[OpenMP] Fix incorrect barrier imbalance reporting in ITTNOTIFY

Exclude nested explicit tasks from timing, only outer level explicit task
counted and its time added to barrier arrive time for the thread.

Differential Revision: https://reviews.llvm.org/D50584

llvm-svn: 340628

2 files changed, 26 insertions, 22 deletions

diff --git a/openmp/runtime/src/kmp_barrier.cpp b/openmp/runtime/src/kmp_barrier.cpp
index e817549fa8d..51c6e3e7e27 100644
--- a/openmp/runtime/src/kmp_barrier.cpp
+++ b/openmp/runtime/src/kmp_barrier.cpp
@@ -1458,8 +1458,8 @@ int __kmp_barrier(enum barrier_type bt, int gtid, int is_split,
     if (__kmp_tasking_mode != tskm_immediate_exec) {
 #if OMP_45_ENABLED
       if (this_thr->th.th_task_team != NULL) {
-        void *itt_sync_obj = NULL;
 #if USE_ITT_NOTIFY
+        void *itt_sync_obj = NULL;
         if (__itt_sync_create_ptr || KMP_ITT_DEBUG) {
           itt_sync_obj = __kmp_itt_barrier_object(gtid, bt, 1);
           __kmp_itt_barrier_starting(gtid, itt_sync_obj);
diff --git a/openmp/runtime/src/kmp_tasking.cpp b/openmp/runtime/src/kmp_tasking.cpp
index 5a4df0c1ea4..d9220c5a2dc 100644
--- a/openmp/runtime/src/kmp_tasking.cpp
+++ b/openmp/runtime/src/kmp_tasking.cpp
@@ -1266,6 +1266,7 @@ kmp_task_t *__kmpc_omp_task_alloc(ident_t *loc_ref, kmp_int32 gtid,
 static void __kmp_invoke_task(kmp_int32 gtid, kmp_task_t *task,
                               kmp_taskdata_t *current_task) {
   kmp_taskdata_t *taskdata = KMP_TASK_TO_TASKDATA(task);
+  kmp_info_t *thread;
 #if OMP_40_ENABLED
   int discard = 0 /* false */;
 #endif
@@ -1293,20 +1294,10 @@ static void __kmp_invoke_task(kmp_int32 gtid, kmp_task_t *task,
   }
 #endif
 
-#if USE_ITT_BUILD && USE_ITT_NOTIFY
-  kmp_uint64 cur_time;
-  if (__kmp_forkjoin_frames_mode == 3) {
-    // Get the current time stamp to measure task execution time to correct
-    // barrier imbalance time
-    cur_time = __itt_get_timestamp();
-  }
-#endif
-
 #if OMPT_SUPPORT
   // For untied tasks, the first task executed only calls __kmpc_omp_task and
   // does not execute code.
   ompt_thread_info_t oldInfo;
-  kmp_info_t *thread;
   if (UNLIKELY(ompt_enabled.enabled)) {
     // Store the threads states and restore them after the task
     thread = __kmp_threads[gtid];
@@ -1334,8 +1325,8 @@ static void __kmp_invoke_task(kmp_int32 gtid, kmp_task_t *task,
   // TODO: check if this sequence can be hoisted above __kmp_task_start
   // if cancellation has been enabled for this run ...
   if (__kmp_omp_cancellation) {
-    kmp_info_t *this_thr = __kmp_threads[gtid];
-    kmp_team_t *this_team = this_thr->th.th_team;
+    thread = __kmp_threads[gtid];
+    kmp_team_t *this_team = thread->th.th_team;
     kmp_taskgroup_t *taskgroup = taskdata->td_taskgroup;
     if ((taskgroup && taskgroup->cancel_request) ||
         (this_team->t.t_cancel_request == cancel_parallel)) {
@@ -1395,6 +1386,21 @@ static void __kmp_invoke_task(kmp_int32 gtid, kmp_task_t *task,
       __ompt_task_start(task, current_task, gtid);
 #endif
 
+#if USE_ITT_BUILD && USE_ITT_NOTIFY
+    kmp_uint64 cur_time;
+    kmp_int32 kmp_itt_count_task =
+        __kmp_forkjoin_frames_mode == 3 && !taskdata->td_flags.task_serial &&
+        current_task->td_flags.tasktype == TASK_IMPLICIT;
+    if (kmp_itt_count_task) {
+      thread = __kmp_threads[gtid];
+      // Time outer level explicit task on barrier for adjusting imbalance time
+      if (thread->th.th_bar_arrive_time)
+        cur_time = __itt_get_timestamp();
+      else
+        kmp_itt_count_task = 0; // thread is not on a barrier - skip timing
+    }
+#endif
+
 #ifdef KMP_GOMP_COMPAT
     if (taskdata->td_flags.native) {
       ((void (*)(void *))(*(task->routine)))(task->shareds);
@@ -1405,6 +1411,13 @@ static void __kmp_invoke_task(kmp_int32 gtid, kmp_task_t *task,
     }
     KMP_POP_PARTITIONED_TIMER();
 
+#if USE_ITT_BUILD && USE_ITT_NOTIFY
+    if (kmp_itt_count_task) {
+      // Barrier imbalance - adjust arrive time with the task duration
+      thread->th.th_bar_arrive_time += (__itt_get_timestamp() - cur_time);
+    }
+#endif
+
 #if OMP_40_ENABLED
   }
 #endif // OMP_40_ENABLED
@@ -1429,15 +1442,6 @@ static void __kmp_invoke_task(kmp_int32 gtid, kmp_task_t *task,
   }
 #endif
 
-#if USE_ITT_BUILD && USE_ITT_NOTIFY
-  // Barrier imbalance - correct arrive time after the task finished
-  if (__kmp_forkjoin_frames_mode == 3) {
-    kmp_info_t *this_thr = __kmp_threads[gtid];
-    if (this_thr->th.th_bar_arrive_time) {
-      this_thr->th.th_bar_arrive_time += (__itt_get_timestamp() - cur_time);
-    }
-  }
-#endif
   KA_TRACE(
       30,
       ("__kmp_invoke_task(exit): T#%d completed task %p, resuming task %p\n",