message: [tf.data] Add vlog to record how much time each optimization step takes.
diff: @@ -219,8 +219,13 @@ class ModelDatasetOp::Dataset : public DatasetBase {
  tf_shared_lock l(mu_);
  model_input_time = SelfInputTime();
  }
  +
  + int64 optimization_start_us = EnvTime::NowMicros();
  model_->Optimize(dataset()->algorithm_, cpu_budget_, ram_budget_,
  /*model_input_time=*/0);
  + VLOG(2) << "Optimized for "
  + << (EnvTime::NowMicros() - optimization_start_us) << " us.";
  +
  // Exponentially increase the period of running the optimization
  // until a threshold is reached.
  if (optimization_period_ms != kOptimizationPeriodThresholdMs) {
  