Add UMA metric: Startup.BrowserMainToRendererMain.

components/startup_metric_utils/browser/startup_metric_utils.cc

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "components/startup_metric_utils/browser/startup_metric_utils.h"
 
 #include "base/containers/hash_tables.h"
 #include "base/environment.h"
 #include "base/lazy_instance.h"
 #include "base/logging.h"
@@ skipping 11 matching lines @@
 
 namespace {
 
 // Mark as volatile to defensively make sure usage is thread-safe.
 // Note that at the time of this writing, access is only on the UI thread.
 volatile bool g_non_browser_ui_displayed = false;
 
 base::LazyInstance<base::Time>::Leaky g_process_creation_time =
     LAZY_INSTANCE_INITIALIZER;
 
-base::LazyInstance<base::Time>::Leaky g_main_entry_point_time =
+base::LazyInstance<base::Time>::Leaky g_browser_main_entry_point_time =
+    LAZY_INSTANCE_INITIALIZER;
+
+base::LazyInstance<base::Time>::Leaky g_renderer_main_entry_point_time =
     LAZY_INSTANCE_INITIALIZER;
 
 StartupTemperature g_startup_temperature = UNCERTAIN_STARTUP_TEMPERATURE;
 
 #if defined(OS_WIN)
 
 // These values are taken from the Startup.BrowserMessageLoopStartHardFaultCount
 // histogram. If the cold start histogram starts looking strongly bimodal it may
 // be because the binary/resource sizes have grown significantly larger than
 // when these values were set. In this case the new values need to be chosen
@@ skipping 240 matching lines @@
       base::TimeDelta::FromMilliseconds(
           (browser_main_entry_time_raw_ms >> 1) & kLower31BitsMask);
 
   // A timestamp is a 64 bit value, yet histograms can only store 32 bits.
   LOCAL_HISTOGRAM_TIMES("Startup.BrowserMainEntryTimeAbsoluteHighWord",
       browser_main_entry_time_raw_ms_high_word);
   LOCAL_HISTOGRAM_TIMES("Startup.BrowserMainEntryTimeAbsoluteLowWord",
       browser_main_entry_time_raw_ms_low_word);
 }
 
+// Record renderer main entry time histogram.
+void RecordRendererMainEntryHistogram() {
+  const base::Time& browser_main_entry_point_time =
+      g_browser_main_entry_point_time.Get();
+  const base::Time& renderer_main_entry_point_time =
+      g_renderer_main_entry_point_time.Get();
+
+  if (!browser_main_entry_point_time.is_null() &&
+      !renderer_main_entry_point_time.is_null()) {
+    UMA_HISTOGRAM_AND_TRACE_WITH_STARTUP_TEMPERATURE(
+        UMA_HISTOGRAM_LONG_TIMES_100, "Startup.BrowserDLLMainToRendererDLLMain",
+        browser_main_entry_point_time, renderer_main_entry_point_time);
+  }
+}
+
 // Environment variable that stores the timestamp when the executable's main()
 // function was entered.
 const char kChromeMainTimeEnvVar[] = "CHROME_MAIN_TIME";
 
 // Returns the time of main entry recorded from RecordExeMainEntryTime.
 base::Time ExeMainEntryPointTime() {
   scoped_ptr<base::Environment> env(base::Environment::Create());
   std::string time_string;
   int64 time_int = 0;
   if (env->GetVar(kChromeMainTimeEnvVar, &time_string) &&
@@ skipping 14 matching lines @@
 }
 
 void RecordStartupProcessCreationTime(const base::Time& time) {
   DCHECK(g_process_creation_time.Get().is_null());
   g_process_creation_time.Get() = time;
   DCHECK(!g_process_creation_time.Get().is_null());
 }
 
 void RecordMainEntryPointTime(const base::Time& time) {
   DCHECK(MainEntryPointTime().is_null());
-  g_main_entry_point_time.Get() = time;
+  g_browser_main_entry_point_time.Get() = time;
   DCHECK(!MainEntryPointTime().is_null());
 }
 
 void RecordExeMainEntryPointTime(const base::Time& time) {
   std::string exe_load_time = base::Int64ToString(time.ToInternalValue());
   scoped_ptr<base::Environment> env(base::Environment::Create());
   env->SetVar(kChromeMainTimeEnvVar, exe_load_time);
 }
 
 void RecordBrowserMainMessageLoopStart(const base::Time& time,
@@ skipping 72 matching lines @@
 void RecordBrowserOpenTabsDelta(const base::TimeDelta& delta) {
   static bool is_first_call = true;
   if (!is_first_call)
     return;
   is_first_call = false;
 
   UMA_HISTOGRAM_WITH_STARTUP_TEMPERATURE(UMA_HISTOGRAM_LONG_TIMES_100,
                                          "Startup.BrowserOpenTabs", delta);
 }
 
+void RecordRendererMainEntryTime(const base::Time& time) {
+  // Record the renderer main entry time, but don't log the UMA metric
+  // immediately because the startup temperature is not known yet.
+  if (!g_renderer_main_entry_point_time.Get().is_null())

[gab, 2015/11/06 18:05:17]

Shouldn't this be a positive check for is_null()? (as-is doesn't this only
overwrite it when it's not null -- i.e., never if it's never set elsewhere?)

[fdoray, 2015/11/09 15:53:56]

Done.

+    g_renderer_main_entry_point_time.Get() = time;
+}
+
 void RecordFirstWebContentsMainFrameLoad(const base::Time& time) {
   static bool is_first_call = true;
   if (!is_first_call || time.is_null())
     return;
   is_first_call = false;
   if (WasNonBrowserUIDisplayed() || g_process_creation_time.Get().is_null())
     return;
 
   UMA_HISTOGRAM_AND_TRACE_WITH_STARTUP_TEMPERATURE(
       UMA_HISTOGRAM_LONG_TIMES_100, "Startup.FirstWebContents.MainFrameLoad2",
@@ skipping 11 matching lines @@
   UMA_HISTOGRAM_WITH_STARTUP_TEMPERATURE(
       UMA_HISTOGRAM_LONG_TIMES_100, "Startup.FirstWebContents.MainFrameLoad",
       time - g_process_creation_time.Get());
 }
 
 void RecordFirstWebContentsNonEmptyPaint(const base::Time& time) {
   static bool is_first_call = true;
   if (!is_first_call || time.is_null())
     return;
   is_first_call = false;
+
+  // At this point, we know the first renderer main entry time and the startup
+  // temperature, so log Startup.BrowserDLLMainToRendererDLLMain.

[gab, 2015/11/06 18:05:17]

Log Startup.BrowserDLLMainToRendererDLLMain now that the first renderer main
entry time and the startup temperature are known.

(i.e. avoid "we" and "so")

[fdoray, 2015/11/09 15:53:56]

Done.

+  RecordRendererMainEntryHistogram();
+
   if (WasNonBrowserUIDisplayed() || g_process_creation_time.Get().is_null())
     return;
 
   UMA_HISTOGRAM_AND_TRACE_WITH_STARTUP_TEMPERATURE(
       UMA_HISTOGRAM_LONG_TIMES_100, "Startup.FirstWebContents.NonEmptyPaint2",
       g_process_creation_time.Get(), time);
 }
 
 void RecordDeprecatedFirstWebContentsNonEmptyPaint(const base::Time& time) {
   static bool is_first_call = true;
@@ skipping 30 matching lines @@
   if (WasNonBrowserUIDisplayed() || g_process_creation_time.Get().is_null())
     return;
 
   UMA_HISTOGRAM_AND_TRACE_WITH_STARTUP_TEMPERATURE(
       UMA_HISTOGRAM_LONG_TIMES_100,
       "Startup.FirstWebContents.MainNavigationFinished",
       g_process_creation_time.Get(), time);
 }
 
 base::Time MainEntryPointTime() {
-  return g_main_entry_point_time.Get();
+  return g_browser_main_entry_point_time.Get();
 }
 
 StartupTemperature GetStartupTemperature() {
   return g_startup_temperature;
 }
 
 }  // namespace startup_metric_utils