Method ReturnSubStream

tensorflow/stream_executor/stream.cc:2575–2608

}

void Stream::ReturnSubStream(Stream *sub_stream) {
  absl::MutexLock lock(&mu_);

  // Look for the sub-stream.
  for (int64 index = 0; index < sub_streams_.size(); ++index) {
    std::pair<std::unique_ptr<Stream>, bool> &pair = sub_streams_[index];
    if (pair.first.get() != sub_stream) {
      continue;
    }

    // Found the sub_stream.
    if (sub_stream->ok()) {
      VLOG(1) << DebugStreamPointers() << " returned ok sub_stream "
              << sub_stream->DebugStreamPointers();
      pair.second = true;
    } else {
      // The returned stream is not ok. Streams have a monotonic state
      // machine; the stream will remain in !ok forever. Swap it with the last
      // stream and pop it off.
      VLOG(1) << DebugStreamPointers() << " returned !ok sub_stream "
              << sub_stream->DebugStreamPointers();
      const int64 last = sub_streams_.size() - 1;
      if (index != last) {
        std::swap(pair, sub_streams_[last]);
      }
      sub_streams_.pop_back();
    }
    return;
  }

  LOG(FATAL) << DebugStreamPointers()
             << " did not create the returned sub-stream "
             << sub_stream->DebugStreamPointers();
}

Stream &Stream::ThenStartTimer(Timer *t) {
  VLOG_CALL(PARAM(t));