Merge pull request #6814 from brminich/tuned_all2all_select

COLL/TUNED: Update alltoall selection rule for mellanox platform

contrib/platform/mellanox/optimized.conf

@@ -78,3 +78,8 @@ opal_event_include=epoll
 
 bml_r2_show_unreach_errors = 0
 
+# alltoall algorithm selection settings for tuned coll mca
+coll_tuned_alltoall_large_msg              = 250000
+coll_tuned_alltoall_min_procs              = 2048
+coll_tuned_alltoall_algorithm_max_requests = 8
+

ompi/mca/coll/tuned/coll_tuned.h

@@ -38,6 +38,9 @@ extern int   ompi_coll_tuned_init_chain_fanout;
 extern int   ompi_coll_tuned_init_max_requests;
 extern int   ompi_coll_tuned_alltoall_small_msg;
 extern int   ompi_coll_tuned_alltoall_intermediate_msg;
+extern int   ompi_coll_tuned_alltoall_large_msg;
+extern int   ompi_coll_tuned_alltoall_min_procs;
+extern int   ompi_coll_tuned_alltoall_max_requests;
 
 /* forced algorithm choices */
 /* this structure is for storing the indexes to the forced algorithm mca params... */

ompi/mca/coll/tuned/coll_tuned_alltoall_decision.c

@@ -28,7 +28,6 @@
 /* alltoall algorithm variables */
 static int coll_tuned_alltoall_forced_algorithm = 0;
 static int coll_tuned_alltoall_segment_size = 0;
-static int coll_tuned_alltoall_max_requests;
 static int coll_tuned_alltoall_tree_fanout;
 static int coll_tuned_alltoall_chain_fanout;
 
@@ -115,7 +114,22 @@ int ompi_coll_tuned_alltoall_intra_check_forced_init (coll_tuned_force_algorithm
                                       MCA_BASE_VAR_SCOPE_ALL,
                                       &coll_tuned_alltoall_chain_fanout);
 
-    coll_tuned_alltoall_max_requests = 0; /* no limit for alltoall by default */
+    (void) mca_base_component_var_register(&mca_coll_tuned_component.super.collm_version,
+                                           "alltoall_large_msg",
+                                           "use pairwise exchange algorithm for messages larger than this value",
+                                           MCA_BASE_VAR_TYPE_INT, NULL, 0, 0,
+                                           OPAL_INFO_LVL_6,
+                                           MCA_BASE_VAR_SCOPE_READONLY,
+                                           &ompi_coll_tuned_alltoall_large_msg);
+
+    (void) mca_base_component_var_register(&mca_coll_tuned_component.super.collm_version,
+                                           "alltoall_min_procs",
+                                           "use pairwise exchange algorithm for communicators larger than this value",
+                                           MCA_BASE_VAR_TYPE_INT, NULL, 0, 0,
+                                           OPAL_INFO_LVL_6,
+                                           MCA_BASE_VAR_SCOPE_READONLY,
+                                           &ompi_coll_tuned_alltoall_min_procs);
+
     mca_param_indices->max_requests_param_index =
       mca_base_component_var_register(&mca_coll_tuned_component.super.collm_version,
                                       "alltoall_algorithm_max_requests",
@@ -123,17 +137,16 @@ int ompi_coll_tuned_alltoall_intra_check_forced_init (coll_tuned_force_algorithm
                                       MCA_BASE_VAR_TYPE_INT, NULL, 0, MCA_BASE_VAR_FLAG_SETTABLE,
                                       OPAL_INFO_LVL_5,
                                       MCA_BASE_VAR_SCOPE_ALL,
-                                      &coll_tuned_alltoall_max_requests);
+                                      &ompi_coll_tuned_alltoall_max_requests);
     if (mca_param_indices->max_requests_param_index < 0) {
         return mca_param_indices->max_requests_param_index;
     }
 
-    if (coll_tuned_alltoall_max_requests < 0) {
+    if (ompi_coll_tuned_alltoall_max_requests < 0) {
         if( 0 == ompi_comm_rank( MPI_COMM_WORLD ) ) {
-            opal_output( 0, "Maximum outstanding requests must be positive number greater than 1.  Switching to system level default %d \n",
+            opal_output( 0, "Maximum outstanding requests must be positive number greater than 1.  Switching to 0 \n");
-                         ompi_coll_tuned_init_max_requests );
         }
-        coll_tuned_alltoall_max_requests = 0;
+        ompi_coll_tuned_alltoall_max_requests = 0;
     }
 
     return (MPI_SUCCESS);

ompi/mca/coll/tuned/coll_tuned_component.c

@@ -57,6 +57,13 @@ int   ompi_coll_tuned_init_max_requests = 128;
 int   ompi_coll_tuned_alltoall_small_msg = 200;
 int   ompi_coll_tuned_alltoall_intermediate_msg = 3000;
 
+/* Set it to the same value as intermediate msg by default, so it does not affect
+ * default algorithm selection. Changing this value will force using linear with
+ * sync algorithm on certain message sizes. */
+int   ompi_coll_tuned_alltoall_large_msg = 3000;
+int   ompi_coll_tuned_alltoall_min_procs = 0; /* disable by default */
+int   ompi_coll_tuned_alltoall_max_requests  = 0; /* no limit for alltoall by default */
+
 /* forced alogrithm variables */
 /* indices for the MCA parameters */
 coll_tuned_force_algorithm_mca_param_indices_t ompi_coll_tuned_forced_params[COLLCOUNT] = {{0}};

ompi/mca/coll/tuned/coll_tuned_decision_fixed.c

@@ -136,6 +136,12 @@ int ompi_coll_tuned_alltoall_intra_dec_fixed(const void *sbuf, int scount,
         return ompi_coll_base_alltoall_intra_basic_linear(sbuf, scount, sdtype,
                                                           rbuf, rcount, rdtype,
                                                           comm, module);
+    } else if ((block_dsize < (size_t) ompi_coll_tuned_alltoall_large_msg) &&
+               (communicator_size <= ompi_coll_tuned_alltoall_min_procs)) {
+        return ompi_coll_base_alltoall_intra_linear_sync(sbuf, scount, sdtype,
+                                                         rbuf, rcount, rdtype,
+                                                         comm, module,
+                                                         ompi_coll_tuned_alltoall_max_requests);
     }
 
     return ompi_coll_base_alltoall_intra_pairwise(sbuf, scount, sdtype,