Method RunOptimizer

tensorflow/core/grappler/optimizers/meta_optimizer.cc:585–649

}

Status MetaOptimizer::RunOptimizer(
    GraphOptimizer* optimizer, Cluster* cluster, GrapplerItem* optimized_item,
    GraphDef* optimized_graph, GraphOptimizationResult* optimization_result) {
  const uint64 start_us = Env::Default()->NowMicros();

  // If optimizer doesn't need a function library, we will replace it with a
  // stub before running optimization, and will put it back at the end.
  FunctionDefLibrary optimized_graph_function_library;
  const bool is_function_library_aware = optimizer->UsesFunctionLibrary();

  // Replace function library in optimized graph with a stub.
  if (!is_function_library_aware) {
    VLOG(3) << "Replace function library with a stub for " << optimizer->name();
    optimized_graph_function_library.Swap(optimized_graph->mutable_library());
    *optimized_graph->mutable_library() =
        GetFunctionDefLibraryStub(optimized_graph_function_library);
  }

  // This swaps the current optimized_graph into optimized item and
  // resets optimized_graph to an empty graph.
  optimized_graph->Swap(&optimized_item->graph);
  *optimized_graph = GraphDef();
  optimizer->set_deadline_usec(this->deadline_usec());
  Status status =
      optimizer->Optimize(cluster, *optimized_item, optimized_graph);
  const uint64 end_us = Env::Default()->NowMicros();
  const float duration_ms = (end_us - start_us) / 1000.0f;

  string message;
  if (!status.ok()) {
    optimized_graph->Swap(&optimized_item->graph);
    if (errors::IsAborted(status)) {
      // By convention we (ab-)use the Aborted error code to signal that the
      // optimizer returned without performing any changes to the graph.
      message = strings::StrCat(optimizer->name(),
                                " did nothing. time = ", duration_ms, "ms.");
      // Swallow the non-critical error.
      status = Status::OK();
    } else if (errors::IsDeadlineExceeded(status)) {
      message =
          strings::StrCat(status.ToString(), ", time = ", duration_ms, "ms.");
      LOG(WARNING) << optimizer->name() << " failed: " << message;
    } else {
      message = status.ToString();
      LOG(ERROR) << optimizer->name() << " failed: " << message;
    }
  } else {
    message = strings::StrCat(
        PrintSizesBeforeAfter(optimized_item->graph, *optimized_graph),
        ", time = ", duration_ms, "ms.");
    VLOG(1) << optimizer->name() << ": " << message;
  }

  // Swap function library back into the main graph.
  if (!is_function_library_aware) {
    optimized_graph->mutable_library()->Swap(&optimized_graph_function_library);
  }