message: VLOG(1) the number of times we executed the MarkForCompilationPass inner loop
  This intended to help us detect whether we're observing superlinear behavior in
  practice.
diff: @@ -830,6 +830,8 @@ Status MarkForCompilationPassImpl::Run() {
  std::deque<UnionFind<Cluster>*> worklist;
  BuildInitialClusterSet(compilation_candidates, &clusters, &worklist);
  + int64 iteration_count = 0;
  +
  // Repeatedly contract edges between clusters that are on the same device,
  // provided the contraction would not create a cycle.
  //
  @@ -854,6 +856,7 @@ Status MarkForCompilationPassImpl::Run() {
  }
  for (int to : cycles.Successors(from)) {
  + iteration_count++;
  if (to >= graph_->num_node_ids()) {
  // Node is a fictitious node that is present only in the cycle detection
  // graph. No clustering is possible.
  @@ -926,6 +929,11 @@ Status MarkForCompilationPassImpl::Run() {
  }
  }
  + VLOG(1) << iteration_count << " iterations in inner loop for graph with "
  + << compilation_candidates.size()
  + << " compilation candidates. Iterations per compilation candidate: "
  + << ((1.0 * iteration_count) / compilation_candidates.size());
  +
  // Count the number of non-trivial elements in each cluster.
  std::vector<int> effective_cluster_sizes(graph_->num_node_ids());
  