src/media/cast/test/cast_benchmarks.cc

   1 // Copyright 2014 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4 //
   5 // This program benchmarks the theoretical throughput of the cast library.
   6 // It runs using a fake clock, simulated network and fake codecs. This allows
   7 // tests to run much faster than real time.
   8 // To run the program, run:
   9 // $ ./out/Release/cast_benchmarks | tee benchmarkoutput.asc
  10 // This may take a while, when it is done, you can view the data with
  11 // meshlab by running:
  12 // $ meshlab benchmarkoutput.asc
  13 // After starting meshlab, turn on Render->Show Axis. The red axis will
  14 // represent bandwidth (in megabits) the blue axis will be packet drop
  15 // (in percent) and the green axis will be latency (in milliseconds).
  16 //
  17 // This program can also be used for profiling. On linux it has
  18 // built-in support for this. Simply set the environment variable
  19 // PROFILE_FILE before running it, like so:
  20 // $ export PROFILE_FILE=cast_benchmark.profile
  21 // Then after running the program, you can view the profile with:
  22 // $ pprof ./out/Release/cast_benchmarks $PROFILE_FILE --gv
  23
  24 #include <math.h>
  25 #include <stdint.h>
  26
  27 #include <map>
  28 #include <vector>
  29
  30 #include "base/at_exit.h"
  31 #include "base/bind.h"
  32 #include "base/bind_helpers.h"
  33 #include "base/command_line.h"
  34 #include "base/debug/profiler.h"
  35 #include "base/stl_util.h"
  36 #include "base/strings/string_number_conversions.h"
  37 #include "base/strings/stringprintf.h"
  38 #include "base/test/simple_test_tick_clock.h"
  39 #include "base/threading/thread.h"
  40 #include "base/time/tick_clock.h"
  41 #include "media/base/audio_bus.h"
  42 #include "media/base/video_frame.h"
  43 #include "media/cast/cast_config.h"
  44 #include "media/cast/cast_environment.h"
  45 #include "media/cast/cast_receiver.h"
  46 #include "media/cast/cast_sender.h"
  47 #include "media/cast/logging/simple_event_subscriber.h"
  48 #include "media/cast/net/cast_transport_config.h"
  49 #include "media/cast/net/cast_transport_defines.h"
  50 #include "media/cast/net/cast_transport_sender.h"
  51 #include "media/cast/net/cast_transport_sender_impl.h"
  52 #include "media/cast/test/fake_single_thread_task_runner.h"
  53 #include "media/cast/test/loopback_transport.h"
  54 #include "media/cast/test/skewed_single_thread_task_runner.h"
  55 #include "media/cast/test/skewed_tick_clock.h"
  56 #include "media/cast/test/utility/audio_utility.h"
  57 #include "media/cast/test/utility/default_config.h"
  58 #include "media/cast/test/utility/test_util.h"
  59 #include "media/cast/test/utility/udp_proxy.h"
  60 #include "media/cast/test/utility/video_utility.h"
  61 #include "testing/gtest/include/gtest/gtest.h"
  62
  63 namespace media {
  64 namespace cast {
  65
  66 namespace {
  67
  68 static const int64 kStartMillisecond = INT64_C(1245);
  69 static const int kAudioChannels = 2;
  70 static const int kVideoHdWidth = 1280;
  71 static const int kVideoHdHeight = 720;
  72 static const int kTargetPlayoutDelayMs = 300;
  73
  74 // The tests are commonly implemented with |kFrameTimerMs| RunTask function;
  75 // a normal video is 30 fps hence the 33 ms between frames.
  76 static const int kFrameTimerMs = 33;
  77
  78 void UpdateCastTransportStatus(CastTransportStatus status) {
  79   bool result = (status == TRANSPORT_AUDIO_INITIALIZED ||
  80                  status == TRANSPORT_VIDEO_INITIALIZED);
  81   EXPECT_TRUE(result);
  82 }
  83
  84 void AudioInitializationStatus(CastInitializationStatus status) {
  85   EXPECT_EQ(STATUS_AUDIO_INITIALIZED, status);
  86 }
  87
  88 void VideoInitializationStatus(CastInitializationStatus status) {
  89   EXPECT_EQ(STATUS_VIDEO_INITIALIZED, status);
  90 }
  91
  92 void IgnoreRawEvents(const std::vector<PacketEvent>& packet_events,
  93                      const std::vector<FrameEvent>& frame_events) {
  94 }
  95
  96 }  // namespace
  97
  98 // Wraps a CastTransportSender and records some statistics about
  99 // the data that goes through it.
 100 class CastTransportSenderWrapper : public CastTransportSender {
 101  public:
 102   // Takes ownership of |transport|.
 103   void Init(CastTransportSender* transport,
 104             uint64* encoded_video_bytes,
 105             uint64* encoded_audio_bytes) {
 106     transport_.reset(transport);
 107     encoded_video_bytes_ = encoded_video_bytes;
 108     encoded_audio_bytes_ = encoded_audio_bytes;
 109   }
 110
 111   virtual void InitializeAudio(
 112       const CastTransportRtpConfig& config,
 113       const RtcpCastMessageCallback& cast_message_cb,
 114       const RtcpRttCallback& rtt_cb) OVERRIDE {
 115     transport_->InitializeAudio(config, cast_message_cb, rtt_cb);
 116   }
 117
 118   virtual void InitializeVideo(
 119       const CastTransportRtpConfig& config,
 120       const RtcpCastMessageCallback& cast_message_cb,
 121       const RtcpRttCallback& rtt_cb) OVERRIDE {
 122     transport_->InitializeVideo(config, cast_message_cb, rtt_cb);
 123   }
 124
 125   virtual void InsertCodedAudioFrame(
 126       const EncodedFrame& audio_frame) OVERRIDE {
 127     *encoded_audio_bytes_ += audio_frame.data.size();
 128     transport_->InsertCodedAudioFrame(audio_frame);
 129   }
 130
 131   virtual void InsertCodedVideoFrame(
 132       const EncodedFrame& video_frame) OVERRIDE {
 133     *encoded_video_bytes_ += video_frame.data.size();
 134     transport_->InsertCodedVideoFrame(video_frame);
 135   }
 136
 137   virtual void SendSenderReport(
 138       uint32 ssrc,
 139       base::TimeTicks current_time,
 140       uint32 current_time_as_rtp_timestamp) OVERRIDE {
 141     transport_->SendSenderReport(ssrc,
 142                                  current_time,
 143                                  current_time_as_rtp_timestamp);
 144   }
 145
 146   // Retransmission request.
 147   virtual void ResendPackets(
 148       bool is_audio,
 149       const MissingFramesAndPacketsMap& missing_packets,
 150       bool cancel_rtx_if_not_in_list,
 151       base::TimeDelta dedupe_window) OVERRIDE {
 152     transport_->ResendPackets(
 153         is_audio, missing_packets, cancel_rtx_if_not_in_list, dedupe_window);
 154   }
 155
 156   virtual PacketReceiverCallback PacketReceiverForTesting() OVERRIDE {
 157     return transport_->PacketReceiverForTesting();
 158   }
 159
 160  private:
 161   scoped_ptr<CastTransportSender> transport_;
 162   uint64* encoded_video_bytes_;
 163   uint64* encoded_audio_bytes_;
 164 };
 165
 166 struct MeasuringPoint {
 167   MeasuringPoint(double bitrate_, double latency_, double percent_packet_drop_)
 168       : bitrate(bitrate_),
 169         latency(latency_),
 170         percent_packet_drop(percent_packet_drop_) {}
 171   bool operator<=(const MeasuringPoint& other) const {
 172     return bitrate >= other.bitrate && latency <= other.latency &&
 173            percent_packet_drop <= other.percent_packet_drop;
 174   }
 175   bool operator>=(const MeasuringPoint& other) const {
 176     return bitrate <= other.bitrate && latency >= other.latency &&
 177            percent_packet_drop >= other.percent_packet_drop;
 178   }
 179
 180   std::string AsString() const {
 181     return base::StringPrintf(
 182         "%f Mbit/s %f ms %f %% ", bitrate, latency, percent_packet_drop);
 183   }
 184
 185   double bitrate;
 186   double latency;
 187   double percent_packet_drop;
 188 };
 189
 190 class RunOneBenchmark {
 191  public:
 192   RunOneBenchmark()
 193       : start_time_(),
 194         task_runner_(new test::FakeSingleThreadTaskRunner(&testing_clock_)),
 195         testing_clock_sender_(new test::SkewedTickClock(&testing_clock_)),
 196         task_runner_sender_(
 197             new test::SkewedSingleThreadTaskRunner(task_runner_)),
 198         testing_clock_receiver_(new test::SkewedTickClock(&testing_clock_)),
 199         task_runner_receiver_(
 200             new test::SkewedSingleThreadTaskRunner(task_runner_)),
 201         cast_environment_sender_(new CastEnvironment(
 202             scoped_ptr<base::TickClock>(testing_clock_sender_).Pass(),
 203             task_runner_sender_,
 204             task_runner_sender_,
 205             task_runner_sender_)),
 206         cast_environment_receiver_(new CastEnvironment(
 207             scoped_ptr<base::TickClock>(testing_clock_receiver_).Pass(),
 208             task_runner_receiver_,
 209             task_runner_receiver_,
 210             task_runner_receiver_)),
 211         receiver_to_sender_(cast_environment_receiver_),
 212         sender_to_receiver_(cast_environment_sender_),
 213         video_bytes_encoded_(0),
 214         audio_bytes_encoded_(0),
 215         frames_sent_(0) {
 216     testing_clock_.Advance(
 217         base::TimeDelta::FromMilliseconds(kStartMillisecond));
 218   }
 219
 220   void Configure(Codec video_codec,
 221                  Codec audio_codec,
 222                  int audio_sampling_frequency,
 223                  int max_number_of_video_buffers_used) {
 224     audio_sender_config_.ssrc = 1;
 225     audio_sender_config_.incoming_feedback_ssrc = 2;
 226     audio_sender_config_.target_playout_delay =
 227         base::TimeDelta::FromMilliseconds(kTargetPlayoutDelayMs);
 228     audio_sender_config_.rtp_payload_type = 96;
 229     audio_sender_config_.use_external_encoder = false;
 230     audio_sender_config_.frequency = audio_sampling_frequency;
 231     audio_sender_config_.channels = kAudioChannels;
 232     audio_sender_config_.bitrate = kDefaultAudioEncoderBitrate;
 233     audio_sender_config_.codec = audio_codec;
 234
 235     audio_receiver_config_.feedback_ssrc =
 236         audio_sender_config_.incoming_feedback_ssrc;
 237     audio_receiver_config_.incoming_ssrc = audio_sender_config_.ssrc;
 238     audio_receiver_config_.rtp_payload_type =
 239         audio_sender_config_.rtp_payload_type;
 240     audio_receiver_config_.frequency = audio_sender_config_.frequency;
 241     audio_receiver_config_.channels = kAudioChannels;
 242     audio_receiver_config_.max_frame_rate = 100;
 243     audio_receiver_config_.codec = audio_sender_config_.codec;
 244     audio_receiver_config_.rtp_max_delay_ms = kTargetPlayoutDelayMs;
 245
 246     video_sender_config_.ssrc = 3;
 247     video_sender_config_.incoming_feedback_ssrc = 4;
 248     video_sender_config_.target_playout_delay =
 249         base::TimeDelta::FromMilliseconds(kTargetPlayoutDelayMs);
 250     video_sender_config_.rtp_payload_type = 97;
 251     video_sender_config_.use_external_encoder = false;
 252     video_sender_config_.width = kVideoHdWidth;
 253     video_sender_config_.height = kVideoHdHeight;
 254 #if 0
 255     video_sender_config_.max_bitrate = 10000000;  // 10Mbit max
 256     video_sender_config_.min_bitrate = 1000000;   // 1Mbit min
 257     video_sender_config_.start_bitrate = 1000000; // 1Mbit start
 258 #else
 259     video_sender_config_.max_bitrate = 4000000;  // 4Mbit all the time
 260     video_sender_config_.min_bitrate = 4000000;
 261     video_sender_config_.start_bitrate = 4000000;
 262 #endif
 263     video_sender_config_.max_qp = 56;
 264     video_sender_config_.min_qp = 4;
 265     video_sender_config_.max_frame_rate = 30;
 266     video_sender_config_.max_number_of_video_buffers_used =
 267         max_number_of_video_buffers_used;
 268     video_sender_config_.codec = video_codec;
 269
 270     video_receiver_config_.feedback_ssrc =
 271         video_sender_config_.incoming_feedback_ssrc;
 272     video_receiver_config_.incoming_ssrc = video_sender_config_.ssrc;
 273     video_receiver_config_.rtp_payload_type =
 274         video_sender_config_.rtp_payload_type;
 275     video_receiver_config_.codec = video_sender_config_.codec;
 276     video_receiver_config_.frequency = kVideoFrequency;
 277     video_receiver_config_.channels = 1;
 278     video_receiver_config_.max_frame_rate = 100;
 279     video_receiver_config_.rtp_max_delay_ms = kTargetPlayoutDelayMs;
 280   }
 281
 282   void SetSenderClockSkew(double skew, base::TimeDelta offset) {
 283     testing_clock_sender_->SetSkew(skew, offset);
 284     task_runner_sender_->SetSkew(1.0 / skew);
 285   }
 286
 287   void SetReceiverClockSkew(double skew, base::TimeDelta offset) {
 288     testing_clock_receiver_->SetSkew(skew, offset);
 289     task_runner_receiver_->SetSkew(1.0 / skew);
 290   }
 291
 292   void Create(const MeasuringPoint& p) {
 293     cast_receiver_ = CastReceiver::Create(cast_environment_receiver_,
 294                                           audio_receiver_config_,
 295                                           video_receiver_config_,
 296                                           &receiver_to_sender_);
 297     net::IPEndPoint dummy_endpoint;
 298     transport_sender_.Init(
 299         new CastTransportSenderImpl(
 300             NULL,
 301             testing_clock_sender_,
 302             dummy_endpoint,
 303             base::Bind(&UpdateCastTransportStatus),
 304             base::Bind(&IgnoreRawEvents),
 305             base::TimeDelta::FromSeconds(1),
 306             task_runner_sender_,
 307             &sender_to_receiver_),
 308         &video_bytes_encoded_,
 309         &audio_bytes_encoded_);
 310
 311     cast_sender_ =
 312         CastSender::Create(cast_environment_sender_, &transport_sender_);
 313
 314     // Initializing audio and video senders.
 315     cast_sender_->InitializeAudio(audio_sender_config_,
 316                                   base::Bind(&AudioInitializationStatus));
 317     cast_sender_->InitializeVideo(video_sender_config_,
 318                                   base::Bind(&VideoInitializationStatus),
 319                                   CreateDefaultVideoEncodeAcceleratorCallback(),
 320                                   CreateDefaultVideoEncodeMemoryCallback());
 321
 322     receiver_to_sender_.Initialize(
 323         CreateSimplePipe(p).Pass(),
 324         transport_sender_.PacketReceiverForTesting(),
 325         task_runner_, &testing_clock_);
 326     sender_to_receiver_.Initialize(
 327         CreateSimplePipe(p).Pass(), cast_receiver_->packet_receiver(),
 328         task_runner_, &testing_clock_);
 329   }
 330
 331   virtual ~RunOneBenchmark() {
 332     cast_sender_.reset();
 333     cast_receiver_.reset();
 334     task_runner_->RunTasks();
 335   }
 336
 337   void SendFakeVideoFrame() {
 338     frames_sent_++;
 339     cast_sender_->video_frame_input()->InsertRawVideoFrame(
 340         media::VideoFrame::CreateBlackFrame(gfx::Size(2, 2)),
 341         testing_clock_sender_->NowTicks());
 342   }
 343
 344   void RunTasks(int ms) {
 345     task_runner_->Sleep(base::TimeDelta::FromMilliseconds(ms));
 346   }
 347
 348   void BasicPlayerGotVideoFrame(
 349       const scoped_refptr<media::VideoFrame>& video_frame,
 350       const base::TimeTicks& render_time,
 351       bool continuous) {
 352     video_ticks_.push_back(
 353         std::make_pair(testing_clock_receiver_->NowTicks(), render_time));
 354     cast_receiver_->RequestDecodedVideoFrame(base::Bind(
 355         &RunOneBenchmark::BasicPlayerGotVideoFrame, base::Unretained(this)));
 356   }
 357
 358   void BasicPlayerGotAudioFrame(scoped_ptr<AudioBus> audio_bus,
 359                                 const base::TimeTicks& playout_time,
 360                                 bool is_continuous) {
 361     audio_ticks_.push_back(
 362         std::make_pair(testing_clock_receiver_->NowTicks(), playout_time));
 363     cast_receiver_->RequestDecodedAudioFrame(base::Bind(
 364         &RunOneBenchmark::BasicPlayerGotAudioFrame, base::Unretained(this)));
 365   }
 366
 367   void StartBasicPlayer() {
 368     cast_receiver_->RequestDecodedVideoFrame(base::Bind(
 369         &RunOneBenchmark::BasicPlayerGotVideoFrame, base::Unretained(this)));
 370     cast_receiver_->RequestDecodedAudioFrame(base::Bind(
 371         &RunOneBenchmark::BasicPlayerGotAudioFrame, base::Unretained(this)));
 372   }
 373
 374   scoped_ptr<test::PacketPipe> CreateSimplePipe(const MeasuringPoint& p) {
 375     scoped_ptr<test::PacketPipe> pipe = test::NewBuffer(65536, p.bitrate);
 376     pipe->AppendToPipe(
 377         test::NewRandomDrop(p.percent_packet_drop / 100.0).Pass());
 378     pipe->AppendToPipe(test::NewConstantDelay(p.latency / 1000.0));
 379     return pipe.Pass();
 380   }
 381
 382   void Run(const MeasuringPoint& p) {
 383     available_bitrate_ = p.bitrate;
 384     Configure(
 385         CODEC_VIDEO_FAKE, CODEC_AUDIO_PCM16, 32000, 1);
 386     Create(p);
 387     StartBasicPlayer();
 388
 389     for (int frame = 0; frame < 1000; frame++) {
 390       SendFakeVideoFrame();
 391       RunTasks(kFrameTimerMs);
 392     }
 393     RunTasks(100 * kFrameTimerMs);  // Empty the pipeline.
 394     VLOG(1) << "=============INPUTS============";
 395     VLOG(1) << "Bitrate: " << p.bitrate << " mbit/s";
 396     VLOG(1) << "Latency: " << p.latency << " ms";
 397     VLOG(1) << "Packet drop drop: " << p.percent_packet_drop << "%";
 398     VLOG(1) << "=============OUTPUTS============";
 399     VLOG(1) << "Frames lost: " << frames_lost();
 400     VLOG(1) << "Late frames: " << late_frames();
 401     VLOG(1) << "Playout margin: " << frame_playout_buffer().AsString();
 402     VLOG(1) << "Video bandwidth used: " << video_bandwidth() << " mbit/s ("
 403             << (video_bandwidth() * 100 / desired_video_bitrate()) << "%)";
 404     VLOG(1) << "Good run: " << SimpleGood();
 405   }
 406
 407   // Metrics
 408   int frames_lost() const { return frames_sent_ - video_ticks_.size(); }
 409
 410   int late_frames() const {
 411     int frames = 0;
 412     // Ignore the first two seconds of video or so.
 413     for (size_t i = 60; i < video_ticks_.size(); i++) {
 414       if (video_ticks_[i].first > video_ticks_[i].second) {
 415         frames++;
 416       }
 417     }
 418     return frames;
 419   }
 420
 421   test::MeanAndError frame_playout_buffer() const {
 422     std::vector<double> values;
 423     for (size_t i = 0; i < video_ticks_.size(); i++) {
 424       values.push_back(
 425           (video_ticks_[i].second - video_ticks_[i].first).InMillisecondsF());
 426     }
 427     return test::MeanAndError(values);
 428   }
 429
 430   // Mbits per second
 431   double video_bandwidth() const {
 432     double seconds = (kFrameTimerMs * frames_sent_ / 1000.0);
 433     double megabits = video_bytes_encoded_ * 8 / 1000000.0;
 434     return megabits / seconds;
 435   }
 436
 437   // Mbits per second
 438   double audio_bandwidth() const {
 439     double seconds = (kFrameTimerMs * frames_sent_ / 1000.0);
 440     double megabits = audio_bytes_encoded_ * 8 / 1000000.0;
 441     return megabits / seconds;
 442   }
 443
 444   double desired_video_bitrate() {
 445     return std::min<double>(available_bitrate_,
 446                             video_sender_config_.max_bitrate / 1000000.0);
 447   }
 448
 449   bool SimpleGood() {
 450     return frames_lost() <= 1 && late_frames() <= 1 &&
 451            video_bandwidth() > desired_video_bitrate() * 0.8 &&
 452            video_bandwidth() < desired_video_bitrate() * 1.2;
 453   }
 454
 455  private:
 456   FrameReceiverConfig audio_receiver_config_;
 457   FrameReceiverConfig video_receiver_config_;
 458   AudioSenderConfig audio_sender_config_;
 459   VideoSenderConfig video_sender_config_;
 460
 461   base::TimeTicks start_time_;
 462
 463   // These run in "test time"
 464   base::SimpleTestTickClock testing_clock_;
 465   scoped_refptr<test::FakeSingleThreadTaskRunner> task_runner_;
 466
 467   // These run on the sender timeline.
 468   test::SkewedTickClock* testing_clock_sender_;
 469   scoped_refptr<test::SkewedSingleThreadTaskRunner> task_runner_sender_;
 470
 471   // These run on the receiver timeline.
 472   test::SkewedTickClock* testing_clock_receiver_;
 473   scoped_refptr<test::SkewedSingleThreadTaskRunner> task_runner_receiver_;
 474
 475   scoped_refptr<CastEnvironment> cast_environment_sender_;
 476   scoped_refptr<CastEnvironment> cast_environment_receiver_;
 477
 478   LoopBackTransport receiver_to_sender_;
 479   LoopBackTransport sender_to_receiver_;
 480   CastTransportSenderWrapper transport_sender_;
 481   uint64 video_bytes_encoded_;
 482   uint64 audio_bytes_encoded_;
 483
 484   scoped_ptr<CastReceiver> cast_receiver_;
 485   scoped_ptr<CastSender> cast_sender_;
 486
 487   int frames_sent_;
 488   double available_bitrate_;
 489   std::vector<std::pair<base::TimeTicks, base::TimeTicks> > audio_ticks_;
 490   std::vector<std::pair<base::TimeTicks, base::TimeTicks> > video_ticks_;
 491 };
 492
 493 enum CacheResult { FOUND_TRUE, FOUND_FALSE, NOT_FOUND };
 494
 495 template <class T>
 496 class BenchmarkCache {
 497  public:
 498   CacheResult Lookup(const T& x) {
 499     base::AutoLock key(lock_);
 500     for (size_t i = 0; i < results_.size(); i++) {
 501       if (results_[i].second) {
 502         if (x <= results_[i].first) {
 503           VLOG(2) << "TRUE because: " << x.AsString()
 504                   << " <= " << results_[i].first.AsString();
 505           return FOUND_TRUE;
 506         }
 507       } else {
 508         if (x >= results_[i].first) {
 509           VLOG(2) << "FALSE because: " << x.AsString()
 510                   << " >= " << results_[i].first.AsString();
 511           return FOUND_FALSE;
 512         }
 513       }
 514     }
 515     return NOT_FOUND;
 516   }
 517
 518   void Add(const T& x, bool result) {
 519     base::AutoLock key(lock_);
 520     VLOG(2) << "Cache Insert: " << x.AsString() << " = " << result;
 521     results_.push_back(std::make_pair(x, result));
 522   }
 523
 524  private:
 525   base::Lock lock_;
 526   std::vector<std::pair<T, bool> > results_;
 527 };
 528
 529 struct SearchVariable {
 530   SearchVariable() : base(0.0), grade(0.0) {}
 531   SearchVariable(double b, double g) : base(b), grade(g) {}
 532   SearchVariable blend(const SearchVariable& other, double factor) {
 533     CHECK_GE(factor, 0);
 534     CHECK_LE(factor, 1.0);
 535     return SearchVariable(base * (1 - factor) + other.base * factor,
 536                           grade * (1 - factor) + other.grade * factor);
 537   }
 538   double value(double x) const { return base + grade * x; }
 539   double base;
 540   double grade;
 541 };
 542
 543 struct SearchVector {
 544   SearchVector blend(const SearchVector& other, double factor) {
 545     SearchVector ret;
 546     ret.bitrate = bitrate.blend(other.bitrate, factor);
 547     ret.latency = latency.blend(other.latency, factor);
 548     ret.packet_drop = packet_drop.blend(other.packet_drop, factor);
 549     return ret;
 550   }
 551
 552   SearchVector average(const SearchVector& other) {
 553     return blend(other, 0.5);
 554   }
 555
 556   MeasuringPoint GetMeasuringPoint(double v) const {
 557     return MeasuringPoint(
 558         bitrate.value(-v), latency.value(v), packet_drop.value(v));
 559   }
 560   std::string AsString(double v) { return GetMeasuringPoint(v).AsString(); }
 561
 562   SearchVariable bitrate;
 563   SearchVariable latency;
 564   SearchVariable packet_drop;
 565 };
 566
 567 class CastBenchmark {
 568  public:
 569   bool RunOnePoint(const SearchVector& v, double multiplier) {
 570     MeasuringPoint p = v.GetMeasuringPoint(multiplier);
 571     VLOG(1) << "RUN: v = " << multiplier << " p = " << p.AsString();
 572     if (p.bitrate <= 0) {
 573       return false;
 574     }
 575     switch (cache_.Lookup(p)) {
 576       case FOUND_TRUE:
 577         return true;
 578       case FOUND_FALSE:
 579         return false;
 580       case NOT_FOUND:
 581         // Keep going
 582         break;
 583     }
 584     bool result = true;
 585     for (int tries = 0; tries < 3 && result; tries++) {
 586       RunOneBenchmark benchmark;
 587       benchmark.Run(p);
 588       result &= benchmark.SimpleGood();
 589     }
 590     cache_.Add(p, result);
 591     return result;
 592   }
 593
 594   void BinarySearch(SearchVector v, double accuracy) {
 595     double min = 0.0;
 596     double max = 1.0;
 597     while (RunOnePoint(v, max)) {
 598       min = max;
 599       max *= 2;
 600     }
 601
 602     while (max - min > accuracy) {
 603       double avg = (min + max) / 2;
 604       if (RunOnePoint(v, avg)) {
 605         min = avg;
 606       } else {
 607         max = avg;
 608       }
 609     }
 610
 611     // Print a data point to stdout.
 612     base::AutoLock key(lock_);
 613     MeasuringPoint p = v.GetMeasuringPoint(min);
 614     fprintf(stdout, "%f %f %f\n", p.bitrate, p.latency, p.percent_packet_drop);
 615     fflush(stdout);
 616   }
 617
 618   void SpanningSearch(int max,
 619                       int x,
 620                       int y,
 621                       int skip,
 622                       SearchVector a,
 623                       SearchVector b,
 624                       SearchVector c,
 625                       double accuracy,
 626                       std::vector<linked_ptr<base::Thread> >* threads) {
 627     static int thread_num = 0;
 628     if (x > max) return;
 629     if (skip > max) {
 630       if (y > x) return;
 631       SearchVector ab = a.blend(b, static_cast<double>(x) / max);
 632       SearchVector ac = a.blend(c, static_cast<double>(x) / max);
 633       SearchVector v = ab.blend(ac, x == y ? 1.0 : static_cast<double>(y) / x);
 634       thread_num++;
 635       (*threads)[thread_num % threads->size()]->message_loop()->PostTask(
 636           FROM_HERE,
 637           base::Bind(&CastBenchmark::BinarySearch,
 638                      base::Unretained(this),
 639                      v,
 640                      accuracy));
 641     } else {
 642       skip *= 2;
 643       SpanningSearch(max, x, y, skip, a, b, c, accuracy, threads);
 644       SpanningSearch(max, x + skip, y + skip, skip, a, b, c, accuracy, threads);
 645       SpanningSearch(max, x + skip, y, skip, a, b, c, accuracy, threads);
 646       SpanningSearch(max, x, y + skip, skip, a, b, c, accuracy, threads);
 647     }
 648   }
 649
 650   void Run() {
 651     // Spanning search.
 652
 653     std::vector<linked_ptr<base::Thread> > threads;
 654     for (int i = 0; i < 16; i++) {
 655       threads.push_back(make_linked_ptr(new base::Thread(
 656           base::StringPrintf("cast_bench_thread_%d", i))));
 657       threads[i]->Start();
 658     }
 659
 660     if (CommandLine::ForCurrentProcess()->HasSwitch("single-run")) {
 661       SearchVector a;
 662       a.bitrate.base = 100.0;
 663       a.bitrate.grade = 1.0;
 664       a.latency.grade = 1.0;
 665       a.packet_drop.grade = 1.0;
 666       threads[0]->message_loop()->PostTask(
 667           FROM_HERE,
 668           base::Bind(base::IgnoreResult(&CastBenchmark::RunOnePoint),
 669                      base::Unretained(this),
 670                      a,
 671                      1.0));
 672     } else {
 673       SearchVector a, b, c;
 674       a.bitrate.base = b.bitrate.base = c.bitrate.base = 100.0;
 675       a.bitrate.grade = 1.0;
 676       b.latency.grade = 1.0;
 677       c.packet_drop.grade = 1.0;
 678
 679       SpanningSearch(512,
 680                      0,
 681                      0,
 682                      1,
 683                      a,
 684                      b,
 685                      c,
 686                      0.01,
 687                      &threads);
 688     }
 689
 690     for (size_t i = 0; i < threads.size(); i++) {
 691       threads[i]->Stop();
 692     }
 693   }
 694
 695  private:
 696   BenchmarkCache<MeasuringPoint> cache_;
 697   base::Lock lock_;
 698 };
 699
 700 }  // namespace cast
 701 }  // namespace media
 702
 703 int main(int argc, char** argv) {
 704   base::AtExitManager at_exit;
 705   CommandLine::Init(argc, argv);
 706   media::cast::CastBenchmark benchmark;
 707   if (getenv("PROFILE_FILE")) {
 708     std::string profile_file(getenv("PROFILE_FILE"));
 709     base::debug::StartProfiling(profile_file);
 710     benchmark.Run();
 711     base::debug::StopProfiling();
 712   } else {
 713     benchmark.Run();
 714   }
 715 }