EQT: Record the max queueing time from navigation start to navigation away

third_party/WebKit/Source/platform/scheduler/renderer/renderer_scheduler_impl_unittest.cc

 // Copyright 2014 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 "platform/scheduler/renderer/renderer_scheduler_impl.h"
 
 #include <utility>
 
 #include "base/callback.h"
 #include "base/macros.h"
 #include "base/memory/ptr_util.h"
 #include "base/message_loop/message_loop.h"
 #include "base/run_loop.h"
 #include "base/single_thread_task_runner.h"
+#include "base/test/histogram_tester.h"
 #include "base/test/simple_test_tick_clock.h"
 #include "cc/output/begin_frame_args.h"
 #include "cc/test/ordered_simple_task_runner.h"
 #include "platform/WebTaskRunner.h"
 #include "platform/scheduler/base/real_time_domain.h"
 #include "platform/scheduler/base/test_time_source.h"
 #include "platform/scheduler/child/scheduler_tqm_delegate_for_test.h"
 #include "platform/scheduler/child/scheduler_tqm_delegate_impl.h"
 #include "platform/scheduler/renderer/auto_advancing_virtual_time_domain.h"
 #include "platform/scheduler/renderer/budget_pool.h"
@@ skipping 3913 matching lines @@
   // While the queueing time estimator is locked, we believe the thread to still
   // be unresponsive.
   EXPECT_TRUE(
       scheduler_->MainThreadSeemsUnresponsive(responsiveness_threshold()));
   // Once we've dropped the lock, we realize the main thread is responsive.
   DropQueueingTimeEstimatorLock();
   EXPECT_FALSE(
       scheduler_->MainThreadSeemsUnresponsive(responsiveness_threshold()));
 }
 
+TEST_F(RendererSchedulerImplTest, MaxQueueingTimeMetric) {
+  base::HistogramTester tester;
+  // Start with a long task. The long queueing time of the task will be
+  // ignored because max queueing time is recorded after navigation start

[tdresser, 2017/05/30 13:34:44]

is recorded -> is only recorded

[Liquan (Max) Gu, 2017/05/30 19:57:19]

Done.

+  // (OnCommitProvisionalLoad).
+  AdvanceTimeWithTask(10);
+  // Navigation start
+  scheduler_->OnCommitProvisionalLoad();
+  // The max queueing time of the following task will be recorded.
+  AdvanceTimeWithTask(1);
+  scheduler_->OnCommitProvisionalLoad();
+  // The expected queueing time of 1s task in 1s window is 500ms.
+  tester.ExpectUniqueSample("RendererScheduler.MaxQueueingTime", 500, 1);
+}
+
+void SetQueueingTimeInThread(RendererSchedulerImpl* scheduler,
+                             base::SimpleTestTickClock* clock) {
+  // Navigation of a webpage start.
+  scheduler->OnCommitProvisionalLoad();
+  // Queueing time is recorded with time advanced.
+  clock->Advance(base::TimeDelta::FromSeconds(1));
+}
+
+TEST_F(RendererSchedulerImplTest, MaxQueueingTimeMetricInTwoThreads) {

[tdresser, 2017/05/30 13:34:44]

We're only ever going to be adding EQT information from a single thread, aren't
we?

When we were talking about a test with threading, I think the case we were
talking about was where you want to kill the thread that the Renderer Scheduler
lives on, to simulate the hard shut down case.

If we've tested that case manually, it's probably fine to rely on the testing of
the SingleSampleMetric to verify that works.

[Liquan (Max) Gu, 2017/05/30 19:57:19]

Talked offline with Tim, as SingleSampleMetric already covered multithread, we
don't need to duplicate it here.

+  base::HistogramTester tester;
+
+  default_task_runner_->PostTask(
+      FROM_HERE,
+      base::Bind(&SetQueueingTimeInThread, scheduler_.get(), clock_.get()));
+  RunUntilIdle();
+  // Histogram won't be set until next navigation start.
+  tester.ExpectUniqueSample("RendererScheduler.MaxQueueingTime", 500, 0);
+  scheduler_->OnCommitProvisionalLoad();
+  // The expected queueing time of 1s task in 1s window is 500ms.
+  tester.ExpectUniqueSample("RendererScheduler.MaxQueueingTime", 500, 1);
+}
+
 }  // namespace scheduler
 }  // namespace blink