955e356e4c
Instead of having one stream for compute, host-to-device and device-to-host transfers, switch to having separate streams, just like the GPU does. Add a se::Event field to XlaTensor to allow accurate inter-stream dependencies to be created. As part of this: - Fix TransferManager::TransferLiteralFrom/ToDevice to correctly make generated substreams wait on their master stream. - Fix Stream::BlockHostUntilDone() to not block on or return substreams. This behavior is completely broken and not only nondeterministically returns substreams to the pool but causes indefinite hangs with the HostStream. PiperOrigin-RevId: 203726543
84 lines
2.6 KiB
C++
84 lines
2.6 KiB
C++
/* Copyright 2015 The TensorFlow Authors. All Rights Reserved.
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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==============================================================================*/
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#ifndef TENSORFLOW_STREAM_EXECUTOR_EVENT_H_
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#define TENSORFLOW_STREAM_EXECUTOR_EVENT_H_
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#include <memory>
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#include "tensorflow/stream_executor/platform/port.h"
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namespace stream_executor {
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namespace internal {
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class EventInterface;
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}
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class Stream;
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class StreamExecutor;
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// The Event class, when supported by a platform, enables low-overhead status
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// reporting for a Stream. An Event is inserted at a location in a stream via
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// the Stream::ThenRecordEvent() API. From then on, the Event's status can be
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// monitored via the nonblocking Event::PollForStatus() call.
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class Event {
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public:
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// Potential states for an Event. If PollForStatus() returns anything aside
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// from kPending or kComplete, an error has occurred; kUnknown is a bad state.
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// Not all implementations are able to return all enumeration values. Refer to
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// the platform-specific implementation for details.
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enum class Status {
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kUnknown,
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kError,
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kPending,
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kComplete,
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};
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explicit Event(StreamExecutor* stream_exec); // NOLINT
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// Releases any resources held by the Event object.
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~Event();
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// Performs any platform-specific or potentially error-generating
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// initialization.
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bool Init();
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// Returns the current Status for the event.
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Status PollForStatus();
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// Returns a pointer to the underlying platform-specific implementation.
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internal::EventInterface* implementation() { return implementation_.get(); }
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Event(Event&&) = default;
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Event& operator=(Event&&) = default;
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private:
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friend class Stream;
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// Pointer to the StreamExecutor interface used to create this object.
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// Not owned.
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StreamExecutor* stream_exec_;
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// Pointer to the platform-specific EventInterface implementation underlying
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// the object. Owned.
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std::unique_ptr<internal::EventInterface> implementation_;
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SE_DISALLOW_COPY_AND_ASSIGN(Event);
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};
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} // namespace stream_executor
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#endif // TENSORFLOW_STREAM_EXECUTOR_EVENT_H_
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