Cast: Provide more meaningful stats.

media/cast/logging/stats_event_subscriber_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 "base/memory/ref_counted.h"
 #include "base/memory/scoped_ptr.h"
+#include "base/rand_util.h"
 #include "base/test/simple_test_tick_clock.h"
 #include "base/time/tick_clock.h"
 #include "media/cast/cast_environment.h"
 #include "media/cast/logging/logging_defines.h"
 #include "media/cast/logging/stats_event_subscriber.h"
+#include "media/cast/test/fake_receiver_time_offset_estimator.h"
 #include "media/cast/test/fake_single_thread_task_runner.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
+namespace {
+const int kReceiverOffsetSecs = 100;
+}
+
 namespace media {
 namespace cast {
 
 class StatsEventSubscriberTest : public ::testing::Test {
  protected:
   StatsEventSubscriberTest()
-      : testing_clock_(new base::SimpleTestTickClock()),
-        task_runner_(new test::FakeSingleThreadTaskRunner(testing_clock_)),
+      : sender_clock_(new base::SimpleTestTickClock()),
+        task_runner_(new test::FakeSingleThreadTaskRunner(sender_clock_)),
         cast_environment_(new CastEnvironment(
-            scoped_ptr<base::TickClock>(testing_clock_).Pass(),
+            scoped_ptr<base::TickClock>(sender_clock_).Pass(),
             task_runner_,
             task_runner_,
-            task_runner_)) {}
+            task_runner_)),
+        fake_offset_estimator_(
+            base::TimeDelta::FromSeconds(kReceiverOffsetSecs)) {
+    receiver_clock_.Advance(base::TimeDelta::FromSeconds(kReceiverOffsetSecs));
+    cast_environment_->Logging()->AddRawEventSubscriber(
+        &fake_offset_estimator_);
+  }
 
   virtual ~StatsEventSubscriberTest() {
     if (subscriber_.get())
       cast_environment_->Logging()->RemoveRawEventSubscriber(subscriber_.get());
+    cast_environment_->Logging()->RemoveRawEventSubscriber(
+        &fake_offset_estimator_);
+  }
+
+  void AdvanceClocks(base::TimeDelta delta) {
+    sender_clock_->Advance(delta);
+    receiver_clock_.Advance(delta);
   }
 
   void Init(EventMediaType event_media_type) {
     DCHECK(!subscriber_.get());
-    subscriber_.reset(new StatsEventSubscriber(event_media_type));
+    subscriber_.reset(new StatsEventSubscriber(
+        event_media_type, cast_environment_->Clock(), &fake_offset_estimator_));
     cast_environment_->Logging()->AddRawEventSubscriber(subscriber_.get());
   }
 
-  base::SimpleTestTickClock* testing_clock_;  // Owned by CastEnvironment.
+  base::SimpleTestTickClock* sender_clock_;  // Owned by CastEnvironment.
+  base::SimpleTestTickClock receiver_clock_;
   scoped_refptr<test::FakeSingleThreadTaskRunner> task_runner_;
   scoped_refptr<CastEnvironment> cast_environment_;
+  test::FakeReceiverTimeOffsetEstimator fake_offset_estimator_;
   scoped_ptr<StatsEventSubscriber> subscriber_;
 };
 
-TEST_F(StatsEventSubscriberTest, FrameStats) {
-  Init(VIDEO_EVENT);
+TEST_F(StatsEventSubscriberTest, EmptyStats) {
+  Init(VIDEO_EVENT);
+
+  StatsEventSubscriber::StatsMap stats_map;
+  subscriber_->GetStatsInternal(&stats_map);
+
+  EXPECT_TRUE(stats_map.empty());
+}
+
+TEST_F(StatsEventSubscriberTest, Capture) {
+  Init(VIDEO_EVENT);
+
   uint32 rtp_timestamp = 0;
   uint32 frame_id = 0;
   int num_frames = 10;
-  int frame_size = 123;
-  int delay_base_ms = 10;
-  base::TimeTicks now;
+  base::TimeTicks start_time = sender_clock_->NowTicks();
   for (int i = 0; i < num_frames; i++) {
-    now = testing_clock_->NowTicks();
-    cast_environment_->Logging()->InsertFrameEvent(
-        now, kVideoFrameReceived, rtp_timestamp, frame_id);
-    testing_clock_->Advance(base::TimeDelta::FromMilliseconds(30));
-
-    cast_environment_->Logging()->InsertEncodedFrameEvent(
-        now, kVideoFrameEncoded, rtp_timestamp, i, frame_size, true);
-    testing_clock_->Advance(base::TimeDelta::FromMilliseconds(30));
-
+    cast_environment_->Logging()->InsertFrameEvent(sender_clock_->NowTicks(),
+                                                   kVideoFrameCaptured,
+                                                   rtp_timestamp,
+                                                   frame_id);
+
+    AdvanceClocks(base::TimeDelta::FromMilliseconds(30));
+    rtp_timestamp += 90;
+    frame_id++;
+  }
+
+  base::TimeTicks end_time = sender_clock_->NowTicks();
+
+  StatsEventSubscriber::StatsMap stats_map;
+  subscriber_->GetStatsInternal(&stats_map);
+
+  StatsEventSubscriber::StatsMap::iterator it =
+      stats_map.find(StatsEventSubscriber::CAPTURE_FPS);
+  ASSERT_NE(it, stats_map.end());
+
+  base::TimeDelta duration = end_time - start_time;
+  EXPECT_NEAR(
+      it->second,
+      static_cast<double>(num_frames) / duration.InMilliseconds() * 1000,

[miu, 2014/04/18 00:02:03]

Use InMillisecondsF(), not InMilliseconds() throughout this file.  Then, you
should be able to use EXPECT_DOUBLE_EQ(expected, actual) instead of
EXPECT_NEAR() to test your code for numerical stability.

[imcheng, 2014/04/18 18:20:27]

Done.

+      0.05);
+}
+
+TEST_F(StatsEventSubscriberTest, Encode) {
+  Init(VIDEO_EVENT);
+
+  uint32 rtp_timestamp = 0;
+  uint32 frame_id = 0;
+  int num_frames = 10;
+  base::TimeTicks start_time = sender_clock_->NowTicks();
+  int total_size = 0;
+  for (int i = 0; i < num_frames; i++) {
+    int size = 1000 + base::RandInt(-100, 100);
+    total_size += size;
+    cast_environment_->Logging()->InsertFrameEventWithSize(
+        sender_clock_->NowTicks(),
+        kVideoFrameEncoded,
+        rtp_timestamp,
+        frame_id,
+        size);
+
+    AdvanceClocks(base::TimeDelta::FromMilliseconds(30));
+    rtp_timestamp += 90;
+    frame_id++;
+  }
+
+  base::TimeTicks end_time = sender_clock_->NowTicks();
+
+  StatsEventSubscriber::StatsMap stats_map;
+  subscriber_->GetStatsInternal(&stats_map);
+
+  StatsEventSubscriber::StatsMap::iterator it =
+      stats_map.find(StatsEventSubscriber::ENCODE_FPS);
+  ASSERT_NE(it, stats_map.end());
+
+  base::TimeDelta duration = end_time - start_time;
+  EXPECT_NEAR(
+      it->second,
+      static_cast<double>(num_frames) / duration.InMilliseconds() * 1000,
+      0.05);
+
+  it = stats_map.find(StatsEventSubscriber::ENCODE_KBPS);
+  ASSERT_NE(it, stats_map.end());
+
+  EXPECT_NEAR(it->second,
+              static_cast<double>(total_size) / duration.InMilliseconds() * 8,
+              0.05);
+}
+
+TEST_F(StatsEventSubscriberTest, Decode) {
+  Init(VIDEO_EVENT);
+
+  uint32 rtp_timestamp = 0;
+  uint32 frame_id = 0;
+  int num_frames = 10;
+  base::TimeTicks start_time = sender_clock_->NowTicks();
+  for (int i = 0; i < num_frames; i++) {
+    cast_environment_->Logging()->InsertFrameEvent(receiver_clock_.NowTicks(),
+                                                   kVideoFrameDecoded,
+                                                   rtp_timestamp,
+                                                   frame_id);
+
+    AdvanceClocks(base::TimeDelta::FromMilliseconds(30));
+    rtp_timestamp += 90;
+    frame_id++;
+  }
+
+  base::TimeTicks end_time = sender_clock_->NowTicks();
+
+  StatsEventSubscriber::StatsMap stats_map;
+  subscriber_->GetStatsInternal(&stats_map);
+
+  StatsEventSubscriber::StatsMap::iterator it =
+      stats_map.find(StatsEventSubscriber::DECODE_FPS);
+  ASSERT_NE(it, stats_map.end());
+
+  base::TimeDelta duration = end_time - start_time;
+  EXPECT_NEAR(
+      it->second,
+      static_cast<double>(num_frames) / duration.InMilliseconds() * 1000,
+      0.05);
+}
+
+TEST_F(StatsEventSubscriberTest, PlayoutDelay) {
+  Init(VIDEO_EVENT);
+
+  uint32 rtp_timestamp = 0;
+  uint32 frame_id = 0;
+  int num_frames = 10;
+  int total_delay_ms = 0;
+  for (int i = 0; i < num_frames; i++) {
+    int delay_ms = base::RandInt(-50, 50);
+    base::TimeDelta delay = base::TimeDelta::FromMilliseconds(delay_ms);
+    total_delay_ms += delay_ms;
     cast_environment_->Logging()->InsertFrameEventWithDelay(
-        now,
+        receiver_clock_.NowTicks(),
         kVideoRenderDelay,
         rtp_timestamp,
-        i,
-        base::TimeDelta::FromMilliseconds(i * delay_base_ms));
-    testing_clock_->Advance(base::TimeDelta::FromMilliseconds(30));
-
+        frame_id,
+        delay);
+
+    AdvanceClocks(base::TimeDelta::FromMilliseconds(30));
     rtp_timestamp += 90;
-  }
-
-  // Verify stats.
-  FrameStatsMap frame_stats;
-  subscriber_->GetFrameStats(&frame_stats);
-
-  // Size of stats equals the number of events.
-  EXPECT_EQ(3u, frame_stats.size());
-  FrameStatsMap::const_iterator it = frame_stats.find(kVideoFrameReceived);
-  ASSERT_TRUE(it != frame_stats.end());
-  EXPECT_EQ(num_frames, it->second.event_counter);
-
-  it = frame_stats.find(kVideoFrameEncoded);
-  ASSERT_TRUE(it != frame_stats.end());
-
-  EXPECT_EQ(num_frames * frame_size, static_cast<int>(it->second.sum_size));
-
-  it = frame_stats.find(kVideoRenderDelay);
-  ASSERT_TRUE(it != frame_stats.end());
-
-  EXPECT_EQ(0, it->second.min_delay.InMilliseconds());
-  EXPECT_EQ((num_frames - 1) * delay_base_ms,
-            it->second.max_delay.InMilliseconds());
-  EXPECT_EQ((num_frames - 1) * num_frames / 2 * delay_base_ms,
-            it->second.sum_delay.InMilliseconds());
-}
-
-TEST_F(StatsEventSubscriberTest, PacketStats) {
-  Init(AUDIO_EVENT);
+    frame_id++;
+  }
+
+  StatsEventSubscriber::StatsMap stats_map;
+  subscriber_->GetStatsInternal(&stats_map);
+
+  StatsEventSubscriber::StatsMap::iterator it =
+      stats_map.find(StatsEventSubscriber::AVG_PLAYOUT_DELAY_MS);
+  ASSERT_NE(it, stats_map.end());
+
+  EXPECT_NEAR(
+      it->second, static_cast<double>(total_delay_ms) / num_frames, 0.05);
+}
+
+TEST_F(StatsEventSubscriberTest, E2ELatency) {
+  Init(VIDEO_EVENT);
+
   uint32 rtp_timestamp = 0;
   uint32 frame_id = 0;
+  int num_frames = 10;
+  int total_latency_ms = 0;
+  for (int i = 0; i < num_frames; i++) {
+    cast_environment_->Logging()->InsertFrameEvent(sender_clock_->NowTicks(),
+                                                   kVideoFrameCaptured,
+                                                   rtp_timestamp,
+                                                   frame_id);
+
+    int latency_ms = 100 + base::RandInt(-50, 50);
+    AdvanceClocks(base::TimeDelta::FromMilliseconds(latency_ms));
+
+    int delay_ms = base::RandInt(-50, 50);
+    base::TimeDelta delay = base::TimeDelta::FromMilliseconds(delay_ms);
+    total_latency_ms += latency_ms + delay_ms;
+
+    cast_environment_->Logging()->InsertFrameEventWithDelay(
+        receiver_clock_.NowTicks(),
+        kVideoRenderDelay,
+        rtp_timestamp,
+        frame_id,
+        delay);
+
+    rtp_timestamp += 90;
+    frame_id++;
+  }
+
+  StatsEventSubscriber::StatsMap stats_map;
+  subscriber_->GetStatsInternal(&stats_map);
+
+  StatsEventSubscriber::StatsMap::iterator it =
+      stats_map.find(StatsEventSubscriber::AVG_E2E_LATENCY_MS);
+  ASSERT_NE(it, stats_map.end());
+
+  EXPECT_NEAR(
+      it->second, static_cast<double>(total_latency_ms) / num_frames, 0.05);
+}
+
+TEST_F(StatsEventSubscriberTest, Packets) {
+  Init(VIDEO_EVENT);
+
+  uint32 rtp_timestamp = 0;
   int num_packets = 10;
-  int packet_size = 123;
-  base::TimeTicks first_event_time = testing_clock_->NowTicks();
-  base::TimeTicks now;
+  int num_latency_recorded_packets = 0;
+  base::TimeTicks start_time = sender_clock_->NowTicks();
+  int total_size = 0;
+  int retransmit_total_size = 0;
+  int total_latency_ms = 0;
+  int num_packets_sent = 0;
+  int num_packets_retransmitted = 0;
+  // Every 2nd packet will be retransmitted once.
+  // Every 4th packet will be retransmitted twice.
+  // Every 8th packet will be retransmitted 3 times.
   for (int i = 0; i < num_packets; i++) {
-    now = testing_clock_->NowTicks();
-    cast_environment_->Logging()->InsertPacketEvent(now,
-                                                    kAudioPacketSentToPacer,
+    int size = 1000 + base::RandInt(-100, 100);
+    total_size += size;
+
+    cast_environment_->Logging()->InsertPacketEvent(sender_clock_->NowTicks(),
+                                                    kVideoPacketSentToNetwork,
                                                     rtp_timestamp,
-                                                    frame_id,
                                                     0,
-                                                    10,
-                                                    packet_size);
-    testing_clock_->Advance(base::TimeDelta::FromMilliseconds(30));
-  }
-
-  PacketStatsMap stats_map;
-  subscriber_->GetPacketStats(&stats_map);
-
-  // Size of stats equals the number of event types.
-  EXPECT_EQ(1u, stats_map.size());
-  PacketStatsMap::const_iterator it = stats_map.find(kAudioPacketSentToPacer);
-  ASSERT_NE(stats_map.end(), it);
-
-  EXPECT_EQ(first_event_time, it->second.first_event_time);
-  EXPECT_EQ(now, it->second.last_event_time);
-  EXPECT_EQ(num_packets, it->second.event_counter);
-  EXPECT_EQ(num_packets * packet_size, static_cast<int>(it->second.sum_size));
-}
-
-TEST_F(StatsEventSubscriberTest, GenericStats) {
-  Init(OTHER_EVENT);
-  int num_generic_events = 10;
-  int value = 123;
-  for (int i = 0; i < num_generic_events; i++) {
-    cast_environment_->Logging()->InsertGenericEvent(
-        testing_clock_->NowTicks(), kRttMs, value);
-  }
-
-  GenericStatsMap stats_map;
-  subscriber_->GetGenericStats(&stats_map);
-
-  EXPECT_EQ(1u, stats_map.size());
-  GenericStatsMap::const_iterator it = stats_map.find(kRttMs);
-  ASSERT_NE(stats_map.end(), it);
-
-  EXPECT_EQ(num_generic_events, it->second.event_counter);
-  EXPECT_EQ(num_generic_events * value, it->second.sum);
-  EXPECT_EQ(static_cast<uint64>(num_generic_events * value * value),
-            it->second.sum_squared);
-  EXPECT_LE(value, it->second.min);
-  EXPECT_GE(value, it->second.max);
-}
-
-TEST_F(StatsEventSubscriberTest, Reset) {
-  Init(VIDEO_EVENT);
-  cast_environment_->Logging()->InsertFrameEvent(
-      testing_clock_->NowTicks(), kVideoFrameReceived, 0, 0);
-
-  FrameStatsMap frame_stats;
-  subscriber_->GetFrameStats(&frame_stats);
-  EXPECT_EQ(1u, frame_stats.size());
-
-  subscriber_->Reset();
-  subscriber_->GetFrameStats(&frame_stats);
-  EXPECT_TRUE(frame_stats.empty());
+                                                    i,
+                                                    num_packets - 1,
+                                                    size);
+    num_packets_sent++;
+
+    int latency_ms = 20 + base::RandInt(-10, 10);
+    // Latency is only recorded for packets that aren't retransmitted.
+    if (i % 2 != 0) {
+      total_latency_ms += latency_ms;
+      num_latency_recorded_packets++;
+    }
+
+    AdvanceClocks(base::TimeDelta::FromMilliseconds(latency_ms));
+
+    base::TimeTicks received_time = receiver_clock_.NowTicks();
+
+    // Retransmission 1.
+    AdvanceClocks(base::TimeDelta::FromMilliseconds(10));
+    if (i % 2 == 0) {
+      cast_environment_->Logging()->InsertPacketEvent(
+          receiver_clock_.NowTicks(),
+          kVideoPacketRetransmitted,
+          rtp_timestamp,
+          0,
+          i,
+          num_packets - 1,
+          size);
+      retransmit_total_size += size;
+      num_packets_sent++;
+      num_packets_retransmitted++;
+    }
+
+    // Retransmission 2.
+    AdvanceClocks(base::TimeDelta::FromMilliseconds(10));
+    if (i % 4 == 0) {
+      cast_environment_->Logging()->InsertPacketEvent(
+          receiver_clock_.NowTicks(),
+          kVideoPacketRetransmitted,
+          rtp_timestamp,
+          0,
+          i,
+          num_packets - 1,
+          size);
+      retransmit_total_size += size;
+      num_packets_sent++;
+      num_packets_retransmitted++;
+    }
+
+    // Retransmission 3.
+    AdvanceClocks(base::TimeDelta::FromMilliseconds(10));
+    if (i % 8 == 0) {
+      cast_environment_->Logging()->InsertPacketEvent(
+          receiver_clock_.NowTicks(),
+          kVideoPacketRetransmitted,
+          rtp_timestamp,
+          0,
+          i,
+          num_packets - 1,
+          size);
+      retransmit_total_size += size;
+      num_packets_sent++;
+      num_packets_retransmitted++;
+    }
+
+    cast_environment_->Logging()->InsertPacketEvent(received_time,
+                                                    kVideoPacketReceived,
+                                                    rtp_timestamp,
+                                                    0,
+                                                    i,
+                                                    num_packets - 1,
+                                                    size);
+  }
+
+  base::TimeTicks end_time = sender_clock_->NowTicks();
+  base::TimeDelta duration = end_time - start_time;
+
+  StatsEventSubscriber::StatsMap stats_map;
+  subscriber_->GetStatsInternal(&stats_map);
+
+  // Measure AVG_NETWORK_LATENCY_MS, TRANSMISSION_KBPS, RETRANSMISSION_KBPS,
+  // and PACKET_LOSS_PERCENTAGE.
+  StatsEventSubscriber::StatsMap::iterator it =
+      stats_map.find(StatsEventSubscriber::AVG_NETWORK_LATENCY_MS);
+  ASSERT_NE(it, stats_map.end());
+
+  EXPECT_NEAR(
+      it->second,
+      static_cast<double>(total_latency_ms) / num_latency_recorded_packets,
+      0.05);
+
+  it = stats_map.find(StatsEventSubscriber::TRANSMISSION_KBPS);
+  ASSERT_NE(it, stats_map.end());
+
+  EXPECT_NEAR(it->second,
+              static_cast<double>(total_size) / duration.InMilliseconds() * 8,
+              0.05);
+
+  it = stats_map.find(StatsEventSubscriber::RETRANSMISSION_KBPS);
+  ASSERT_NE(it, stats_map.end());
+
+  EXPECT_NEAR(it->second,
+              static_cast<double>(retransmit_total_size) /
+                  duration.InMilliseconds() * 8,
+              0.05);
+
+  it = stats_map.find(StatsEventSubscriber::PACKET_LOSS_PERCENTAGE);
+  ASSERT_NE(it, stats_map.end());
+
+  EXPECT_NEAR(
+      it->second,
+      static_cast<double>(num_packets_retransmitted) / num_packets_sent * 100,
+      0.05);
 }
 

[miu, 2014/04/18 00:02:03]

Given the issues of precision found in the .cc file, I suggest you add some code
to these unit tests to confirm microsecond-level precision isn't thrown away
(e.g., use AdvanceClocks(base::TimeDelta::FromMicroseconds(12345)), and other
"random pick" values).

[imcheng, 2014/04/18 18:20:27]

I have converted all AdvanceClock args to have sub-milliseconds.

 }  // namespace cast
 }  // namespace media