Make sure the PML is consistent across the world.

Temporary solution for the PML inconsistency issue discussed in #7475.
This patch address 2 things: first it make the PMIx key optional so that
if we are not in a full modex mode we don't do a direct modex, and
second it get the PML info from the vpid 0 instead of from the local
rank.

Signed-off-by: George Bosilca <bosilca@icl.utk.edu>

Author: bosilca

ompi/mca/pml/base/pml_base_select.c

@@ -324,6 +324,7 @@ mca_pml_base_pml_check_selected(const char *my_pml,
     size_t size;
     int ret;
     char *remote_pml;
+    opal_process_name_t rank0 = {.jobid = ompi_proc_local()->super.proc_name.jobid, .vpid = 0};
 
     /* if no modex was required by the PML, then
      * we can assume success
@@ -342,13 +343,13 @@ mca_pml_base_pml_check_selected(const char *my_pml,
     }
 
     /* get the name of the PML module selected by rank=0 */
-    OPAL_MODEX_RECV(ret, &pml_base_component,
-                    &procs[0]->super.proc_name, (void**) &remote_pml, &size);
+    OPAL_MODEX_RECV_STRING_OPTIONAL(ret, mca_base_component_to_string(&pml_base_component),
+                                    &rank0, (void**) &remote_pml, &size);
 
     /* if this key wasn't found, then just assume all is well... */
-    if (OMPI_SUCCESS != ret) {
+    if (PMIX_ERR_NOT_FOUND != ret) {
         opal_output_verbose( 10, ompi_pml_base_framework.framework_output,
-                            "check:select: modex data not found");
+                            "check:select: PML modex for vpid 0 data not found");
         return OMPI_SUCCESS;
     }
 

opal/mca/pmix/pmix-internal.h

@@ -301,14 +301,14 @@ typedef struct {
  *     is to be returned
  * t - the expected data type
  */
-#define OPAL_MODEX_RECV_VALUE_IMMEDIATE(r, s, p, d, t)                                   \
-    do {                                                                                 \
+#define OPAL_MODEX_RECV_VALUE_IMMEDIATE(r, s, p, d, t)                                  \
+    do {                                                                                \
         pmix_proc_t _proc;                                                              \
         pmix_value_t *_kv = NULL;                                                       \
         pmix_info_t _info;                                                              \
         size_t _sz;                                                                     \
         OPAL_OUTPUT_VERBOSE((1, opal_pmix_verbose_output,                               \
-                            "%s[%s:%d] MODEX RECV VALUE OPTIONAL FOR PROC %s KEY %s",   \
+                            "%s[%s:%d] MODEX RECV VALUE IMMEDIATE FOR PROC %s KEY %s",  \
                             OPAL_NAME_PRINT(OPAL_PROC_MY_NAME),                         \
                             __FILE__, __LINE__,                                         \
                             OPAL_NAME_PRINT(*(p)), (s)));                               \
@@ -349,7 +349,7 @@ typedef struct {
                             OPAL_NAME_PRINT(OPAL_PROC_MY_NAME),                 \
                             __FILE__, __LINE__,                                 \
                             OPAL_NAME_PRINT(*(p)), (s)));                       \
-        OPAL_PMIX_CONVERT_NAME(&_proc, (p));                                   \
+        OPAL_PMIX_CONVERT_NAME(&_proc, (p));                                    \
         (r) = PMIx_Get(&(_proc), (s), NULL, 0, &(_kv));                         \
         if (NULL == _kv) {                                                      \
             (r) = PMIX_ERR_NOT_FOUND;                                           \
@@ -363,6 +363,46 @@ typedef struct {
         }                                                                       \
     } while(0);
 
+/**
+ * Provide a simplified macro for retrieving modex data
+ * from another process:
+ *
+ * r - the integer return status from the modex op (int)
+ * s - string key (char*)
+ * p - pointer to the opal_process_name_t of the proc that posted
+ *     the data (opal_process_name_t*)
+ * d - pointer to a location wherein the data object
+ *     it to be returned (char**)
+ * sz - pointer to a location wherein the number of bytes
+ *     in the data object can be returned (size_t)
+ */
+#define OPAL_MODEX_RECV_STRING_OPTIONAL(r, s, p, d, sz)                                \
+    do {                                                                               \
+        pmix_proc_t _proc;                                                             \
+        pmix_value_t *_kv = NULL;                                                      \
+        pmix_info_t _info;                                                             \
+        OPAL_OUTPUT_VERBOSE((1, opal_pmix_verbose_output,                              \
+                            "%s[%s:%d] MODEX RECV STRING OPTIONAL FOR PROC %s KEY %s", \
+                            OPAL_NAME_PRINT(OPAL_PROC_MY_NAME),                        \
+                            __FILE__, __LINE__,                                        \
+                            OPAL_NAME_PRINT(*(p)), (s)));                              \
+        *(d) = NULL;                                                                   \
+        *(sz) = 0;                                                                     \
+        OPAL_PMIX_CONVERT_NAME(&_proc, (p));                                           \
+        PMIX_INFO_LOAD(&_info, PMIX_OPTIONAL, NULL, PMIX_BOOL);                        \
+        (r) = PMIx_Get(&(_proc), (s), &(_info), 1, &(_kv));                            \
+        if (NULL == _kv) {                                                             \
+            (r) = PMIX_ERR_NOT_FOUND;                                                  \
+        } else if (PMIX_SUCCESS == (r)) {                                              \
+            *(d) = (uint8_t*)_kv->data.bo.bytes;                                       \
+            *(sz) = _kv->data.bo.size;                                                 \
+            _kv->data.bo.bytes = NULL; /* protect the data */                          \
+        }                                                                              \
+        if (NULL != _kv) {                                                             \
+            PMIX_VALUE_RELEASE(_kv);                                                   \
+        }                                                                              \
+    } while(0);
+
 /**
  * Provide a simplified macro for retrieving modex data
  * from another process: