When doing comm-spawn, track the last object we bound to and ensure that we start the next job on the next object so we avoid overload situations when they aren't necessary

orte/mca/plm/base/plm_base_receive.c

@@ -224,6 +224,8 @@ void orte_plm_base_recv(int status, orte_process_name_t* sender,
                 jdata->bookmark = parent->bookmark;
             }
         }
+        /* provide the parent's last object */
+        jdata->bkmark_obj = parent->bkmark_obj;
 
         /* launch it */
         OPAL_OUTPUT_VERBOSE((5, orte_plm_base_framework.framework_output,

orte/mca/rmaps/round_robin/rmaps_rr_mappers.c

@@ -500,6 +500,11 @@ int orte_rmaps_rr_byobj(orte_job_t *jdata,
                                 "mca:rmaps:rr: found %u %s objects on node %s",
                                 nobjs, hwloc_obj_type_string(target), node->name);
 
+            /* if this is a comm_spawn situation, start with the object
+             * where the parent left off and increment */
+            if (ORTE_JOBID_INVALID != jdata->originator.jobid) {
+                start = (jdata->bkmark_obj + 1) % nobjs;
+            }
             /* compute the number of procs to go on this node */
             nprocs = (node->slots - node->slots_inuse) / orte_rmaps_base.cpus_per_rank;
             opal_output_verbose(2, orte_rmaps_base_framework.framework_output,

orte/runtime/orte_globals.c

@@ -651,6 +651,7 @@ static void orte_job_construct(orte_job_t* job)
                             ORTE_GLOBAL_ARRAY_BLOCK_SIZE);
     job->map = NULL;
     job->bookmark = NULL;
+    job->bkmark_obj = 0;
     job->state = ORTE_JOB_STATE_UNDEF;
 
     job->num_mapped = 0;

orte/runtime/orte_globals.h

@@ -333,6 +333,9 @@ typedef struct {
      * indicates the node where we stopped
      */
     orte_node_t *bookmark;
+    /* if we are binding, bookmark the index of the
+     * last object we bound to */
+    unsigned int bkmark_obj;
     /* state of the overall job */
     orte_job_state_t state;
     /* number of procs mapped */