+ * @param comm: input communicator
+ * @param color
+ * @param key
+ *
+ * @
+ */
+OMPI_DECLSPEC int ompi_comm_split_with_info( ompi_communicator_t* comm, int color, int key,
+                                             opal_info_t *info,
+                                             ompi_communicator_t **newcomm, bool pass_on_topo );
+
 /**
  * split a communicator based on type and key. Parameters
  * are identical to the MPI-counterpart of the function.

ompi/group/group.c

@@ -578,3 +578,31 @@ bool ompi_group_have_remote_peers (ompi_group_t *group)
 
     return false;
 }
+
+/**
+ * Count the number of processes on this group that share the same node as
+ * this process.
+ */
+int ompi_group_count_local_peers (ompi_group_t *group)
+{
+    int local_peers = 0;
+    for (int i = 0 ; i < group->grp_proc_count ; ++i) {
+        ompi_proc_t *proc = NULL;
+#if OMPI_GROUP_SPARSE
+        proc = ompi_group_peer_lookup (group, i);
+#else
+        proc = ompi_group_get_proc_ptr_raw (group, i);
+        if (ompi_proc_is_sentinel (proc)) {
+            /* the proc must be stored in the group or cached in the proc
+             * hash table if the process resides in the local node
+             * (see ompi_proc_complete_init) */
+            continue;
+        }
+#endif
+        if (OPAL_PROC_ON_LOCAL_NODE(proc->super.proc_flags)) {
+            local_peers++;
+        }
+    }
+
+    return local_peers;
+}

ompi/group/group.h

@@ -420,8 +420,16 @@ static inline struct ompi_proc_t *ompi_group_peer_lookup_existing (ompi_group_t
     return ompi_group_get_proc_ptr (group, peer_id, false);
 }
 
+/**
+ * Return true if all processes in the group are not on the local node.
+ */
 bool ompi_group_have_remote_peers (ompi_group_t *group);
 
+/**
+ * Count the number of processes on the local node.
+ */
+int ompi_group_count_local_peers (ompi_group_t *group);
+
 /**
  *  Function to print the group info
  */

ompi/mca/coll/adapt/coll_adapt_ibcast.c

@@ -178,7 +178,7 @@ static int send_cb(ompi_request_t * req)
         || (context->con->tree->tree_nextsize > 0 && rank != context->con->root
             && num_sent == context->con->tree->tree_nextsize * context->con->num_segs
             && num_recv_fini == context->con->num_segs)) {
-        OPAL_OUTPUT_VERBOSE((30, mca_coll_adapt_component.adapt_output, "[%d]: Singal in send\n",
+        OPAL_OUTPUT_VERBOSE((30, mca_coll_adapt_component.adapt_output, "[%d]: Signal in send\n",
                              ompi_comm_rank(context->con->comm)));
         ibcast_request_fini(context);
     }
@@ -306,7 +306,7 @@ static int recv_cb(ompi_request_t * req)
             && num_recv_fini == context->con->num_segs)
         || (context->con->tree->tree_nextsize == 0
             && num_recv_fini == context->con->num_segs)) {
-        OPAL_OUTPUT_VERBOSE((30, mca_coll_adapt_component.adapt_output, "[%d]: Singal in recv\n",
+        OPAL_OUTPUT_VERBOSE((30, mca_coll_adapt_component.adapt_output, "[%d]: Signal in recv\n",
                              ompi_comm_rank(context->con->comm)));
         ibcast_request_fini(context);
     }

ompi/mca/coll/base/coll_base_comm_select.c

@@ -38,6 +38,7 @@
 #include "mpi.h"
 #include "ompi/communicator/communicator.h"
 #include "opal/util/output.h"
+#include "opal/util/argv.h"
 #include "opal/util/show_help.h"
 #include "opal/class/opal_list.h"
 #include "opal/class/opal_object.h"
@@ -312,6 +313,20 @@ static int avail_coll_compare (opal_list_item_t **a,
     return 0;
 }
 
+static inline int
+component_in_argv(char **argv, const char* component_name)
+{
+    if( NULL != argv ) {
+        while( NULL != *argv ) {
+            if( 0 == strcmp(component_name, *argv) ) {
+                return 1;
+            }
+            argv++;  /* move to the next argument */
+        }
+    }
+    return 0;
+}
+
 /*
  * For each module in the list, check and see if it wants to run, and
  * do the resulting priority comparison.  Make a list of modules to be
@@ -321,20 +336,80 @@ static int avail_coll_compare (opal_list_item_t **a,
 static opal_list_t *check_components(opal_list_t * components,
                                      ompi_communicator_t * comm)
 {
-    int priority;
+    int priority, flag;
     const mca_base_component_t *component;
     mca_base_component_list_item_t *cli;
     mca_coll_base_module_2_3_0_t *module;
     opal_list_t *selectable;
     mca_coll_base_avail_coll_t *avail;
-
+    char info_val[OPAL_MAX_INFO_VAL+1];
+    char **coll_argv = NULL, **coll_exclude = NULL, **coll_include = NULL;
+
+    /* Check if this communicator comes with restrictions on the collective modules
+     * it wants to use. The restrictions are consistent with the MCA parameter
+     * to limit the collective components loaded, but it applies for each
+     * communicator and is provided as an info key during the communicator
+     * creation. Unlike the MCA param, this info key is used not to select
+     * components but either to prevent components from being used or to
+     * force a change in the component priority.
+     */
+    if( NULL != comm->super.s_info) {
+        opal_info_get(comm->super.s_info, "ompi_comm_coll_preference",
+                      sizeof(info_val), info_val, &flag);
+        if( !flag ) {
+            goto proceed_to_select;
+        }
+        coll_argv = opal_argv_split(info_val, ',');
+        if(NULL == coll_argv) {
+            goto proceed_to_select;
+        }
+        int idx2, count_include = opal_argv_count(coll_argv);
+        /* Allocate the coll_include argv */
+        coll_include = (char**)malloc((count_include + 1) * sizeof(char*));
+        coll_include[count_include] = NULL; /* NULL terminated array */
+        /* Dispatch the include/exclude in the corresponding arrays */
+        for( int idx = 0; NULL != coll_argv[idx]; idx++ ) {
+            if( '^' == coll_argv[idx][0] ) {
+                coll_include[idx] = NULL;  /* NULL terminated array */
+
+                /* Allocate the coll_exclude argv */
+                coll_exclude = (char**)malloc((count_include - idx + 1) * sizeof(char*));
+                /* save the exclude components */
+                for( idx2 = idx; NULL != coll_argv[idx2]; idx2++ ) {
+                    coll_exclude[idx2 - idx] = coll_argv[idx2];
+                }
+                coll_exclude[idx2 - idx] = NULL;  /* NULL-terminated array */
+                coll_exclude[0] = coll_exclude[0] + 1;  /* get rid of the ^ */
+                count_include = idx;
+                break;
+            }
+            coll_include[idx] = coll_argv[idx];
+        }
+        /* Reverse the order of the coll_inclide argv to faciliate the ordering of
+         * the selected components reverse.
+         */
+        for( idx2 = 0; idx2 < (count_include - 1); idx2++ ) {
+            char* temp = coll_include[idx2];
+            coll_include[idx2] = coll_include[count_include - 1];
+            coll_include[count_include - 1] = temp;
+            count_include--;
+        }
+    }
+ proceed_to_select:
     /* Make a list of the components that query successfully */
     selectable = OBJ_NEW(opal_list_t);
 
     /* Scan through the list of components */
     OPAL_LIST_FOREACH(cli, &ompi_coll_base_framework.framework_components, mca_base_component_list_item_t) {
         component = cli->cli_component;
 
+        /* dont bother is we have this component in the exclusion list */
+        if( component_in_argv(coll_exclude, component->mca_component_name) ) {
+            opal_output_verbose(10, ompi_coll_base_framework.framework_output,
+                                "coll:base:comm_select: component disqualified: %s (due to communicator info key)",
+                                component->mca_component_name );
+            continue;
+        }
         priority = check_one_component(comm, component, &module);
         if (priority >= 0) {
             /* We have a component that indicated that it wants to run
@@ -370,6 +445,27 @@ static opal_list_t *check_components(opal_list_t * components,
     /* Put this list in priority order */
     opal_list_sort(selectable, avail_coll_compare);
 
+    /* For all valid component reorder them not on their provided priorities but on
+     * the order requested in the info key. As at this point the coll_include is
+     * already ordered backward we can simply prepend the components.
+     */
+    mca_coll_base_avail_coll_t *item, *item_next;
+    OPAL_LIST_FOREACH_SAFE(item, item_next,
+                           selectable, mca_coll_base_avail_coll_t) {
+        if( component_in_argv(coll_include, item->ac_component_name) ) {
+            opal_list_remove_item(selectable, &item->super);
+            opal_list_prepend(selectable, &item->super);
+        }
+    }
+
+    opal_argv_free(coll_argv);
+    if( NULL != coll_exclude ) {
+        free(coll_exclude);
+    }
+    if( NULL != coll_include ) {
+        free(coll_include);
+    }
+
     /* All done */
     return selectable;
 }
@@ -403,7 +499,6 @@ static int check_one_component(ompi_communicator_t * comm,
     return priority;
 }
 
-
 /**************************************************************************
  * Query functions
  **************************************************************************/