message: Set the number of warmup steps for building the cost model.
diff: @@ -140,6 +140,7 @@ static GCluster TF_NewCluster(bool allow_soft_placement,
  timeout_s, num_cpu_cores, num_gpus);
  cluster_->DisableDetailedStats(disable_detailed_stats);
  cluster_->AllowSoftPlacement(allow_soft_placement);
  + cluster_->SetNumWarmupSteps(10);
  tensorflow::Status status = cluster_->Provision();
  tensorflow::Set_TF_Status_from_Status(out_status, status);
  return GCluster(cluster_);
  