[OpenMP] libomp: implement nteams-var and teams-thread-limit-var ICVs

The change includes OMP_NUM_TEAMS, OMP_TEAMS_THREAD_LIMIT env variables,
omp_set_num_teams, omp_get_max_teams, omp_set_teams_thread_limit,
omp_get_teams_thread_limit routines.

Differential Revision: https://reviews.llvm.org/D95003

openmp/runtime/src/dllexports

@@ -537,6 +537,10 @@ kmp_set_disp_num_buffers                    890
     omp_pause_resource_all                  757
     omp_get_supported_active_levels         758
     omp_fulfill_event                       759
+    omp_set_num_teams                       802
+    omp_get_max_teams                       803
+    omp_set_teams_thread_limit              804
+    omp_get_teams_thread_limit              805
     omp_display_env                         733
     omp_calloc                              776
     omp_realloc                             777

openmp/runtime/src/include/omp.h.var

@@ -442,6 +442,12 @@
 
     extern int __KAI_KMPC_CONVENTION omp_get_supported_active_levels(void);
 
+    /* OpenMP 5.1 */
+    extern void __KAI_KMPC_CONVENTION omp_set_num_teams(int num_teams);
+    extern int __KAI_KMPC_CONVENTION omp_get_max_teams(void);
+    extern void __KAI_KMPC_CONVENTION omp_set_teams_thread_limit(int limit);
+    extern int __KAI_KMPC_CONVENTION omp_get_teams_thread_limit(void);
+
     /* OpenMP 5.1 Display Environment */
     extern void omp_display_env(int verbose);
 

openmp/runtime/src/include/omp_lib.f90.var

@@ -504,6 +504,26 @@
             integer (kind=kmp_size_t_kind) :: omp_capture_affinity
           end function omp_capture_affinity
 
+          subroutine omp_set_num_teams(num_teams) bind(c)
+            use omp_lib_kinds
+            integer (kind=omp_integer_kind), value :: num_teams
+          end subroutine omp_set_num_teams
+
+          function omp_get_max_teams() bind(c)
+            use omp_lib_kinds
+            integer (kind=omp_integer_kind) omp_get_max_teams
+          end function omp_get_max_teams
+
+          subroutine omp_set_teams_thread_limit(thread_limit) bind(c)
+            use omp_lib_kinds
+            integer (kind=omp_integer_kind), value :: thread_limit
+          end subroutine omp_set_teams_thread_limit
+
+          function omp_get_teams_thread_limit() bind(c)
+            use omp_lib_kinds
+            integer (kind=omp_integer_kind) omp_get_teams_thread_limit
+          end function omp_get_teams_thread_limit
+
           subroutine omp_display_env(verbose) bind(c)
             use omp_lib_kinds
             logical (kind=omp_logical_kind), value :: verbose

openmp/runtime/src/include/omp_lib.h.var

@@ -582,6 +582,28 @@
           integer (kind=kmp_size_t_kind) :: omp_capture_affinity
         end function omp_capture_affinity
 
+        subroutine omp_set_num_teams(num_teams) bind(c)
+          import
+          integer (kind=omp_integer_kind), value :: num_teams
+        end subroutine omp_set_num_teams
+
+        function omp_get_max_teams() bind(c)
+          import
+          integer (kind=omp_integer_kind) omp_get_max_teams
+        end function omp_get_max_teams
+
+        subroutine omp_set_teams_thread_limit(thread_limit) bind(c)
+          import
+          use omp_lib_kinds
+          integer (kind=omp_integer_kind), value :: thread_limit
+        end subroutine omp_set_teams_thread_limit
+
+        function omp_get_teams_thread_limit() bind(c)
+          import
+          use omp_lib_kinds
+          integer (kind=omp_integer_kind) omp_get_teams_thread_limit
+        end function omp_get_teams_thread_limit
+
         subroutine omp_display_env(verbose) bind(c)
           import
           logical (kind=omp_logical_kind), value :: verbose

openmp/runtime/src/kmp.h

@@ -3153,6 +3153,8 @@ extern const char *__kmp_speculative_statsfile;
 extern int __kmp_display_env; /* TRUE or FALSE */
 extern int __kmp_display_env_verbose; /* TRUE if OMP_DISPLAY_ENV=VERBOSE */
 extern int __kmp_omp_cancellation; /* TRUE or FALSE */
+extern int __kmp_nteams;
+extern int __kmp_teams_thread_limit;
 
 /* ------------------------------------------------------------------------- */
 
@@ -3847,6 +3849,10 @@ KMP_EXPORT void __kmpc_task_reduction_modifier_fini(ident_t *loc, int gtid,
 KMP_EXPORT kmp_int32 __kmpc_omp_reg_task_with_affinity(
     ident_t *loc_ref, kmp_int32 gtid, kmp_task_t *new_task, kmp_int32 naffins,
     kmp_task_affinity_info_t *affin_list);
+KMP_EXPORT void __kmp_set_num_teams(int num_teams);
+KMP_EXPORT int __kmp_get_max_teams(void);
+KMP_EXPORT void __kmp_set_teams_thread_limit(int limit);
+KMP_EXPORT int __kmp_get_teams_thread_limit(void);
 
 /* Lock interface routines (fast versions with gtid passed in) */
 KMP_EXPORT void __kmpc_init_lock(ident_t *loc, kmp_int32 gtid,

openmp/runtime/src/kmp_ftn_entry.h

@@ -1373,6 +1373,49 @@ void FTN_STDCALL FTN_FULFILL_EVENT(kmp_event_t *event) {
 #endif
 }
 
+// nteams-var per-device ICV
+void FTN_STDCALL FTN_SET_NUM_TEAMS(int KMP_DEREF num_teams) {
+#ifdef KMP_STUB
+// Nothing.
+#else
+  if (!__kmp_init_serial) {
+    __kmp_serial_initialize();
+  }
+  __kmp_set_num_teams(KMP_DEREF num_teams);
+#endif
+}
+int FTN_STDCALL FTN_GET_MAX_TEAMS(void) {
+#ifdef KMP_STUB
+  return 1;
+#else
+  if (!__kmp_init_serial) {
+    __kmp_serial_initialize();
+  }
+  return __kmp_get_max_teams();
+#endif
+}
+// teams-thread-limit-var per-device ICV
+void FTN_STDCALL FTN_SET_TEAMS_THREAD_LIMIT(int KMP_DEREF limit) {
+#ifdef KMP_STUB
+// Nothing.
+#else
+  if (!__kmp_init_serial) {
+    __kmp_serial_initialize();
+  }
+  __kmp_set_teams_thread_limit(KMP_DEREF limit);
+#endif
+}
+int FTN_STDCALL FTN_GET_TEAMS_THREAD_LIMIT(void) {
+#ifdef KMP_STUB
+  return 1;
+#else
+  if (!__kmp_init_serial) {
+    __kmp_serial_initialize();
+  }
+  return __kmp_get_teams_thread_limit();
+#endif
+}
+
 // display environment variables when requested
 void FTN_STDCALL FTN_DISPLAY_ENV(int verbose) {
 #ifndef KMP_STUB

openmp/runtime/src/kmp_ftn_os.h

@@ -135,6 +135,10 @@
 #define FTN_GET_SUPPORTED_ACTIVE_LEVELS omp_get_supported_active_levels
 #define FTN_DISPLAY_ENV omp_display_env
 #define FTN_FULFILL_EVENT omp_fulfill_event
+#define FTN_SET_NUM_TEAMS omp_set_num_teams
+#define FTN_GET_MAX_TEAMS omp_get_max_teams
+#define FTN_SET_TEAMS_THREAD_LIMIT omp_set_teams_thread_limit
+#define FTN_GET_TEAMS_THREAD_LIMIT omp_get_teams_thread_limit
 
 #endif /* KMP_FTN_PLAIN */
 
@@ -259,6 +263,10 @@
 #define FTN_GET_SUPPORTED_ACTIVE_LEVELS omp_get_supported_active_levels_
 #define FTN_DISPLAY_ENV omp_display_env_
 #define FTN_FULFILL_EVENT omp_fulfill_event_
+#define FTN_SET_NUM_TEAMS omp_set_num_teams_
+#define FTN_GET_MAX_TEAMS omp_get_max_teams_
+#define FTN_SET_TEAMS_THREAD_LIMIT omp_set_teams_thread_limit_
+#define FTN_GET_TEAMS_THREAD_LIMIT omp_get_teams_thread_limit_
 
 #endif /* KMP_FTN_APPEND */
 
@@ -381,6 +389,10 @@
 #define FTN_GET_SUPPORTED_ACTIVE_LEVELS OMP_GET_SUPPORTED_ACTIVE_LEVELS
 #define FTN_DISPLAY_ENV OMP_DISPLAY_ENV
 #define FTN_FULFILL_EVENT OMP_FULFILL_EVENT
+#define FTN_SET_NUM_TEAMS OMP_SET_NUM_TEAMS
+#define FTN_GET_MAX_TEAMS OMP_GET_MAX_TEAMS
+#define FTN_SET_TEAMS_THREAD_LIMIT OMP_SET_TEAMS_THREAD_LIMIT
+#define FTN_GET_TEAMS_THREAD_LIMIT OMP_GET_TEAMS_THREAD_LIMIT
 
 #endif /* KMP_FTN_UPPER */
 
@@ -505,6 +517,10 @@
 #define FTN_GET_SUPPORTED_ACTIVE_LEVELS OMP_GET_SUPPORTED_ACTIVE_LEVELS_
 #define FTN_DISPLAY_ENV OMP_DISPLAY_ENV_
 #define FTN_FULFILL_EVENT OMP_FULFILL_EVENT_
+#define FTN_SET_NUM_TEAMS OMP_SET_NUM_TEAMS_
+#define FTN_GET_MAX_TEAMS OMP_GET_MAX_TEAMS_
+#define FTN_SET_TEAMS_THREAD_LIMIT OMP_SET_TEAMS_THREAD_LIMIT_
+#define FTN_GET_TEAMS_THREAD_LIMIT OMP_GET_TEAMS_THREAD_LIMIT_
 
 #endif /* KMP_FTN_UAPPEND */
 

openmp/runtime/src/kmp_global.cpp

@@ -209,6 +209,8 @@ const char *__kmp_speculative_statsfile = "-";
 int __kmp_display_env = FALSE;
 int __kmp_display_env_verbose = FALSE;
 int __kmp_omp_cancellation = FALSE;
+int __kmp_nteams = 0;
+int __kmp_teams_thread_limit = 0;
 
 #if KMP_HAVE_MWAIT || KMP_HAVE_UMWAIT
 int __kmp_user_level_mwait = FALSE;

openmp/runtime/src/kmp_runtime.cpp

@@ -2753,6 +2753,19 @@ int __kmp_get_max_active_levels(int gtid) {
   return thread->th.th_current_task->td_icvs.max_active_levels;
 }
 
+// nteams-var per-device ICV
+void __kmp_set_num_teams(int num_teams) {
+  if (num_teams > 0)
+    __kmp_nteams = num_teams;
+}
+int __kmp_get_max_teams(void) { return __kmp_nteams; }
+// teams-thread-limit-var per-device ICV
+void __kmp_set_teams_thread_limit(int limit) {
+  if (limit > 0)
+    __kmp_teams_thread_limit = limit;
+}
+int __kmp_get_teams_thread_limit(void) { return __kmp_teams_thread_limit; }
+
 KMP_BUILD_ASSERT(sizeof(kmp_sched_t) == sizeof(int));
 KMP_BUILD_ASSERT(sizeof(enum sched_type) == sizeof(int));
 
@@ -7420,8 +7433,13 @@ void __kmp_push_num_teams(ident_t *id, int gtid, int num_teams,
   KMP_DEBUG_ASSERT(num_teams >= 0);
   KMP_DEBUG_ASSERT(num_threads >= 0);
 
-  if (num_teams == 0)
+  if (num_teams == 0) {
-    num_teams = 1; // default number of teams is 1.
+    if (__kmp_nteams > 0) {
+      num_teams = __kmp_nteams;
+    } else {
+      num_teams = 1; // default number of teams is 1.
+    }
+  }
   if (num_teams > __kmp_teams_max_nth) { // if too many teams requested?
     if (!__kmp_reserve_warn) {
       __kmp_reserve_warn = 1;
@@ -7441,7 +7459,11 @@ void __kmp_push_num_teams(ident_t *id, int gtid, int num_teams,
   KMP_DEBUG_ASSERT(__kmp_avail_proc);
   KMP_DEBUG_ASSERT(__kmp_dflt_team_nth);
   if (num_threads == 0) {
-    num_threads = __kmp_avail_proc / num_teams;
+    if (__kmp_teams_thread_limit > 0) {
+      num_threads = __kmp_teams_thread_limit;
+    } else {
+      num_threads = __kmp_avail_proc / num_teams;
+    }
     // adjust num_threads w/o warning as it is not user setting
     // num_threads = min(num_threads, nthreads-var, thread-limit-var)
     // no thread_limit clause specified -  do not change thread-limit-var ICV

openmp/runtime/src/kmp_settings.cpp

@@ -633,6 +633,33 @@ static void __kmp_stg_print_thread_limit(kmp_str_buf_t *buffer,
   __kmp_stg_print_int(buffer, name, __kmp_cg_max_nth);
 } // __kmp_stg_print_thread_limit
 
+// -----------------------------------------------------------------------------
+// OMP_NUM_TEAMS
+static void __kmp_stg_parse_nteams(char const *name, char const *value,
+                                   void *data) {
+  __kmp_stg_parse_int(name, value, 1, __kmp_sys_max_nth, &__kmp_nteams);
+  K_DIAG(1, ("__kmp_nteams == %d\n", __kmp_nteams));
+} // __kmp_stg_parse_nteams
+
+static void __kmp_stg_print_nteams(kmp_str_buf_t *buffer, char const *name,
+                                   void *data) {
+  __kmp_stg_print_int(buffer, name, __kmp_nteams);
+} // __kmp_stg_print_nteams
+
+// -----------------------------------------------------------------------------
+// OMP_TEAMS_THREAD_LIMIT
+static void __kmp_stg_parse_teams_th_limit(char const *name, char const *value,
+                                           void *data) {
+  __kmp_stg_parse_int(name, value, 1, __kmp_sys_max_nth,
+                      &__kmp_teams_thread_limit);
+  K_DIAG(1, ("__kmp_teams_thread_limit == %d\n", __kmp_teams_thread_limit));
+} // __kmp_stg_parse_teams_th_limit
+
+static void __kmp_stg_print_teams_th_limit(kmp_str_buf_t *buffer,
+                                           char const *name, void *data) {
+  __kmp_stg_print_int(buffer, name, __kmp_teams_thread_limit);
+} // __kmp_stg_print_teams_th_limit
+
 // -----------------------------------------------------------------------------
 // KMP_TEAMS_THREAD_LIMIT
 static void __kmp_stg_parse_teams_thread_limit(char const *name,
@@ -5114,6 +5141,10 @@ static kmp_setting_t __kmp_stg_table[] = {
      __kmp_stg_print_thread_limit, NULL, 0, 0},
     {"KMP_TEAMS_THREAD_LIMIT", __kmp_stg_parse_teams_thread_limit,
      __kmp_stg_print_teams_thread_limit, NULL, 0, 0},
+    {"OMP_NUM_TEAMS", __kmp_stg_parse_nteams, __kmp_stg_print_nteams, NULL, 0,
+     0},
+    {"OMP_TEAMS_THREAD_LIMIT", __kmp_stg_parse_teams_th_limit,
+     __kmp_stg_print_teams_th_limit, NULL, 0, 0},
     {"OMP_WAIT_POLICY", __kmp_stg_parse_wait_policy,
      __kmp_stg_print_wait_policy, NULL, 0, 0},
     {"KMP_DISP_NUM_BUFFERS", __kmp_stg_parse_disp_buffers,

openmp/runtime/test/api/omp_nteams_api.c

@@ -0,0 +1,26 @@
+// RUN: %libomp-compile-and-run
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <omp.h>
+
+int main(int argc, char** argv)
+{
+  int iset, iget;
+  iset = 5;
+  omp_set_num_teams(iset);
+  iget = omp_get_max_teams();
+  if (iset != iget) {
+    fprintf(stderr, "error: nteams-var set to %d, getter returned %d\n", iset, iget);
+    exit(1);
+  }
+  iset = 7;
+  omp_set_teams_thread_limit(iset);
+  iget = omp_get_teams_thread_limit();
+  if (iset != iget) {
+    fprintf(stderr, "error: teams-thread-limit-var set to %d, getter returned %d\n", iset, iget);
+    exit(1);
+  }
+  printf("passed\n");
+  return 0;
+}

openmp/runtime/test/api/omp_nteams_api_env.c

@@ -0,0 +1,24 @@
+// RUN: %libomp-compile && env OMP_NUM_TEAMS=5 OMP_TEAMS_THREAD_LIMIT=7 %libomp-run
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <omp.h>
+
+int main(int argc, char** argv)
+{
+  int iset, iget;
+  iset = 5;
+  iget = omp_get_max_teams();
+  if (iset != iget) {
+    fprintf(stderr, "error: nteams-var set to %d, getter returned %d\n", iset, iget);
+    exit(1);
+  }
+  iset = 7;
+  iget = omp_get_teams_thread_limit();
+  if (iset != iget) {
+    fprintf(stderr, "error: teams-thread-limit-var set to %d, getter returned %d\n", iset, iget);
+    exit(1);
+  }
+  printf("passed\n");
+  return 0;
+}

openmp/runtime/test/api/omp_nteams_api_env2.c

@@ -0,0 +1,26 @@
+// RUN: %libomp-compile && env OMP_NUM_TEAMS=5 OMP_TEAMS_THREAD_LIMIT=7 %libomp-run
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <omp.h>
+
+int main(int argc, char** argv)
+{
+  int iset, iget;
+  iset = 4; // should override OMP_NUM_TEAMS=5
+  omp_set_num_teams(iset);
+  iget = omp_get_max_teams();
+  if (iset != iget) {
+    fprintf(stderr, "error: nteams-var set to %d, getter returned %d\n", iset, iget);
+    exit(1);
+  }
+  iset = 6; // should override OMP_TEAMS_THREAD_LIMIT=7
+  omp_set_teams_thread_limit(iset);
+  iget = omp_get_teams_thread_limit();
+  if (iset != iget) {
+    fprintf(stderr, "error: teams-thread-limit-var set to %d, getter returned %d\n", iset, iget);
+    exit(1);
+  }
+  printf("passed\n");
+  return 0;
+}