[XLA:GPU] Remove unused Thunk::ShouldBlockFutureThunks function.

PiperOrigin-RevId: 196206896

1 files changed, 1 insertions, 23 deletions

diff --git a/tensorflow/compiler/xla/service/gpu/gpu_executable.cc b/tensorflow/compiler/xla/service/gpu/gpu_executable.cc
index 04b4f7aef1..e09bee0b94 100644
--- a/tensorflow/compiler/xla/service/gpu/gpu_executable.cc
+++ b/tensorflow/compiler/xla/service/gpu/gpu_executable.cc
@@ -164,9 +164,6 @@ Status GpuExecutable::ExecuteThunks(
                                 sub_streams, hlo_module_->entry_computation());
   uint64 start_micros = tensorflow::Env::Default()->NowMicros();
 
-  // The next event enqueued on stream N must not run until the thunk at
-  // last_blocking_thunk_for_stream[N] completes.
-  std::map<int32, const Thunk*> last_blocking_thunk_for_stream;
   std::map<const Thunk*, std::unique_ptr<se::Event>> thunk_to_finish_event;
   for (Thunk* thunk : thunk_schedule_->TotalOrder()) {
     TF_RETURN_IF_ERROR(thunk->Initialize(*this));
@@ -179,18 +176,10 @@ Status GpuExecutable::ExecuteThunks(
       stream->ThenWaitFor(FindOrDie(thunk_to_finish_event, dependency).get());
     }
 
-    if (last_blocking_thunk_for_stream.count(stream_no)) {
-      stream->ThenWaitFor(FindOrDie(thunk_to_finish_event,
-                                    last_blocking_thunk_for_stream[stream_no])
-                              .get());
-      last_blocking_thunk_for_stream.erase(stream_no);
-    }
-
     // If this thunk requests it, wait for all currently-executing thunks to
     // finish.  This is useful e.g. if the thunk is about to perform autotuning.
     if (thunk->ShouldHaltAllActivityBeforeRunning(stream)) {
       TF_RETURN_IF_ERROR(main_stream->BlockHostUntilDone());
-      last_blocking_thunk_for_stream.clear();
     }
 
     profiler.StartOperation();
@@ -198,22 +187,11 @@ Status GpuExecutable::ExecuteThunks(
             << thunk->hlo_instruction()->ToString() << " on stream "
             << stream_no;
     TF_RETURN_IF_ERROR(thunk->ExecuteOnStream(buffer_allocations, stream));
-    if (thunk_schedule_->Depended(thunk) || thunk->ShouldBlockFutureThunks()) {
+    if (thunk_schedule_->Depended(thunk)) {
       auto finish_event = MakeUnique<se::Event>(main_stream->parent());
       finish_event->Init();
       stream->ThenRecordEvent(finish_event.get());
       thunk_to_finish_event[thunk] = std::move(finish_event);
-
-      if (thunk->ShouldBlockFutureThunks()) {
-        // Set last_blocking_thunk_for_stream on all streams other than this one
-        // so that all other streams will wait for this thunk to complete before
-        // executing any events that occur later in the total order.
-        for (int32 i = 0; i < sub_streams.size() + 1; ++i) {
-          if (i != stream_no) {
-            last_blocking_thunk_for_stream[i] = thunk;
-          }
-        }
-      }
     }
     profiler.FinishOperation(thunk->hlo_instruction());
   }