Adding the required logic to select a topo module at runtime. This is done primarily by topo_base_select

This commit was SVN r831.

src/mca/mpi/topo/base/base.h

@@ -74,5 +74,7 @@ extern "C" {
  */
 extern int mca_topo_base_output;
 extern lam_list_t mca_topo_base_modules_available;
+extern mca_topo_base_module_t mca_topo_base_selected_module;
+extern mca_topo_t mca_topo;
 
 #endif /* MCA_BASE_TOPO_H */

src/mca/mpi/topo/base/topo_base_open.c

@@ -21,6 +21,8 @@
  */
 int mca_topo_base_output = -1;
 lam_list_t mca_topo_base_modules_available;
+mca_topo_base_module_t mca_topo_base_selected_module;
+mca_topo_t mca_topo;
 
 /**
  * Functions for finding and opening either all the MCA topo modules, or
@@ -35,6 +37,9 @@ int mca_topo_base_open(void) {
                                  &mca_topo_base_modules_available)) {
         return LAM_ERROR;
     }
+    /*
+     * All done
+     */ 
 
     return LAM_SUCCESS;
 }

src/mca/mpi/topo/base/topo_base_select.c

@@ -3,20 +3,179 @@
  */
 
 #include "lam_config.h"
+
 #include "mca/mca.h"
+#include "lam/lfc/lam_list.h"
+#include "lam/runtime/runtime.h"
+#include "mca/mca.h"
+#include "mca/lam/base/base.h"
 #include "mca/mpi/topo/topo.h"
 #include "mca/mpi/topo/base/base.h"
 
-int mca_topo_base_select (lam_list_t *selected, 
+
+/*
+ * This structure is needed so that we can close the modules 
+ * which are not selected but were opened. mca_base_modules_close
+ * which does this job for us requires a lam_list_t which contains
+ * these modules
+ */
+struct opened_module_t {
+    lam_list_item_t super;
+    mca_topo_base_module_t *om_module;
+};
+typedef struct opened_module_t opened_module_t;
+
+/*
+ * Only one topo module can be attached to each communicator.
+ *
+ * This function calls the init function on all the modules which
+ * were opened by mca_base_modules_open. init function for each 
+ * module returns the priority for each module and hence this
+ * function is able to select on particular module from a plethora
+ * of modules available to implement topology. The selected module 
+ * will have all its function pointers saved and returned to the
+ * caller
+ */  
+
+int mca_topo_base_select (mca_topo_t *selected, 
                           bool *allow_multi_user_thread,
                           bool *have_hidden_threads) {
 
-    /*
-     * Nothing to be done as of now
-     */
-    *allow_multi_user_threads = true;
-    *have_hidden_threads = false;
+    int priority; 
+    int best_priority; 
+    bool user_threads;
+    bool hidden_threads;
+    lam_list_item_t *item; 
+    mca_base_module_list_item_t *mli;
+    mca_topo_base_module_t *module; 
+    mca_topo_base_module_t *best_module;
+    mca_topo_t *actions; 
+    opened_module_t *om;
 
+    /*
+     * Traverse the list of opened modules.
+     */
+    best_module = NULL;
+    best_priority = -1;
+    for (item = lam_list_get_first(&mca_topo_base_modules_available);
+         item != lam_list_get_end(&mca_topo_base_modules_available);
+         item = lam_list_get_next(item)) {
+       /*
+        * convert the lam_list_item_t returned into the proper type
+        */
+       mli = (mca_base_module_list_item_t *) item;
+       module = (mca_topo_base_module_t *) mli->mli_module;
+
+       lam_output_verbose(10, mca_topo_base_output,
+                          "select: initialising %s module %s",
+                          module->topom_version.mca_type_name,
+                          module->topom_version.mca_module_name);
+
+       if (NULL == module->topom_int) {
+          /*
+           * there is no initialisation function in this module
+           */
+          lam_output_verbose(10, mca_topo_base_output,
+                             "select: no init, ignoring the module");
+       } else {
+           actions = module->topom_init (&priority,
+                                         &user_threads,
+                                         &hidden_threads);
+           if (NULL == actions) {
+               lam_output_verbose(10, mca_topo_base_module,
+                                  "select: init returned failure");
+           } else {
+               lam_output_verbose(10, mca_topo_base_module,
+                                  "select: init returned priority &d",
+                                  priority);
+               if (priority > best_priority) {
+                   /* 
+                    * this module is the best we have found till now
+                    */
+                   best_priority = priority;
+                   best_user_threads = user_threads;
+                   best_hidden_threads = hidden_threads;
+                   best_module = module;
+               }
+
+               om = (opened_module_t *) malloc(sizeof(opened_module_t)); 
+               if (NULL == om) {
+                   /*
+                    * out of space I guess
+                    */
+                   return LAM_ERR_OUT_OF_RESOURCE;
+               }
+               OBJ_CONSTRUCT(om, lam_list_item_t);
+               om->om_module = module;
+               lam_list_append(&opened, (lam_list_item_t *)om); 
+           } /* end else of if (NULL == actions) */
+       } /* end else of if (NULL == module->topom_init) */
+    } /* end for ... end of traversal */
+
+    /*
+     * Now we have alist of modules which successfully initialised.
+     * This list is contained in opened. Also, we have the highest
+     * priority returned which is of the module "best_module". We now
+     * have to close all those modules which "lost" the race to 
+     * get chosen
+     */
+    if (NULL == best_module) {
+       /*
+        * This typically means that there was no module which was able
+        * to run properly this time. So, we need to abort
+        *
+        * JMS replace with show_help
+        */
+       lam_abort(1, "No topo module avaliable. This should not happen");
+    }
+
+    for (item = lam_list_remove_first(&opened);
+         NULL != item;
+         item = lam_list_remove_first(&opened)) {
+            om = (opened_module_t *) item;
+            if (om->om_module != best_module) {
+              /*
+               * this is not the "choosen one", discard this   
+               */
+               if (NULL != om->om_module->topom_finalize) {
+                  /* finalise the module only if they have some
+                   * clean up job to do. Modules which are opened
+                   * but do not actually do anything typically do not 
+                   * have a finalize. Hence this check is necessary
+                   */
+                   om->om_module->topom_finalize();
+                   lam_output_verbose(10, mca_topo_base_output,
+                                      "select: module %s is not selected",
+                                      om->om_module->topom_version.mca_module_name);
+               } /* end if */
+            } /* if not best module */
+            free(om);
+    } /* traversing through the entire list */
+
+    /*
+     * Now we have to unload all the modules which were not selected 
+     * through mca_base_modules_close. After this function call, the
+     * mca_topo_base_available_modules will contain only the selected
+     * module
+     */
+    mca_base_modules_close(mca_topo_base_output,
+                           &mca_topo_base_modules_available,
+                           (mca_base_module_t *) best_module);
+
+    /*
+     * save the selected module
+     */
+   mca_topo_base_selected_module = *best_module;
+   mca_topo = *actions;
+   *selected = *actions;
+   *allow_multi_user_threads = best_user_threads;
+   *have_hidden_threads = best_hidden_threads;
+   lam_output_verbose(10, mca_topo_base_output,
+                      "select: module %s selected",
+                      module->topom_version.mca_module_name);
+
+   /*
+    * I think we are done :-)
+    */
     return LAM_SUCCESS;
 }
-