change reduce-scatter/gather for non-power of 2. Spreading out the

load for the non-power of 2 phase of the reduction.

This commit was SVN r18486.

ompi/mca/coll/sm2/coll_sm2_reduce.c

@@ -410,6 +410,7 @@ int mca_coll_sm2_reduce_intra_reducescatter_gather(void *sbuf, void *rbuf,
     long long tag, base_tag;
     sm_work_buffer_t *sm_buffer_desc;
     volatile char * extra_rank_write_data_pointer;
+    volatile char * my_extra_write_pointer;
     volatile char * partner_base_pointer;
     volatile char * my_pointer;
     volatile char * my_base_pointer;
@@ -518,22 +519,65 @@ int mca_coll_sm2_reduce_intra_reducescatter_gather(void *sbuf, void *rbuf,
             
         /* copy data in from the "extra" source, if need be */
         tag=base_tag;
-        if(0 < my_exchange_node->n_extra_sources)  {
-            if ( EXCHANGE_NODE == my_exchange_node->node_type ) {
-                extra_rank=my_exchange_node->rank_extra_source;
-                extra_ctl_pointer=
-                    sm_buffer_desc->proc_memory[extra_rank].control_region;
-                extra_rank_write_data_pointer=
-                    sm_buffer_desc->proc_memory[extra_rank].data_segment;
+            if(0 < my_exchange_node->n_extra_sources)  {
+                int n_my_count;
+
+                if ( EXCHANGE_NODE == my_exchange_node->node_type ) {
+
+                    /* signal to partner that I am ready */
+                    MB();
+                    /*
+                     * Signal extra node that data is ready
+                     */
+                    my_ctl_pointer->flag=tag;
+
+                    /* figure out my portion of the reduction */
+                    n_my_count=count_this_stripe/2;
+
+                    extra_rank=my_exchange_node->rank_extra_source;
+                    extra_ctl_pointer=
+                        sm_buffer_desc->proc_memory[extra_rank].control_region;
+                    extra_rank_write_data_pointer=
+                        sm_buffer_desc->proc_memory[extra_rank].data_segment;
+                    
+                    /* wait until remote data is read */
+                    while( extra_ctl_pointer->flag < tag ) {
+                        opal_progress();
+                    }
+
+                    /* apply collective operation to first half of the data */
+                    if( 0 < n_my_count ) {
+                        ompi_op_reduce(op,(void *)extra_rank_write_data_pointer,
+                                (void *)my_base_pointer, n_my_count,dtype);
+                    }
+
+
+                    /* wait for my partner to finish reducing the data */
+                    tag=base_tag+1;
+                    while( extra_ctl_pointer->flag < tag ) {
+                        opal_progress();
+                    }
+
+
+                    /* read my partner's data */
    
-                /* wait until remote data is read */
-                while( extra_ctl_pointer->flag < tag ) {
-                    opal_progress();
-                }
-    
-                /* apply collective operation */
-                ompi_op_reduce(op,(void *)extra_rank_write_data_pointer,
-                        (void *)my_base_pointer, count_this_stripe,dtype);
+                    /* adjust read an write pointers */
+                    extra_rank_write_data_pointer+=(n_my_count*dt_extent);
+
+                    if( 0 < (count_this_stripe-n_my_count) ) {
+                        rc=ompi_ddt_copy_content_same_ddt(dtype, 
+                                count_this_stripe-n_my_count,
+                                (char *)(my_base_pointer+n_my_count*dt_extent),
+                                (char *)extra_rank_write_data_pointer);
+                        if( 0 != rc ) {
+                            return OMPI_ERROR;
+                        }
+                    }
+                
+                    /* now we are ready for the power of 2 portion of the
+                     *   algorithm
+                     */
+
             } else {
         
                 /* set memory barriet to make sure data is in main memory before
@@ -543,10 +587,41 @@ int mca_coll_sm2_reduce_intra_reducescatter_gather(void *sbuf, void *rbuf,
                 MB();
     
                 /*
-                 * Signal parent that data is ready
+                 * Signal extra node that data is ready
                  */
                 my_ctl_pointer->flag=tag;
 
+                /* figure out my portion of the reduction */
+                n_my_count=count_this_stripe-(count_this_stripe/2);
+
+                /* get the pointer to the partners data that needs to be reduced */
+                extra_rank=my_exchange_node->rank_extra_source;
+                extra_ctl_pointer=
+                    sm_buffer_desc->proc_memory[extra_rank].control_region;
+                extra_rank_write_data_pointer=
+                    sm_buffer_desc->proc_memory[extra_rank].data_segment;
+                /* offset into my half of the data */
+                extra_rank_write_data_pointer+= 
+                        ((count_this_stripe/2)*dt_extent);
+                my_extra_write_pointer=my_base_pointer+
+                    ((count_this_stripe/2)*dt_extent);
+                    
+                /* wait until remote data is read */
+                while( extra_ctl_pointer->flag < tag ) {
+                    opal_progress();
+                }
+
+                /* apply collective operation to second half of the data  */
+                if( 0 < n_my_count ) {
+                    ompi_op_reduce(op,(void *)extra_rank_write_data_pointer,
+                            (void *)my_extra_write_pointer, n_my_count,dtype);
+                }
+
+                /* signal that I am done, so my partner can read my data */
+                MB();
+                tag=base_tag+1;
+                my_ctl_pointer->flag=tag;
+
             }
         }
         MB();