Add OMPT events for the OpenMP taskwait construct.

[protze.joachim]

Summary

This patch adds the implementation of OMPT tracing events for openMP taskwait constructs.

[jlpeyton]

This LGTM, but I would like John to give the final ok.

[jmellorcrummey]

It appears that no context is available for the diffs. Without the context, I can't tell whether the additions are appropriate or not. The callbacks are intended to monitor the beginning and end of an episode of waiting. There is no evidence of the waiting in the diffs provided without context.

Please prepare the diffs using "git diff -U999999 other-branch" and update the diffs for this patch.

[protze.joachim]

Replaced the diff by a full differential.

[protze.joachim]

In D14383#284083, @jmellorcrummey wrote:

The callbacks are intended to monitor the beginning and end of an episode of waiting. There is no evidence of the waiting in the diffs provided without context.

Please notice, the callbacks implemented here are NOT ompt_event_WAIT_taskwait_begin/end.
The callbacks implemented here just mark the event of reaching / leaving the OpenMP taskwait region, associated to a taskwait construct.

[jmellorcrummey]

I apologize that I misunderstood begin/end pair being implemented when I initially reviewed the patch.

With the context provided, the patch looks good to me.

[jlpeyton]

Manually closing. I forgot to add the Differential Revision: line in the commit message.

runtime/src/kmp_tasking.c

__kmpc_omp_taskwait( ident_t *loc_ref, kmp_int32 gtid )
     KA_TRACE(10, ("__kmpc_omp_taskwait(enter): T#%d loc=%p\n",
                   gtid, loc_ref) );
 
     if ( __kmp_tasking_mode != tskm_immediate_exec ) {
         // GEH TODO: shouldn't we have some sort of OMPRAP API calls here to mark begin wait?
 
         thread = __kmp_threads[ gtid ];
         taskdata = thread -> th.th_current_task;
+
+#if OMPT_SUPPORT && OMPT_TRACE
+        ompt_task_id_t my_task_id;
+        ompt_parallel_id_t my_parallel_id;
+        
+        if (ompt_enabled) {
+            kmp_team_t *team = thread->th.th_team;
+            my_task_id = taskdata->ompt_task_info.task_id;
+            my_parallel_id = team->t.ompt_team_info.parallel_id;
+            
+            if (ompt_callbacks.ompt_callback(ompt_event_taskwait_begin)) {
+                ompt_callbacks.ompt_callback(ompt_event_taskwait_begin)(
+                                my_parallel_id, my_task_id);
+            }
+        }
+#endif
+
 #if USE_ITT_BUILD
         // Note: These values are used by ITT events as well.
 #endif /* USE_ITT_BUILD */
         taskdata->td_taskwait_counter += 1;
         taskdata->td_taskwait_ident    = loc_ref;
         taskdata->td_taskwait_thread   = gtid + 1;
 
 #if USE_ITT_BUILD
#endif
         }
 #if USE_ITT_BUILD
         if ( itt_sync_obj != NULL )
             __kmp_itt_taskwait_finished( gtid, itt_sync_obj );
 #endif /* USE_ITT_BUILD */
 
         // GEH TODO: shouldn't we have some sort of OMPRAP API calls here to mark end of wait?
         taskdata->td_taskwait_thread = - taskdata->td_taskwait_thread;
+
+#if OMPT_SUPPORT && OMPT_TRACE
+        if (ompt_enabled &&
+            ompt_callbacks.ompt_callback(ompt_event_taskwait_end)) {
+            ompt_callbacks.ompt_callback(ompt_event_taskwait_end)(
+                                my_parallel_id, my_task_id);
+        }
+#endif
     }
 
     KA_TRACE(10, ("__kmpc_omp_taskwait(exit): T#%d task %p finished waiting, "
                   "returning TASK_CURRENT_NOT_QUEUED\n", gtid, taskdata) );
 
     return TASK_CURRENT_NOT_QUEUED;
 }
 

runtime/src/ompt-event-specific.h

 #define ompt_event_workshare_end_implemented            ompt_event_UNIMPLEMENTED
 
 #define ompt_event_master_begin_implemented             ompt_event_MAY_ALWAYS_TRACE
 #define ompt_event_master_end_implemented               ompt_event_MAY_ALWAYS_TRACE
 
 #define ompt_event_barrier_begin_implemented            ompt_event_MAY_ALWAYS_TRACE
 #define ompt_event_barrier_end_implemented              ompt_event_MAY_ALWAYS_TRACE
 
-#define ompt_event_taskwait_begin_implemented           ompt_event_UNIMPLEMENTED
-#define ompt_event_taskwait_end_implemented             ompt_event_UNIMPLEMENTED
+#define ompt_event_taskwait_begin_implemented           ompt_event_MAY_ALWAYS_TRACE
+#define ompt_event_taskwait_end_implemented             ompt_event_MAY_ALWAYS_TRACE
 
 #define ompt_event_taskgroup_begin_implemented          ompt_event_UNIMPLEMENTED
 #define ompt_event_taskgroup_end_implemented            ompt_event_UNIMPLEMENTED
 
 #define ompt_event_release_nest_lock_prev_implemented   ompt_event_MAY_ALWAYS_TRACE
 #define ompt_event_wait_lock_implemented                ompt_event_UNIMPLEMENTED
 #define ompt_event_wait_nest_lock_implemented           ompt_event_UNIMPLEMENTED
 #define ompt_event_wait_critical_implemented            ompt_event_UNIMPLEMENTED