Track cc histograms using a global "client name" variable.

BUG=526192
CQ_INCLUDE_TRYBOTS=tryserver.blink:linux_blink_rel

Review URL: https://codereview.chromium.org/1321013004

Cr-Commit-Position: refs/heads/master@{#347565}

6 files changed, 100 insertions, 30 deletions

diff --git a/cc/base/histograms.cc b/cc/base/histograms.cc
index 9fe1515..ba6f4f6 100644
--- a/cc/base/histograms.cc
+++ b/cc/base/histograms.cc
@@ -6,12 +6,51 @@
 
 #include <algorithm>
 #include <cmath>
+#include <cstring>
 #include <limits>
 
+#include "base/lazy_instance.h"
+#include "base/logging.h"
 #include "base/numerics/safe_conversions.h"
+#include "base/synchronization/lock.h"
 
 namespace cc {
 
+// Global data tracking the client name that was set.
+// Both of these variables are protected by the lock.
+static base::LazyInstance<base::Lock>::Leaky g_client_name_lock =
+    LAZY_INSTANCE_INITIALIZER;
+static const char* g_client_name = nullptr;
+static bool g_multiple_client_names_set = false;
+
+void SetClientNameForMetrics(const char* client_name) {
+  base::AutoLock auto_lock(g_client_name_lock.Get());
+
+  // Only warn once.
+  if (g_multiple_client_names_set)
+    return;
+
+  // If a different name is set, return nullptr from now on and log a warning.
+  const char* old_client_name = g_client_name;
+  if (old_client_name && strcmp(old_client_name, client_name)) {
+    g_client_name = nullptr;
+    g_multiple_client_names_set = true;
+    LOG(WARNING) << "Started multiple compositor clients (" << old_client_name
+                 << ", " << client_name
+                 << ") in one process. Some metrics will be disabled.";
+    return;
+  }
+
+  // If the client name is being set for the first time, store it.
+  if (!old_client_name)
+    g_client_name = client_name;
+}
+
+const char* GetClientNameForMetrics() {
+  base::AutoLock auto_lock(g_client_name_lock.Get());
+  return g_client_name;
+}
+
 // Minimum elapsed time of 1us to limit weighting of fast calls.
 static const int64 kMinimumTimeMicroseconds = 1;
 
diff --git a/cc/base/histograms.h b/cc/base/histograms.h
index 0c8a2bc..542ae5d 100644
--- a/cc/base/histograms.h
+++ b/cc/base/histograms.h
@@ -9,38 +9,63 @@
 #include "base/metrics/histogram_base.h"
 #include "base/metrics/histogram_macros.h"
 #include "base/numerics/safe_math.h"
+#include "base/strings/stringprintf.h"
 #include "base/time/time.h"
 #include "base/timer/elapsed_timer.h"
 #include "cc/base/cc_export.h"
 
 namespace cc {
 
+// Supplies a client name to be inserted into histogram names.
+// These are known so far: Renderer, Browser
+//
+// We currently assume that there is only one distinct client per process.
+// Not thread-safe. If called multiple times, warns and skips metrics.
+CC_EXPORT void SetClientNameForMetrics(const char* client_name);
+
+// Returns the client name, for use by applicable cc metrics code.
+// May return null, in which case no clients, or at least two clients, set the
+// client name, and these metrics should be omitted.
+//
+// This method guarantees that it will never return two distinct non-null
+// values over the lifetime of the process.
+const char* GetClientNameForMetrics();
+
 // Emits UMA histogram trackers for time spent as well as area (in pixels)
 // processed per unit time. Time is measured in microseconds, and work in
-// pixels per millisecond.
+// pixels per millisecond. Histogram name should include a %s to grab the client
+// name.
 //
 // Usage:
 //   // Outside of a method, perhaps in a namespace.
-//   DEFINE_SCOPED_UMA_HISTOGRAM_AREA_TIMER(ScopedReticulateSplinesTimer,
-//                                          "ReticulateSplinesUs",
-//                                          "ReticulateSplinesPixelsPerMs");
+//   DEFINE_SCOPED_UMA_HISTOGRAM_AREA_TIMER(
+//       ScopedReticulateSplinesTimer,
+//       "Compositing.%s.ReticulateSplinesUs",
+//       "Compositing.%s.ReticulateSplinesPixelsPerMs");
 //
 //   // Inside a method.
 //   ScopedReticulateSplinesTimer timer;
 //   timer.AddArea(some_rect.size().GetArea());
-#define DEFINE_SCOPED_UMA_HISTOGRAM_AREA_TIMER(class_name, time_histogram, \
-                                               area_histogram)             \
-  class class_name : public ::cc::ScopedUMAHistogramAreaTimerBase {        \
-   public:                                                                 \
-    ~class_name();                                                         \
-  };                                                                       \
-  class_name::~class_name() {                                              \
-    Sample time_sample;                                                    \
-    Sample area_sample;                                                    \
-    if (GetHistogramValues(&time_sample, &area_sample)) {                  \
-      UMA_HISTOGRAM_COUNTS(time_histogram, time_sample);                   \
-      UMA_HISTOGRAM_COUNTS(area_histogram, area_sample);                   \
-    }                                                                      \
+//
+#define DEFINE_SCOPED_UMA_HISTOGRAM_AREA_TIMER(class_name, time_histogram,  \
+                                               area_histogram)              \
+  class class_name : public ::cc::ScopedUMAHistogramAreaTimerBase {         \
+   public:                                                                  \
+    ~class_name();                                                          \
+  };                                                                        \
+  class_name::~class_name() {                                               \
+    Sample time_sample;                                                     \
+    Sample area_sample;                                                     \
+    const char* client_name = ::cc::GetClientNameForMetrics();              \
+    if (client_name && GetHistogramValues(&time_sample, &area_sample)) {    \
+      /* GetClientNameForMetrics only returns one non-null value over */    \
+      /* the lifetime of the process, so these histogram names are */       \
+      /* runtime constant. */                                               \
+      UMA_HISTOGRAM_COUNTS(base::StringPrintf(time_histogram, client_name), \
+                           time_sample);                                    \
+      UMA_HISTOGRAM_COUNTS(base::StringPrintf(area_histogram, client_name), \
+                           area_sample);                                    \
+    }                                                                       \
   }
 
 class CC_EXPORT ScopedUMAHistogramAreaTimerBase {
diff --git a/cc/playback/display_list_recording_source.cc b/cc/playback/display_list_recording_source.cc
index c06fcfa..6bd14ff 100644
--- a/cc/playback/display_list_recording_source.cc
+++ b/cc/playback/display_list_recording_source.cc
@@ -34,8 +34,8 @@ const bool kDefaultClearCanvasSetting = true;
 
 DEFINE_SCOPED_UMA_HISTOGRAM_AREA_TIMER(
     ScopedDisplayListRecordingSourceUpdateTimer,
-    "Compositing.DisplayListRecordingSource.UpdateUs",
-    "Compositing.DisplayListRecordingSource.UpdateInvalidatedAreaPerMs");
+    "Compositing.%s.DisplayListRecordingSource.UpdateUs",
+    "Compositing.%s.DisplayListRecordingSource.UpdateInvalidatedAreaPerMs");
 
 }  // namespace
 
diff --git a/cc/playback/picture_pile.cc b/cc/playback/picture_pile.cc
index bafa0ed..bdb4700 100644
--- a/cc/playback/picture_pile.cc
+++ b/cc/playback/picture_pile.cc
@@ -149,8 +149,8 @@ const bool kDefaultClearCanvasSetting = true;
 
 DEFINE_SCOPED_UMA_HISTOGRAM_AREA_TIMER(
     ScopedPicturePileUpdateTimer,
-    "Compositing.PicturePile.UpdateUs",
-    "Compositing.PicturePile.UpdateInvalidatedAreaPerMs");
+    "Compositing.%s.PicturePile.UpdateUs",
+    "Compositing.%s.PicturePile.UpdateInvalidatedAreaPerMs");
 
 }  // namespace
 
diff --git a/cc/tiles/tile_manager.cc b/cc/tiles/tile_manager.cc
index 7288961..68066ac 100644
--- a/cc/tiles/tile_manager.cc
+++ b/cc/tiles/tile_manager.cc
@@ -33,8 +33,8 @@ const bool kUseColorEstimator = true;
 
 DEFINE_SCOPED_UMA_HISTOGRAM_AREA_TIMER(
     ScopedRasterTaskTimer,
-    "Compositing.RasterTask.RasterUs",
-    "Compositing.RasterTask.RasterPixelsPerMs");
+    "Compositing.%s.RasterTask.RasterUs",
+    "Compositing.%s.RasterTask.RasterPixelsPerMs");
 
 class RasterTaskImpl : public RasterTask {
  public:
diff --git a/cc/trees/layer_tree_host_impl.cc b/cc/trees/layer_tree_host_impl.cc
index f9d115a..7372d1d 100644
--- a/cc/trees/layer_tree_host_impl.cc
+++ b/cc/trees/layer_tree_host_impl.cc
@@ -23,6 +23,7 @@
 #include "cc/animation/scroll_offset_animation_curve.h"
 #include "cc/animation/scrollbar_animation_controller.h"
 #include "cc/animation/timing_function.h"
+#include "cc/base/histograms.h"
 #include "cc/base/math_util.h"
 #include "cc/debug/benchmark_instrumentation.h"
 #include "cc/debug/debug_rect_history.h"
@@ -1022,13 +1023,18 @@ DrawResult LayerTreeHostImpl::PrepareToDraw(FrameData* frame) {
       "Compositing.NumActiveLayers",
       base::saturated_cast<int>(active_tree_->NumLayers()), 1, 400, 20);
 
-  size_t total_picture_memory = 0;
-  for (const PictureLayerImpl* layer : active_tree()->picture_layers())
-    total_picture_memory += layer->GetRasterSource()->GetPictureMemoryUsage();
-  if (total_picture_memory != 0) {
-    UMA_HISTOGRAM_COUNTS(
-        "Compositing.PictureMemoryUsageKb",
-        base::saturated_cast<int>(total_picture_memory / 1024));
+  if (const char* client_name = GetClientNameForMetrics()) {
+    size_t total_picture_memory = 0;
+    for (const PictureLayerImpl* layer : active_tree()->picture_layers())
+      total_picture_memory += layer->GetRasterSource()->GetPictureMemoryUsage();
+    if (total_picture_memory != 0) {
+      // GetClientNameForMetrics only returns one non-null value over the
+      // lifetime of the process, so this histogram name is runtime constant.
+      UMA_HISTOGRAM_COUNTS(
+          base::StringPrintf("Compositing.%s.PictureMemoryUsageKb",
+                             client_name),
+          base::saturated_cast<int>(total_picture_memory / 1024));
+    }
   }
 
   bool update_lcd_text = false;