// Nondeterminism in serialization would not lead to incorrect results, but
  // may cause spurious cache misses.
  TF_ASSIGN_OR_RETURN(uint64 fingerprint, FingerprintGraph(*graph));
  VLOG(1) << "Subgraph fingerprint:" << fingerprint;
  call_def->set_op(absl::StrCat(call_def->op(), "_", fingerprint));
  return absl::OkStatus();
}

}  // namespace

  std::string s;
  if (!SerializeToStringDeterministic(def, &s)) {
    return errors::Internal("Failed to serialize graphdef.");
  }
  return s;
}

absl::StatusOr<uint64> FingerprintGraph(const Graph& graph) {
  TF_ASSIGN_OR_RETURN(std::string serialized,
                      SerializeGraphDeterministic(graph));
  return Hash64(serialized.data(), serialized.size());
}