StatSummarizer: Make it work without needing the GraphDef.

This will allow the StatSummarizer to be instantiated and used
even when the GraphDef is not easily accessible. A consequence of
this is that the BY_DEFINITION_ORDER ordering of stats is no
longer available, but that was deemed acceptable for this change.

Other notables:
- Added a basic C++ unittest for stat_summarizer.
- Added some commentary about caveats about summaries over runs
  that involve GPUs or partitioned graphs. These caveats existed
  in the prior implementation as well.
Change: 146076563

1 files changed, 13 insertions, 6 deletions

diff --git a/tensorflow/core/util/stat_summarizer.h b/tensorflow/core/util/stat_summarizer.h
index 4568fa420b..248266e6d4 100644
--- a/tensorflow/core/util/stat_summarizer.h
+++ b/tensorflow/core/util/stat_summarizer.h
@@ -131,22 +131,31 @@ class StatSummarizerOptions {
   bool show_summary;
 };
 
-// A class intended to make performance analysis easier by collecting StepStats
-// and showing in an easily understandable format where CPU time is being spent.
-// See tensorflow/examples/android/jni/tensorflow_jni.cc for an example usage.
+// A StatSummarizer assists in performance analysis of Graph executions.
+//
+// It summarizes time spent executing (on GPU/CPU), memory used etc. across
+// multiple executions of a single Graph from the StepStats collected during
+// graph execution.
+//
+// See tensorflow/tools/benchmark/benchmark_model.cc for an example usage.
 class StatSummarizer {
  public:
   enum SortingMetric {
     BY_NAME,
-    BY_DEFINITION_ORDER,
     BY_RUN_ORDER,
     BY_TIME,
     BY_MEMORY,
     BY_TYPE,
   };
 
+  explicit StatSummarizer(const StatSummarizerOptions& options);
+
+  // Deprecated: Use StatSummarizer(const StatSummarizerOptions&) instead. The
+  // GraphDef is not needed by the StatSummarizer.
   explicit StatSummarizer(const tensorflow::GraphDef& tensorflow_graph);
 
+  // Deprecated: Use StatSummarizer(const StatSummarizerOptions&) instead.  The
+  // GraphDef is not needed by the StatSummarizer.
   StatSummarizer(const tensorflow::GraphDef& tensorflow_graph,
                  const StatSummarizerOptions& options);
 
@@ -207,9 +216,7 @@ class StatSummarizer {
   Stat<int64> run_total_us_;
   Stat<int64> memory_;
 
-  std::vector<string> nodes_in_def_order_;
   std::map<std::string, Detail> details_;
-  std::map<string, string> node_types_;
   StatSummarizerOptions options_;
 };