group: add builtin MPIR_GROUP_{WORLD,SELF}

Add builtin MPIR_GROUP_WORLD and MPIR_GROUP_SELF, so we can create builtin communicators from builtin groups.
pmodels · Dec 12, 2024 · e0c851e · e0c851e
1 parent 09b119a
commit e0c851e
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Showing 4 changed files with 39 additions and 7 deletions.
diff --git a/src/include/mpir_group.h b/src/include/mpir_group.h
@@ -43,6 +43,13 @@
 
  S*/
 
+/* In addition to MPI_GROUP_EMPTY, internally we have a few more builtins */
+#define MPIR_GROUP_WORLD  ((MPI_Group)0x48000001)
+#define MPIR_GROUP_SELF   ((MPI_Group)0x48000002)
+
+#define MPIR_GROUP_WORLD_PTR (MPIR_Group_builtin + 1)
+#define MPIR_GROUP_SELF_PTR  (MPIR_Group_builtin + 2)
+
 /* Worlds -
  * We need a device-independent way of identifying processes. Assuming the concept of
  * "worlds", we can describe a process with (world_idx, world_rank).

diff --git a/src/include/mpir_objects.h b/src/include/mpir_objects.h
@@ -210,7 +210,7 @@ const char *MPIR_Handle_get_kind_str(int kind);
 #define MPIR_COMM_PREALLOC 8
 #endif
 
-#define MPIR_GROUP_N_BUILTIN 1
+#define MPIR_GROUP_N_BUILTIN 3
 #ifdef MPID_GROUP_PREALLOC
 #define MPIR_GROUP_PREALLOC MPID_GROUP_PREALLOC
 #else

diff --git a/src/mpi/group/group_impl.c b/src/mpi/group/group_impl.c
@@ -438,12 +438,11 @@ int MPIR_Group_from_session_pset_impl(MPIR_Session * session_ptr, const char *ps
     int mpi_errno = MPI_SUCCESS;
 
     if (MPL_stricmp(pset_name, "mpi://WORLD") == 0) {
-        mpi_errno = MPIR_Group_create_stride(MPIR_Process.size, MPIR_Process.rank, session_ptr,
-                                             0, 1, 1, new_group_ptr);
-        MPIR_ERR_CHECK(mpi_errno);
+        *new_group_ptr = MPIR_GROUP_WORLD_PTR;
+        MPIR_Group_add_ref(*new_group_ptr);
     } else if (MPL_stricmp(pset_name, "mpi://SELF") == 0) {
-        mpi_errno = MPIR_Group_create_stride(1, 0, session_ptr, 0, 1, 1, new_group_ptr);
-        MPIR_ERR_CHECK(mpi_errno);
+        *new_group_ptr = MPIR_GROUP_SELF_PTR;
+        MPIR_Group_add_ref(*new_group_ptr);
     } else {
         /* TODO: Implement pset struct, locate pset struct ptr */
         MPIR_ERR_SETANDSTMT(mpi_errno, MPI_ERR_ARG, goto fn_fail, "**psetinvalidname");

diff --git a/src/mpi/group/grouputil.c b/src/mpi/group/grouputil.c
@@ -48,7 +48,9 @@ int MPIR_Group_init(void)
 {
     int mpi_errno = MPI_SUCCESS;
 
-    MPIR_Assert(MPIR_GROUP_N_BUILTIN == 1);     /* update this func if this ever triggers */
+    MPIR_Assert(MPIR_GROUP_N_BUILTIN == 3);     /* update this func if this ever triggers */
+
+    struct MPIR_Pmap *pmap;
 
     MPIR_Group_builtin[0].handle = MPI_GROUP_EMPTY;
     MPIR_Object_set_ref(&MPIR_Group_builtin[0], 1);
@@ -57,6 +59,30 @@ int MPIR_Group_init(void)
     MPIR_Group_builtin[0].session_ptr = NULL;
     memset(&MPIR_Group_builtin[0].pmap, 0, sizeof(struct MPIR_Pmap));
 
+    MPIR_Group_builtin[1].handle = MPIR_GROUP_WORLD;
+    MPIR_Object_set_ref(&MPIR_Group_builtin[1], 1);
+    MPIR_Group_builtin[1].size = MPIR_Process.size;
+    MPIR_Group_builtin[1].rank = MPIR_Process.rank;
+    MPIR_Group_builtin[1].session_ptr = NULL;
+    pmap = &MPIR_Group_builtin[1].pmap;
+    pmap->size = MPIR_Process.size;
+    pmap->use_map = false;
+    pmap->u.stride.offset = 0;
+    pmap->u.stride.stride = 1;
+    pmap->u.stride.blocksize = 1;
+
+    MPIR_Group_builtin[2].handle = MPIR_GROUP_SELF;
+    MPIR_Object_set_ref(&MPIR_Group_builtin[2], 1);
+    MPIR_Group_builtin[2].size = 1;
+    MPIR_Group_builtin[2].rank = 0;
+    MPIR_Group_builtin[2].session_ptr = NULL;
+    pmap = &MPIR_Group_builtin[2].pmap;
+    pmap->size = MPIR_Process.size;
+    pmap->use_map = false;
+    pmap->u.stride.offset = MPIR_Process.rank;
+    pmap->u.stride.stride = 1;
+    pmap->u.stride.blocksize = 1;
+
     return mpi_errno;
 }