1 files changed, 46 insertions, 0 deletions
diff --git a/tensorflow/compiler/xla/service/gpu/stream_assignment.h b/tensorflow/compiler/xla/service/gpu/stream_assignment.h
new file mode 100644
index 0000000000..c2df83aaa4
--- /dev/null
+++ b/tensorflow/compiler/xla/service/gpu/stream_assignment.h
@@ -0,0 +1,46 @@
+/* Copyright 2017 The TensorFlow Authors. All Rights Reserved.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+==============================================================================*/
+
+#ifndef TENSORFLOW_COMPILER_XLA_SERVICE_GPU_STREAM_ASSIGNMENT_H_
+#define TENSORFLOW_COMPILER_XLA_SERVICE_GPU_STREAM_ASSIGNMENT_H_
+
+#include "tensorflow/compiler/xla/service/hlo_instruction.h"
+#include "tensorflow/compiler/xla/service/hlo_module.h"
+#include "tensorflow/core/lib/gtl/flatmap.h"
+
+namespace xla {
+namespace gpu {
+
+// This class encapsulates the assignment of GPU streams to each HloInstruction.
+class StreamAssignment {
+ public:
+  int StreamCount() const { return stream_count_; }
+  int StreamNumberForHlo(const HloInstruction& hlo) const;
+  bool HasStreamAssigned(const HloInstruction& hlo) const;
+  // `hlo` needs to outlive this StreamAssignment object.
+  void AssignStreamToHlo(const HloInstruction* hlo, int stream_no);
+
+ private:
+  int stream_count_ = 1;  // At least the main stream.
+  tensorflow::gtl::FlatMap<const HloInstruction*, int> hlo_to_stream_number_;
+};
+
+// Assigns GPU streams to instructions in `module`.
+std::unique_ptr<StreamAssignment> AssignStreams(const HloModule& module);
+
+}  // namespace gpu
+}  // namespace xla
+
+#endif  // TENSORFLOW_COMPILER_XLA_SERVICE_GPU_STREAM_ASSIGNMENT_H_