cc metrics: Some code cleanup.

. Use indexed initializer when specifying the names for types. . Avoid unnecessary construction of a std::string out of a const char*. . Keep the list of sequence-types alphabetically sorted. BUG=none Change-Id: I8261c3ef3b1e5ab830042ad788f9fb2dc0810a9c Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1811197 Commit-Queue: Sadrul Chowdhury <sadrul@chromium.org> Reviewed-by: Behdad Bakhshinategh <behdadb@chromium.org> Cr-Commit-Position: refs/heads/master@{#698149}
marcosholgado · Sep 19, 2019 · 5488de7 · 5488de7
1 parent 2bd930f
commit 5488de7
Show file tree

Hide file tree

Showing 3 changed files with 35 additions and 19 deletions.
diff --git a/cc/metrics/compositor_frame_reporter.cc b/cc/metrics/compositor_frame_reporter.cc
@@ -15,27 +15,34 @@
 namespace cc {
 namespace {
 
+using StageType = CompositorFrameReporter::StageType;
+
 constexpr int kMissedFrameReportTypeCount =
     static_cast<int>(CompositorFrameReporter::MissedFrameReportTypes::
                          kMissedFrameReportTypeCount);
-constexpr int kStageTypeCount =
-    static_cast<int>(CompositorFrameReporter::StageType::kStageTypeCount);
+constexpr int kStageTypeCount = static_cast<int>(StageType::kStageTypeCount);
 // For each possible FrameSequenceTrackerType there will be a UMA histogram
 // plus one for general case.
 constexpr int kFrameSequenceTrackerTypeCount =
     static_cast<int>(FrameSequenceTrackerType::kMaxType) + 1;
 
 // Names for CompositorFrameReporter::StageType, which should be updated in case
 // of changes to the enum.
-constexpr const char* kStageNames[]{
-    "BeginImplFrameToSendBeginMainFrame",
-    "SendBeginMainFrameToCommit",
-    "Commit",
-    "EndCommitToActivation",
-    "Activation",
-    "EndActivateToSubmitCompositorFrame",
-    "SubmitCompositorFrameToPresentationCompositorFrame",
-    "TotalLatency"};
+constexpr const char* kStageNames[] = {
+    [static_cast<int>(StageType::kBeginImplFrameToSendBeginMainFrame)] =
+        "BeginImplFrameToSendBeginMainFrame",
+    [static_cast<int>(StageType::kSendBeginMainFrameToCommit)] =
+        "SendBeginMainFrameToCommit",
+    [static_cast<int>(StageType::kCommit)] = "Commit",
+    [static_cast<int>(StageType::kEndCommitToActivation)] =
+        "EndCommitToActivation",
+    [static_cast<int>(StageType::kActivation)] = "Activation",
+    [static_cast<int>(StageType::kEndActivateToSubmitCompositorFrame)] =
+        "EndActivateToSubmitCompositorFrame",
+    [static_cast<int>(
+        StageType::kSubmitCompositorFrameToPresentationCompositorFrame)] =
+        "SubmitCompositorFrameToPresentationCompositorFrame",
+    [static_cast<int>(StageType::kTotalLatency)] = "TotalLatency"};
 static_assert(sizeof(kStageNames) / sizeof(kStageNames[0]) == kStageTypeCount,
               "Compositor latency stages has changed.");
 
@@ -61,12 +68,14 @@ constexpr int kHistogramBucketCount = 50;
 std::string HistogramName(const int report_type_index,
                           const int frame_sequence_tracker_type_index,
                           const int stage_type_index) {
-  std::string tracker_type_name = FrameSequenceTracker::
+  DCHECK_LE(frame_sequence_tracker_type_index,
+            FrameSequenceTrackerType::kMaxType);
+  const char* tracker_type_name = FrameSequenceTracker::
       kFrameSequenceTrackerTypeNames[frame_sequence_tracker_type_index];
-  if (!tracker_type_name.empty())
-    tracker_type_name += ".";
+  DCHECK(tracker_type_name);
   return base::StrCat({"CompositorLatency.",
                        kReportTypeNames[report_type_index], tracker_type_name,
+                       *tracker_type_name ? "." : "",
                        kStageNames[stage_type_index]});
 }
 }  // namespace

diff --git a/cc/metrics/frame_sequence_tracker.cc b/cc/metrics/frame_sequence_tracker.cc
@@ -17,9 +17,16 @@
 
 namespace cc {
 
-const char* const FrameSequenceTracker::kFrameSequenceTrackerTypeNames[] = {
-    "CompositorAnimation", "MainThreadAnimation", "PinchZoom", "RAF",
-    "TouchScroll",         "WheelScroll",         "Universal", ""};
+constexpr const char* FrameSequenceTracker::kFrameSequenceTrackerTypeNames[] = {
+    [FrameSequenceTrackerType::kCompositorAnimation] = "CompositorAnimation",
+    [FrameSequenceTrackerType::kMainThreadAnimation] = "MainThreadAnimation",
+    [FrameSequenceTrackerType::kPinchZoom] = "PinchZoom",
+    [FrameSequenceTrackerType::kRAF] = "RAF",
+    [FrameSequenceTrackerType::kTouchScroll] = "TouchScroll",
+    [FrameSequenceTrackerType::kUniversal] = "Universal",
+    [FrameSequenceTrackerType::kWheelScroll] = "WheelScroll",
+    [FrameSequenceTrackerType::kMaxType] = "",
+};
 
 namespace {
 

diff --git a/cc/metrics/frame_sequence_tracker.h b/cc/metrics/frame_sequence_tracker.h
@@ -39,8 +39,8 @@ enum FrameSequenceTrackerType {
   kPinchZoom = 2,
   kRAF = 3,
   kTouchScroll = 4,
-  kWheelScroll = 5,
-  kUniversal = 6,
+  kUniversal = 5,
+  kWheelScroll = 6,
   kMaxType
 };