src/cc/scheduler/scheduler.cc

   1 // Copyright 2011 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 #include "cc/scheduler/scheduler.h"
   6
   7 #include <algorithm>
   8 #include "base/auto_reset.h"
   9 #include "base/debug/trace_event.h"
  10 #include "base/debug/trace_event_argument.h"
  11 #include "base/logging.h"
  12 #include "base/single_thread_task_runner.h"
  13 #include "cc/debug/devtools_instrumentation.h"
  14 #include "cc/debug/traced_value.h"
  15 #include "cc/scheduler/delay_based_time_source.h"
  16 #include "ui/gfx/frame_time.h"
  17
  18 namespace cc {
  19
  20 BeginFrameSource* SchedulerFrameSourcesConstructor::ConstructPrimaryFrameSource(
  21     Scheduler* scheduler) {
  22   if (!scheduler->settings_.throttle_frame_production) {
  23     TRACE_EVENT1("cc",
  24                  "Scheduler::Scheduler()",
  25                  "PrimaryFrameSource",
  26                  "BackToBackBeginFrameSource");
  27     DCHECK(!scheduler->primary_frame_source_internal_);
  28     scheduler->primary_frame_source_internal_ =
  29         BackToBackBeginFrameSource::Create(scheduler->task_runner_.get());
  30     return scheduler->primary_frame_source_internal_.get();
  31   } else if (scheduler->settings_.begin_frame_scheduling_enabled) {
  32     TRACE_EVENT1("cc",
  33                  "Scheduler::Scheduler()",
  34                  "PrimaryFrameSource",
  35                  "SchedulerClient");
  36     return scheduler->client_->ExternalBeginFrameSource();
  37   } else {
  38     TRACE_EVENT1("cc",
  39                  "Scheduler::Scheduler()",
  40                  "PrimaryFrameSource",
  41                  "SyntheticBeginFrameSource");
  42     scoped_ptr<SyntheticBeginFrameSource> synthetic_source =
  43         SyntheticBeginFrameSource::Create(scheduler->task_runner_.get(),
  44                                           scheduler->Now(),
  45                                           BeginFrameArgs::DefaultInterval());
  46
  47     DCHECK(!scheduler->vsync_observer_);
  48     scheduler->vsync_observer_ = synthetic_source.get();
  49
  50     DCHECK(!scheduler->primary_frame_source_internal_);
  51     scheduler->primary_frame_source_internal_ = synthetic_source.Pass();
  52     return scheduler->primary_frame_source_internal_.get();
  53   }
  54 }
  55
  56 BeginFrameSource*
  57 SchedulerFrameSourcesConstructor::ConstructBackgroundFrameSource(
  58     Scheduler* scheduler) {
  59   TRACE_EVENT1("cc",
  60                "Scheduler::Scheduler()",
  61                "BackgroundFrameSource",
  62                "SyntheticBeginFrameSource");
  63   DCHECK(!(scheduler->background_frame_source_internal_));
  64   scheduler->background_frame_source_internal_ =
  65       SyntheticBeginFrameSource::Create(scheduler->task_runner_.get(),
  66                                         scheduler->Now(),
  67                                         base::TimeDelta::FromSeconds(1));
  68   return scheduler->background_frame_source_internal_.get();
  69 }
  70
  71 Scheduler::Scheduler(
  72     SchedulerClient* client,
  73     const SchedulerSettings& scheduler_settings,
  74     int layer_tree_host_id,
  75     const scoped_refptr<base::SingleThreadTaskRunner>& task_runner,
  76     base::PowerMonitor* power_monitor,
  77     SchedulerFrameSourcesConstructor* frame_sources_constructor)
  78     : frame_source_(),
  79       primary_frame_source_(NULL),
  80       background_frame_source_(NULL),
  81       primary_frame_source_internal_(),
  82       background_frame_source_internal_(),
  83       vsync_observer_(NULL),
  84       settings_(scheduler_settings),
  85       client_(client),
  86       layer_tree_host_id_(layer_tree_host_id),
  87       task_runner_(task_runner),
  88       power_monitor_(power_monitor),
  89       begin_retro_frame_posted_(false),
  90       state_machine_(scheduler_settings),
  91       inside_process_scheduled_actions_(false),
  92       inside_action_(SchedulerStateMachine::ACTION_NONE),
  93       weak_factory_(this) {
  94   TRACE_EVENT1(TRACE_DISABLED_BY_DEFAULT("cc.debug.scheduler"),
  95                "Scheduler::Scheduler",
  96                "settings",
  97                settings_.AsValue());
  98   DCHECK(client_);
  99   DCHECK(!state_machine_.BeginFrameNeeded());
 100
 101   begin_retro_frame_closure_ =
 102       base::Bind(&Scheduler::BeginRetroFrame, weak_factory_.GetWeakPtr());
 103   begin_impl_frame_deadline_closure_ = base::Bind(
 104       &Scheduler::OnBeginImplFrameDeadline, weak_factory_.GetWeakPtr());
 105   poll_for_draw_triggers_closure_ = base::Bind(
 106       &Scheduler::PollForAnticipatedDrawTriggers, weak_factory_.GetWeakPtr());
 107   advance_commit_state_closure_ = base::Bind(
 108       &Scheduler::PollToAdvanceCommitState, weak_factory_.GetWeakPtr());
 109
 110   frame_source_ = BeginFrameSourceMultiplexer::Create();
 111   frame_source_->AddObserver(this);
 112
 113   // Primary frame source
 114   primary_frame_source_ =
 115       frame_sources_constructor->ConstructPrimaryFrameSource(this);
 116   frame_source_->AddSource(primary_frame_source_);
 117
 118   // Background ticking frame source
 119   background_frame_source_ =
 120       frame_sources_constructor->ConstructBackgroundFrameSource(this);
 121   frame_source_->AddSource(background_frame_source_);
 122
 123   SetupPowerMonitoring();
 124 }
 125
 126 Scheduler::~Scheduler() {
 127   TeardownPowerMonitoring();
 128 }
 129
 130 base::TimeTicks Scheduler::Now() const {
 131   base::TimeTicks now = gfx::FrameTime::Now();
 132   TRACE_EVENT1(TRACE_DISABLED_BY_DEFAULT("cc.debug.scheduler.now"),
 133                "Scheduler::Now",
 134                "now",
 135                now);
 136   return now;
 137 }
 138
 139 void Scheduler::SetupPowerMonitoring() {
 140   if (settings_.disable_hi_res_timer_tasks_on_battery) {
 141     DCHECK(power_monitor_);
 142     power_monitor_->AddObserver(this);
 143     state_machine_.SetImplLatencyTakesPriorityOnBattery(
 144         power_monitor_->IsOnBatteryPower());
 145   }
 146 }
 147
 148 void Scheduler::TeardownPowerMonitoring() {
 149   if (settings_.disable_hi_res_timer_tasks_on_battery) {
 150     DCHECK(power_monitor_);
 151     power_monitor_->RemoveObserver(this);
 152   }
 153 }
 154
 155 void Scheduler::OnPowerStateChange(bool on_battery_power) {
 156   DCHECK(settings_.disable_hi_res_timer_tasks_on_battery);
 157   state_machine_.SetImplLatencyTakesPriorityOnBattery(on_battery_power);
 158 }
 159
 160 void Scheduler::CommitVSyncParameters(base::TimeTicks timebase,
 161                                       base::TimeDelta interval) {
 162   // TODO(brianderson): We should not be receiving 0 intervals.
 163   if (interval == base::TimeDelta())
 164     interval = BeginFrameArgs::DefaultInterval();
 165
 166   if (vsync_observer_)
 167     vsync_observer_->OnUpdateVSyncParameters(timebase, interval);
 168 }
 169
 170 void Scheduler::SetEstimatedParentDrawTime(base::TimeDelta draw_time) {
 171   DCHECK_GE(draw_time.ToInternalValue(), 0);
 172   estimated_parent_draw_time_ = draw_time;
 173 }
 174
 175 void Scheduler::SetCanStart() {
 176   state_machine_.SetCanStart();
 177   ProcessScheduledActions();
 178 }
 179
 180 void Scheduler::SetVisible(bool visible) {
 181   state_machine_.SetVisible(visible);
 182   if (visible) {
 183     frame_source_->SetActiveSource(primary_frame_source_);
 184   } else {
 185     frame_source_->SetActiveSource(background_frame_source_);
 186   }
 187   ProcessScheduledActions();
 188 }
 189
 190 void Scheduler::SetCanDraw(bool can_draw) {
 191   state_machine_.SetCanDraw(can_draw);
 192   ProcessScheduledActions();
 193 }
 194
 195 void Scheduler::NotifyReadyToActivate() {
 196   state_machine_.NotifyReadyToActivate();
 197   ProcessScheduledActions();
 198 }
 199
 200 void Scheduler::SetNeedsCommit() {
 201   state_machine_.SetNeedsCommit();
 202   ProcessScheduledActions();
 203 }
 204
 205 void Scheduler::SetNeedsRedraw() {
 206   state_machine_.SetNeedsRedraw();
 207   ProcessScheduledActions();
 208 }
 209
 210 void Scheduler::SetNeedsAnimate() {
 211   state_machine_.SetNeedsAnimate();
 212   ProcessScheduledActions();
 213 }
 214
 215 void Scheduler::SetNeedsManageTiles() {
 216   DCHECK(!IsInsideAction(SchedulerStateMachine::ACTION_MANAGE_TILES));
 217   state_machine_.SetNeedsManageTiles();
 218   ProcessScheduledActions();
 219 }
 220
 221 void Scheduler::SetMaxSwapsPending(int max) {
 222   state_machine_.SetMaxSwapsPending(max);
 223 }
 224
 225 void Scheduler::DidSwapBuffers() {
 226   state_machine_.DidSwapBuffers();
 227
 228   // There is no need to call ProcessScheduledActions here because
 229   // swapping should not trigger any new actions.
 230   if (!inside_process_scheduled_actions_) {
 231     DCHECK_EQ(state_machine_.NextAction(), SchedulerStateMachine::ACTION_NONE);
 232   }
 233 }
 234
 235 void Scheduler::SetSwapUsedIncompleteTile(bool used_incomplete_tile) {
 236   state_machine_.SetSwapUsedIncompleteTile(used_incomplete_tile);
 237   ProcessScheduledActions();
 238 }
 239
 240 void Scheduler::DidSwapBuffersComplete() {
 241   state_machine_.DidSwapBuffersComplete();
 242   ProcessScheduledActions();
 243 }
 244
 245 void Scheduler::SetImplLatencyTakesPriority(bool impl_latency_takes_priority) {
 246   state_machine_.SetImplLatencyTakesPriority(impl_latency_takes_priority);
 247   ProcessScheduledActions();
 248 }
 249
 250 void Scheduler::NotifyReadyToCommit() {
 251   TRACE_EVENT0("cc", "Scheduler::NotifyReadyToCommit");
 252   state_machine_.NotifyReadyToCommit();
 253   ProcessScheduledActions();
 254 }
 255
 256 void Scheduler::BeginMainFrameAborted(bool did_handle) {
 257   TRACE_EVENT0("cc", "Scheduler::BeginMainFrameAborted");
 258   state_machine_.BeginMainFrameAborted(did_handle);
 259   ProcessScheduledActions();
 260 }
 261
 262 void Scheduler::DidManageTiles() {
 263   state_machine_.DidManageTiles();
 264 }
 265
 266 void Scheduler::DidLoseOutputSurface() {
 267   TRACE_EVENT0("cc", "Scheduler::DidLoseOutputSurface");
 268   state_machine_.DidLoseOutputSurface();
 269   if (frame_source_->NeedsBeginFrames())
 270     frame_source_->SetNeedsBeginFrames(false);
 271   begin_retro_frame_args_.clear();
 272   ProcessScheduledActions();
 273 }
 274
 275 void Scheduler::DidCreateAndInitializeOutputSurface() {
 276   TRACE_EVENT0("cc", "Scheduler::DidCreateAndInitializeOutputSurface");
 277   DCHECK(!frame_source_->NeedsBeginFrames());
 278   DCHECK(begin_impl_frame_deadline_task_.IsCancelled());
 279   state_machine_.DidCreateAndInitializeOutputSurface();
 280   ProcessScheduledActions();
 281 }
 282
 283 void Scheduler::NotifyBeginMainFrameStarted() {
 284   TRACE_EVENT0("cc", "Scheduler::NotifyBeginMainFrameStarted");
 285   state_machine_.NotifyBeginMainFrameStarted();
 286 }
 287
 288 base::TimeTicks Scheduler::AnticipatedDrawTime() const {
 289   if (!frame_source_->NeedsBeginFrames() ||
 290       begin_impl_frame_args_.interval <= base::TimeDelta())
 291     return base::TimeTicks();
 292
 293   base::TimeTicks now = Now();
 294   base::TimeTicks timebase = std::max(begin_impl_frame_args_.frame_time,
 295                                       begin_impl_frame_args_.deadline);
 296   int64 intervals = 1 + ((now - timebase) / begin_impl_frame_args_.interval);
 297   return timebase + (begin_impl_frame_args_.interval * intervals);
 298 }
 299
 300 base::TimeTicks Scheduler::LastBeginImplFrameTime() {
 301   return begin_impl_frame_args_.frame_time;
 302 }
 303
 304 void Scheduler::SetupNextBeginFrameIfNeeded() {
 305   if (!task_runner_.get())
 306     return;
 307
 308   bool needs_begin_frame = state_machine_.BeginFrameNeeded();
 309
 310   bool at_end_of_deadline =
 311       (state_machine_.begin_impl_frame_state() ==
 312        SchedulerStateMachine::BEGIN_IMPL_FRAME_STATE_INSIDE_DEADLINE);
 313
 314   bool should_call_set_needs_begin_frame =
 315       // Always request the BeginFrame immediately if it wasn't needed before.
 316       (needs_begin_frame && !frame_source_->NeedsBeginFrames()) ||
 317       // Only stop requesting BeginFrames after a deadline.
 318       (!needs_begin_frame && frame_source_->NeedsBeginFrames() &&
 319        at_end_of_deadline);
 320
 321   if (should_call_set_needs_begin_frame) {
 322     frame_source_->SetNeedsBeginFrames(needs_begin_frame);
 323   }
 324
 325   if (at_end_of_deadline) {
 326     frame_source_->DidFinishFrame(begin_retro_frame_args_.size());
 327   }
 328
 329   PostBeginRetroFrameIfNeeded();
 330   SetupPollingMechanisms(needs_begin_frame);
 331 }
 332
 333 // We may need to poll when we can't rely on BeginFrame to advance certain
 334 // state or to avoid deadlock.
 335 void Scheduler::SetupPollingMechanisms(bool needs_begin_frame) {
 336   bool needs_advance_commit_state_timer = false;
 337   // Setup PollForAnticipatedDrawTriggers if we need to monitor state but
 338   // aren't expecting any more BeginFrames. This should only be needed by
 339   // the synchronous compositor when BeginFrameNeeded is false.
 340   if (state_machine_.ShouldPollForAnticipatedDrawTriggers()) {
 341     DCHECK(!state_machine_.SupportsProactiveBeginFrame());
 342     DCHECK(!needs_begin_frame);
 343     if (poll_for_draw_triggers_task_.IsCancelled()) {
 344       poll_for_draw_triggers_task_.Reset(poll_for_draw_triggers_closure_);
 345       base::TimeDelta delay = begin_impl_frame_args_.IsValid()
 346                                   ? begin_impl_frame_args_.interval
 347                                   : BeginFrameArgs::DefaultInterval();
 348       task_runner_->PostDelayedTask(
 349           FROM_HERE, poll_for_draw_triggers_task_.callback(), delay);
 350     }
 351   } else {
 352     poll_for_draw_triggers_task_.Cancel();
 353
 354     // At this point we'd prefer to advance through the commit flow by
 355     // drawing a frame, however it's possible that the frame rate controller
 356     // will not give us a BeginFrame until the commit completes.  See
 357     // crbug.com/317430 for an example of a swap ack being held on commit. Thus
 358     // we set a repeating timer to poll on ProcessScheduledActions until we
 359     // successfully reach BeginFrame. Synchronous compositor does not use
 360     // frame rate controller or have the circular wait in the bug.
 361     if (IsBeginMainFrameSentOrStarted() &&
 362         !settings_.using_synchronous_renderer_compositor) {
 363       needs_advance_commit_state_timer = true;
 364     }
 365   }
 366
 367   if (needs_advance_commit_state_timer) {
 368     if (advance_commit_state_task_.IsCancelled() &&
 369         begin_impl_frame_args_.IsValid()) {
 370       // Since we'd rather get a BeginImplFrame by the normal mechanism, we
 371       // set the interval to twice the interval from the previous frame.
 372       advance_commit_state_task_.Reset(advance_commit_state_closure_);
 373       task_runner_->PostDelayedTask(FROM_HERE,
 374                                     advance_commit_state_task_.callback(),
 375                                     begin_impl_frame_args_.interval * 2);
 376     }
 377   } else {
 378     advance_commit_state_task_.Cancel();
 379   }
 380 }
 381
 382 // BeginFrame is the mechanism that tells us that now is a good time to start
 383 // making a frame. Usually this means that user input for the frame is complete.
 384 // If the scheduler is busy, we queue the BeginFrame to be handled later as
 385 // a BeginRetroFrame.
 386 bool Scheduler::OnBeginFrameMixInDelegate(const BeginFrameArgs& args) {
 387   TRACE_EVENT1("cc", "Scheduler::BeginFrame", "args", args.AsValue());
 388
 389   // We have just called SetNeedsBeginFrame(true) and the BeginFrameSource has
 390   // sent us the last BeginFrame we have missed. As we might not be able to
 391   // actually make rendering for this call, handle it like a "retro frame".
 392   // TODO(brainderson): Add a test for this functionality ASAP!
 393   if (args.type == BeginFrameArgs::MISSED) {
 394     begin_retro_frame_args_.push_back(args);
 395     PostBeginRetroFrameIfNeeded();
 396     return true;
 397   }
 398
 399   BeginFrameArgs adjusted_args(args);
 400   adjusted_args.deadline -= EstimatedParentDrawTime();
 401
 402   bool should_defer_begin_frame;
 403   if (settings_.using_synchronous_renderer_compositor) {
 404     should_defer_begin_frame = false;
 405   } else {
 406     should_defer_begin_frame =
 407         !begin_retro_frame_args_.empty() || begin_retro_frame_posted_ ||
 408         !frame_source_->NeedsBeginFrames() ||
 409         (state_machine_.begin_impl_frame_state() !=
 410          SchedulerStateMachine::BEGIN_IMPL_FRAME_STATE_IDLE);
 411   }
 412
 413   if (should_defer_begin_frame) {
 414     begin_retro_frame_args_.push_back(adjusted_args);
 415     TRACE_EVENT_INSTANT0(
 416         "cc", "Scheduler::BeginFrame deferred", TRACE_EVENT_SCOPE_THREAD);
 417     // Queuing the frame counts as "using it", so we need to return true.
 418   } else {
 419     BeginImplFrame(adjusted_args);
 420   }
 421   return true;
 422 }
 423
 424 // BeginRetroFrame is called for BeginFrames that we've deferred because
 425 // the scheduler was in the middle of processing a previous BeginFrame.
 426 void Scheduler::BeginRetroFrame() {
 427   TRACE_EVENT0("cc", "Scheduler::BeginRetroFrame");
 428   DCHECK(!settings_.using_synchronous_renderer_compositor);
 429   DCHECK(begin_retro_frame_posted_);
 430   begin_retro_frame_posted_ = false;
 431
 432   // If there aren't any retroactive BeginFrames, then we've lost the
 433   // OutputSurface and should abort.
 434   if (begin_retro_frame_args_.empty())
 435     return;
 436
 437   // Discard expired BeginRetroFrames
 438   // Today, we should always end up with at most one un-expired BeginRetroFrame
 439   // because deadlines will not be greater than the next frame time. We don't
 440   // DCHECK though because some systems don't always have monotonic timestamps.
 441   // TODO(brianderson): In the future, long deadlines could result in us not
 442   // draining the queue if we don't catch up. If we consistently can't catch
 443   // up, our fallback should be to lower our frame rate.
 444   base::TimeTicks now = Now();
 445   base::TimeDelta draw_duration_estimate = client_->DrawDurationEstimate();
 446   while (!begin_retro_frame_args_.empty()) {
 447     base::TimeTicks adjusted_deadline = AdjustedBeginImplFrameDeadline(
 448         begin_retro_frame_args_.front(), draw_duration_estimate);
 449     if (now <= adjusted_deadline)
 450       break;
 451
 452     TRACE_EVENT_INSTANT2("cc",
 453                          "Scheduler::BeginRetroFrame discarding",
 454                          TRACE_EVENT_SCOPE_THREAD,
 455                          "deadline - now",
 456                          (adjusted_deadline - now).InMicroseconds(),
 457                          "BeginFrameArgs",
 458                          begin_retro_frame_args_.front().AsValue());
 459     begin_retro_frame_args_.pop_front();
 460     frame_source_->DidFinishFrame(begin_retro_frame_args_.size());
 461   }
 462
 463   if (begin_retro_frame_args_.empty()) {
 464     TRACE_EVENT_INSTANT0("cc",
 465                          "Scheduler::BeginRetroFrames all expired",
 466                          TRACE_EVENT_SCOPE_THREAD);
 467   } else {
 468     BeginImplFrame(begin_retro_frame_args_.front());
 469     begin_retro_frame_args_.pop_front();
 470   }
 471 }
 472
 473 // There could be a race between the posted BeginRetroFrame and a new
 474 // BeginFrame arriving via the normal mechanism. Scheduler::BeginFrame
 475 // will check if there is a pending BeginRetroFrame to ensure we handle
 476 // BeginFrames in FIFO order.
 477 void Scheduler::PostBeginRetroFrameIfNeeded() {
 478   TRACE_EVENT1(TRACE_DISABLED_BY_DEFAULT("cc.debug.scheduler"),
 479                "Scheduler::PostBeginRetroFrameIfNeeded",
 480                "state",
 481                AsValue());
 482   if (!frame_source_->NeedsBeginFrames())
 483     return;
 484
 485   if (begin_retro_frame_args_.empty() || begin_retro_frame_posted_)
 486     return;
 487
 488   // begin_retro_frame_args_ should always be empty for the
 489   // synchronous compositor.
 490   DCHECK(!settings_.using_synchronous_renderer_compositor);
 491
 492   if (state_machine_.begin_impl_frame_state() !=
 493       SchedulerStateMachine::BEGIN_IMPL_FRAME_STATE_IDLE)
 494     return;
 495
 496   begin_retro_frame_posted_ = true;
 497   task_runner_->PostTask(FROM_HERE, begin_retro_frame_closure_);
 498 }
 499
 500 // BeginImplFrame starts a compositor frame that will wait up until a deadline
 501 // for a BeginMainFrame+activation to complete before it times out and draws
 502 // any asynchronous animation and scroll/pinch updates.
 503 void Scheduler::BeginImplFrame(const BeginFrameArgs& args) {
 504   bool main_thread_is_in_high_latency_mode =
 505       state_machine_.MainThreadIsInHighLatencyMode();
 506   TRACE_EVENT2("cc",
 507                "Scheduler::BeginImplFrame",
 508                "args",
 509                args.AsValue(),
 510                "main_thread_is_high_latency",
 511                main_thread_is_in_high_latency_mode);
 512   TRACE_COUNTER1(TRACE_DISABLED_BY_DEFAULT("cc.debug.scheduler"),
 513                  "MainThreadLatency",
 514                  main_thread_is_in_high_latency_mode);
 515   DCHECK_EQ(state_machine_.begin_impl_frame_state(),
 516             SchedulerStateMachine::BEGIN_IMPL_FRAME_STATE_IDLE);
 517   DCHECK(state_machine_.HasInitializedOutputSurface());
 518
 519   advance_commit_state_task_.Cancel();
 520
 521   base::TimeDelta draw_duration_estimate = client_->DrawDurationEstimate();
 522   begin_impl_frame_args_ = args;
 523   begin_impl_frame_args_.deadline -= draw_duration_estimate;
 524
 525   if (!state_machine_.impl_latency_takes_priority() &&
 526       main_thread_is_in_high_latency_mode &&
 527       CanCommitAndActivateBeforeDeadline()) {
 528     state_machine_.SetSkipNextBeginMainFrameToReduceLatency();
 529   }
 530
 531   client_->WillBeginImplFrame(begin_impl_frame_args_);
 532   state_machine_.OnBeginImplFrame(begin_impl_frame_args_);
 533   devtools_instrumentation::DidBeginFrame(layer_tree_host_id_);
 534
 535   ProcessScheduledActions();
 536
 537   state_machine_.OnBeginImplFrameDeadlinePending();
 538   ScheduleBeginImplFrameDeadline(
 539       AdjustedBeginImplFrameDeadline(args, draw_duration_estimate));
 540 }
 541
 542 base::TimeTicks Scheduler::AdjustedBeginImplFrameDeadline(
 543     const BeginFrameArgs& args,
 544     base::TimeDelta draw_duration_estimate) const {
 545   if (settings_.using_synchronous_renderer_compositor) {
 546     // The synchronous compositor needs to draw right away.
 547     return base::TimeTicks();
 548   } else if (state_machine_.ShouldTriggerBeginImplFrameDeadlineEarly()) {
 549     // We are ready to draw a new active tree immediately.
 550     return base::TimeTicks();
 551   } else if (state_machine_.needs_redraw()) {
 552     // We have an animation or fast input path on the impl thread that wants
 553     // to draw, so don't wait too long for a new active tree.
 554     return args.deadline - draw_duration_estimate;
 555   } else {
 556     // The impl thread doesn't have anything it wants to draw and we are just
 557     // waiting for a new active tree, so post the deadline for the next
 558     // expected BeginImplFrame start. This allows us to draw immediately when
 559     // there is a new active tree, instead of waiting for the next
 560     // BeginImplFrame.
 561     // TODO(brianderson): Handle long deadlines (that are past the next frame's
 562     // frame time) properly instead of using this hack.
 563     return args.frame_time + args.interval;
 564   }
 565 }
 566
 567 void Scheduler::ScheduleBeginImplFrameDeadline(base::TimeTicks deadline) {
 568   TRACE_EVENT1(
 569       "cc", "Scheduler::ScheduleBeginImplFrameDeadline", "deadline", deadline);
 570   if (settings_.using_synchronous_renderer_compositor) {
 571     // The synchronous renderer compositor has to make its GL calls
 572     // within this call.
 573     // TODO(brianderson): Have the OutputSurface initiate the deadline tasks
 574     // so the sychronous renderer compositor can take advantage of splitting
 575     // up the BeginImplFrame and deadline as well.
 576     OnBeginImplFrameDeadline();
 577     return;
 578   }
 579   begin_impl_frame_deadline_task_.Cancel();
 580   begin_impl_frame_deadline_task_.Reset(begin_impl_frame_deadline_closure_);
 581
 582   base::TimeDelta delta = deadline - Now();
 583   if (delta <= base::TimeDelta())
 584     delta = base::TimeDelta();
 585   task_runner_->PostDelayedTask(
 586       FROM_HERE, begin_impl_frame_deadline_task_.callback(), delta);
 587 }
 588
 589 void Scheduler::OnBeginImplFrameDeadline() {
 590   TRACE_EVENT0("cc", "Scheduler::OnBeginImplFrameDeadline");
 591   begin_impl_frame_deadline_task_.Cancel();
 592
 593   // We split the deadline actions up into two phases so the state machine
 594   // has a chance to trigger actions that should occur durring and after
 595   // the deadline separately. For example:
 596   // * Sending the BeginMainFrame will not occur after the deadline in
 597   //     order to wait for more user-input before starting the next commit.
 598   // * Creating a new OuputSurface will not occur during the deadline in
 599   //     order to allow the state machine to "settle" first.
 600   state_machine_.OnBeginImplFrameDeadline();
 601   ProcessScheduledActions();
 602   state_machine_.OnBeginImplFrameIdle();
 603   ProcessScheduledActions();
 604
 605   client_->DidBeginImplFrameDeadline();
 606 }
 607
 608 void Scheduler::PollForAnticipatedDrawTriggers() {
 609   TRACE_EVENT0("cc", "Scheduler::PollForAnticipatedDrawTriggers");
 610   poll_for_draw_triggers_task_.Cancel();
 611   state_machine_.DidEnterPollForAnticipatedDrawTriggers();
 612   ProcessScheduledActions();
 613   state_machine_.DidLeavePollForAnticipatedDrawTriggers();
 614 }
 615
 616 void Scheduler::PollToAdvanceCommitState() {
 617   TRACE_EVENT0("cc", "Scheduler::PollToAdvanceCommitState");
 618   advance_commit_state_task_.Cancel();
 619   ProcessScheduledActions();
 620 }
 621
 622 void Scheduler::DrawAndSwapIfPossible() {
 623   DrawResult result = client_->ScheduledActionDrawAndSwapIfPossible();
 624   state_machine_.DidDrawIfPossibleCompleted(result);
 625 }
 626
 627 void Scheduler::ProcessScheduledActions() {
 628   // We do not allow ProcessScheduledActions to be recursive.
 629   // The top-level call will iteratively execute the next action for us anyway.
 630   if (inside_process_scheduled_actions_)
 631     return;
 632
 633   base::AutoReset<bool> mark_inside(&inside_process_scheduled_actions_, true);
 634
 635   SchedulerStateMachine::Action action;
 636   do {
 637     action = state_machine_.NextAction();
 638     TRACE_EVENT1(TRACE_DISABLED_BY_DEFAULT("cc.debug.scheduler"),
 639                  "SchedulerStateMachine",
 640                  "state",
 641                  AsValue());
 642     VLOG(2) << "Scheduler::ProcessScheduledActions: "
 643             << SchedulerStateMachine::ActionToString(action) << " "
 644             << state_machine_.GetStatesForDebugging();
 645     state_machine_.UpdateState(action);
 646     base::AutoReset<SchedulerStateMachine::Action>
 647         mark_inside_action(&inside_action_, action);
 648     switch (action) {
 649       case SchedulerStateMachine::ACTION_NONE:
 650         break;
 651       case SchedulerStateMachine::ACTION_ANIMATE:
 652         client_->ScheduledActionAnimate();
 653         break;
 654       case SchedulerStateMachine::ACTION_SEND_BEGIN_MAIN_FRAME:
 655         client_->ScheduledActionSendBeginMainFrame();
 656         break;
 657       case SchedulerStateMachine::ACTION_COMMIT:
 658         client_->ScheduledActionCommit();
 659         break;
 660       case SchedulerStateMachine::ACTION_UPDATE_VISIBLE_TILES:
 661         client_->ScheduledActionUpdateVisibleTiles();
 662         break;
 663       case SchedulerStateMachine::ACTION_ACTIVATE_SYNC_TREE:
 664         client_->ScheduledActionActivateSyncTree();
 665         break;
 666       case SchedulerStateMachine::ACTION_DRAW_AND_SWAP_IF_POSSIBLE:
 667         DrawAndSwapIfPossible();
 668         break;
 669       case SchedulerStateMachine::ACTION_DRAW_AND_SWAP_FORCED:
 670         client_->ScheduledActionDrawAndSwapForced();
 671         break;
 672       case SchedulerStateMachine::ACTION_DRAW_AND_SWAP_ABORT:
 673         // No action is actually performed, but this allows the state machine to
 674         // advance out of its waiting to draw state without actually drawing.
 675         break;
 676       case SchedulerStateMachine::ACTION_BEGIN_OUTPUT_SURFACE_CREATION:
 677         client_->ScheduledActionBeginOutputSurfaceCreation();
 678         break;
 679       case SchedulerStateMachine::ACTION_MANAGE_TILES:
 680         client_->ScheduledActionManageTiles();
 681         break;
 682     }
 683   } while (action != SchedulerStateMachine::ACTION_NONE);
 684
 685   SetupNextBeginFrameIfNeeded();
 686   client_->DidAnticipatedDrawTimeChange(AnticipatedDrawTime());
 687
 688   if (state_machine_.ShouldTriggerBeginImplFrameDeadlineEarly()) {
 689     DCHECK(!settings_.using_synchronous_renderer_compositor);
 690     ScheduleBeginImplFrameDeadline(base::TimeTicks());
 691   }
 692 }
 693
 694 bool Scheduler::WillDrawIfNeeded() const {
 695   return !state_machine_.PendingDrawsShouldBeAborted();
 696 }
 697
 698 scoped_refptr<base::debug::ConvertableToTraceFormat> Scheduler::AsValue()
 699     const {
 700   scoped_refptr<base::debug::TracedValue> state =
 701       new base::debug::TracedValue();
 702   AsValueInto(state.get());
 703   return state;
 704 }
 705
 706 void Scheduler::AsValueInto(base::debug::TracedValue* state) const {
 707   state->BeginDictionary("state_machine");
 708   state_machine_.AsValueInto(state, Now());
 709   state->EndDictionary();
 710
 711   // Only trace frame sources when explicitly enabled - http://crbug.com/420607
 712   bool frame_tracing_enabled = false;
 713   TRACE_EVENT_CATEGORY_GROUP_ENABLED(
 714       TRACE_DISABLED_BY_DEFAULT("cc.debug.scheduler.frames"),
 715       &frame_tracing_enabled);
 716   if (frame_tracing_enabled) {
 717     state->BeginDictionary("frame_source_");
 718     frame_source_->AsValueInto(state);
 719     state->EndDictionary();
 720   }
 721
 722   state->BeginDictionary("scheduler_state");
 723   state->SetDouble("time_until_anticipated_draw_time_ms",
 724                    (AnticipatedDrawTime() - Now()).InMillisecondsF());
 725   state->SetDouble("estimated_parent_draw_time_ms",
 726                    estimated_parent_draw_time_.InMillisecondsF());
 727   state->SetBoolean("last_set_needs_begin_frame_",
 728                     frame_source_->NeedsBeginFrames());
 729   state->SetBoolean("begin_retro_frame_posted_", begin_retro_frame_posted_);
 730   state->SetInteger("begin_retro_frame_args_", begin_retro_frame_args_.size());
 731   state->SetBoolean("begin_impl_frame_deadline_task_",
 732                     !begin_impl_frame_deadline_task_.IsCancelled());
 733   state->SetBoolean("poll_for_draw_triggers_task_",
 734                     !poll_for_draw_triggers_task_.IsCancelled());
 735   state->SetBoolean("advance_commit_state_task_",
 736                     !advance_commit_state_task_.IsCancelled());
 737   state->BeginDictionary("begin_impl_frame_args");
 738   begin_impl_frame_args_.AsValueInto(state);
 739   state->EndDictionary();
 740
 741   state->EndDictionary();
 742
 743   state->BeginDictionary("client_state");
 744   state->SetDouble("draw_duration_estimate_ms",
 745                    client_->DrawDurationEstimate().InMillisecondsF());
 746   state->SetDouble(
 747       "begin_main_frame_to_commit_duration_estimate_ms",
 748       client_->BeginMainFrameToCommitDurationEstimate().InMillisecondsF());
 749   state->SetDouble(
 750       "commit_to_activate_duration_estimate_ms",
 751       client_->CommitToActivateDurationEstimate().InMillisecondsF());
 752   state->EndDictionary();
 753 }
 754
 755 bool Scheduler::CanCommitAndActivateBeforeDeadline() const {
 756   // Check if the main thread computation and commit can be finished before the
 757   // impl thread's deadline.
 758   base::TimeTicks estimated_draw_time =
 759       begin_impl_frame_args_.frame_time +
 760       client_->BeginMainFrameToCommitDurationEstimate() +
 761       client_->CommitToActivateDurationEstimate();
 762
 763   TRACE_EVENT2(
 764       TRACE_DISABLED_BY_DEFAULT("cc.debug.scheduler"),
 765       "CanCommitAndActivateBeforeDeadline",
 766       "time_left_after_drawing_ms",
 767       (begin_impl_frame_args_.deadline - estimated_draw_time).InMillisecondsF(),
 768       "state",
 769       AsValue());
 770
 771   return estimated_draw_time < begin_impl_frame_args_.deadline;
 772 }
 773
 774 bool Scheduler::IsBeginMainFrameSentOrStarted() const {
 775   return (state_machine_.commit_state() ==
 776               SchedulerStateMachine::COMMIT_STATE_BEGIN_MAIN_FRAME_SENT ||
 777           state_machine_.commit_state() ==
 778               SchedulerStateMachine::COMMIT_STATE_BEGIN_MAIN_FRAME_STARTED);
 779 }
 780
 781 }  // namespace cc