Record metrics for slow startups

chrome/common/startup_metric_utils.cc

Index: chrome/common/startup_metric_utils.cc
diff --git a/chrome/common/startup_metric_utils.cc b/chrome/common/startup_metric_utils.cc
index 2292fffe77da3a7991b9e62ddff2aac2bfd4150b..e29aaf244c9d0e95e78b26fc2db761c3f01082c4 100644
--- a/chrome/common/startup_metric_utils.cc
+++ b/chrome/common/startup_metric_utils.cc
@@ -4,21 +4,38 @@
 
 #include "chrome/common/startup_metric_utils.h"
 
+#include "base/hash_tables.h"
 #include "base/logging.h"
+#include "base/metrics/histogram.h"
+#include "base/synchronization/lock.h"
+#include "base/sys_info.h"
 #include "base/time.h"
 
 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.
-static volatile bool g_non_browser_ui_displayed = false;
+volatile bool g_non_browser_ui_displayed = false;
 
 const base::Time* MainEntryPointTimeInternal() {
   static base::Time main_start_time = base::Time::Now();
   return &main_start_time;
 }
 
-static bool g_main_entry_time_was_recorded = false;
+typedef base::hash_map<std::string,base::TimeDelta> SubsystemStartupTimeHash;
+
+SubsystemStartupTimeHash* GetSubsystemStartupTimeHash() {
+  static SubsystemStartupTimeHash* slow_startup_time_hash =
+                                    new SubsystemStartupTimeHash;
+  return slow_startup_time_hash;
+}
+
+base::Lock* GetSubsystemStartupTimeHashLock() {
+  static base::Lock* slow_startup_time_hash_lock = new base::Lock;
+  return slow_startup_time_hash_lock;
+}
+
+bool g_main_entry_time_was_recorded = false;
 }  // namespace
 
 namespace startup_metric_utils {
@@ -37,9 +54,64 @@ void RecordMainEntryPointTime() {
   MainEntryPointTimeInternal();
 }
 
+// Return the time recorded by RecordMainEntryPointTime().
 const base::Time MainEntryStartTime() {
   DCHECK(g_main_entry_time_was_recorded);
   return *MainEntryPointTimeInternal();
 }
 
+void OnBrowserStartupComplete() {
+  // Bail if uptime < 7 minutes, to filter out cases where Chrome may have been
+  // autostarted and the machine is under io pressure.
+  const int64 kSevenMinutesInMilliseconds =
+      base::TimeDelta::FromMinutes(7).InMilliseconds();
+  if (base::SysInfo::Uptime() < kSevenMinutesInMilliseconds)
+    return;
+
+  const base::TimeDelta kStartupTimeMin(base::TimeDelta::FromMilliseconds(1));
+  const base::TimeDelta kStartupTimeMax(base::TimeDelta::FromMinutes(5));
+  static const size_t kStartupTimeBuckets(100);
+
+  // The Startup.BrowserMessageLoopStartTime histogram recorded in
+  // chrome_browser_main.cc exhibits instability in the field which limits its
+  // usefulness in all scenarios except when we have a very large sample size.
+  // Attempt to mitigate this with a new metric:
+  // * Measure time from main entry rather than the OS' notion of process start
+  //   time.
+  // * Only measure launches that occur 7 minutes after boot to try to avoid
+  //   cases where Chrome is auto-started and IO is heavily loaded.
+  base::TimeDelta startup_time_from_main_entry =
+      base::Time::Now() - MainEntryStartTime();
+  UMA_HISTOGRAM_LONG_TIMES(
+      "Startup.BrowserMessageLoopStartTimeFromMainEntry",
+      startup_time_from_main_entry);
+
+  // Record histograms for the subsystem times for startups > 10 seconds.
+  const base::TimeDelta kTenSeconds = base::TimeDelta::FromSeconds(10);
+  if (startup_time_from_main_entry < kTenSeconds)
+    return;
+  {
+    base::AutoLock locker(*GetSubsystemStartupTimeHashLock());
+    SubsystemStartupTimeHash* time_hash = GetSubsystemStartupTimeHash();
+    for (SubsystemStartupTimeHash::iterator i = time_hash->begin();
+        i != time_hash->end();
+        ++i) {
+      const std::string histogram_name = i->first;
+      base::Histogram* counter = base::Histogram::FactoryTimeGet(
+          histogram_name,
+          kStartupTimeMin,
+          kStartupTimeMax,
+          kStartupTimeBuckets,
+          base::Histogram::kUmaTargetedHistogramFlag);
+      counter->AddTime(i->second);
+    }
+  }
+}
+
+ScopedSlowStartupUMA::~ScopedSlowStartupUMA() {
+  base::AutoLock locker(*GetSubsystemStartupTimeHashLock());
+  (*GetSubsystemStartupTimeHash())[histogram_name_] =
+      base::TimeTicks::Now() - start_time_;
+}
+
 }  // namespace startup_metric_utils