Added MXM parameter "np" that controls the minimal number of processes that allow MXM to run

Default: 128

MXM advantages kick in with large number of processes.

This commit was SVN r26544.

ompi/mca/mtl/mxm/mtl_mxm.c

@@ -110,7 +110,6 @@ int ompi_mtl_mxm_module_init(void)
     mxm_error_t err;
     uint32_t jobid;
     uint64_t mxlr;
-    int rc;
     ompi_proc_t *mp, **procs;
     unsigned    ptl_bitmap;
     size_t totps, proc;
@@ -139,6 +138,13 @@ int ompi_mtl_mxm_module_init(void)
         return OMPI_ERROR;
     }
 
+    if (totps < (size_t)ompi_mtl_mxm.mxm_np) {
+        MXM_VERBOSE(1, "MXM support will be disabled because of total number of processes"
+                "(%lu) is less then default (%u)",totps, ompi_mtl_mxm.mxm_np);
+                return OMPI_ERR_NOT_SUPPORTED;
+    }
+    MXM_VERBOSE(1, "MXM support enabled");
+
     for (proc = 0; proc < totps; proc++) {
         if (mp == procs[proc]) {
             lr = nlps++;

ompi/mca/mtl/mxm/mtl_mxm_component.c

@@ -60,13 +60,22 @@ mca_mtl_mxm_component_t mca_mtl_mxm_component = {
 
 static int ompi_mtl_mxm_component_register(void)
 {
+    mca_base_component_t*c;
 
-    mca_base_param_reg_int(&mca_mtl_mxm_component.super.mtl_version, "verbose",
+    c = &mca_mtl_mxm_component.super.mtl_version;
+
+    mca_base_param_reg_int(c, "verbose",
                            "Verbose level of the MXM component",
                            false, false,
                            0,
                            &ompi_mtl_mxm.verbose);
 
+    mca_base_param_reg_int(c, "np",
+            "[integer] Minimal allowed job's NP to activate MXM",
+            false, false,
+            128,
+            &ompi_mtl_mxm.mxm_np);
+
     return OMPI_SUCCESS;
 }
 

ompi/mca/mtl/mxm/mtl_mxm_types.h

@@ -27,6 +27,7 @@ BEGIN_C_DECLS
 typedef struct mca_mtl_mxm_module_t {
     mca_mtl_base_module_t super; /**< base MTL interface */
     int                   verbose;
+    int                   mxm_np;
     mxm_h                 mxm_context;
     mxm_context_opts_t    mxm_opts;
     mxm_ep_h              ep;