cc/surfaces/display_scheduler.cc

   1 // Copyright 2015 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/surfaces/display_scheduler.h"
   6
   7 #include <vector>
   8
   9 #include "base/stl_util.h"
  10 #include "base/trace_event/trace_event.h"
  11 #include "cc/output/output_surface.h"
  12
  13 namespace cc {
  14
  15 DisplayScheduler::DisplayScheduler(DisplaySchedulerClient* client,
  16                                    BeginFrameSource* begin_frame_source,
  17                                    base::SingleThreadTaskRunner* task_runner,
  18                                    int max_pending_swaps)
  19     : client_(client),
  20       begin_frame_source_(begin_frame_source),
  21       task_runner_(task_runner),
  22       output_surface_lost_(false),
  23       root_surface_resources_locked_(true),
  24       inside_begin_frame_deadline_interval_(false),
  25       needs_draw_(false),
  26       entire_display_damaged_(false),
  27       all_active_child_surfaces_ready_to_draw_(false),
  28       pending_swaps_(0),
  29       max_pending_swaps_(max_pending_swaps),
  30       root_surface_damaged_(false),
  31       expect_damage_from_root_surface_(false),
  32       weak_ptr_factory_(this) {
  33   begin_frame_source_->AddObserver(this);
  34   begin_frame_deadline_closure_ = base::Bind(
  35       &DisplayScheduler::OnBeginFrameDeadline, weak_ptr_factory_.GetWeakPtr());
  36 }
  37
  38 DisplayScheduler::~DisplayScheduler() {
  39   begin_frame_source_->RemoveObserver(this);
  40 }
  41
  42 // If we try to draw when the root surface resources are locked, the
  43 // draw will fail.
  44 void DisplayScheduler::SetRootSurfaceResourcesLocked(bool locked) {
  45   root_surface_resources_locked_ = locked;
  46   ScheduleBeginFrameDeadline();
  47 }
  48
  49 // This is used to force an immediate swap before a resize.
  50 void DisplayScheduler::ForceImmediateSwapIfPossible() {
  51   bool in_begin = inside_begin_frame_deadline_interval_;
  52   AttemptDrawAndSwap();
  53   if (in_begin)
  54     begin_frame_source_->DidFinishFrame(0);
  55 }
  56
  57 // Notification that there was a resize or the root surface changed and
  58 // that we should just draw immediately.
  59 void DisplayScheduler::EntireDisplayDamaged(SurfaceId root_surface_id) {
  60   TRACE_EVENT0("cc", "DisplayScheduler::EntireDisplayDamaged");
  61   needs_draw_ = true;
  62   entire_display_damaged_ = true;
  63   root_surface_id_ = root_surface_id;
  64
  65   begin_frame_source_->SetNeedsBeginFrames(!output_surface_lost_);
  66   ScheduleBeginFrameDeadline();
  67 }
  68
  69 // Indicates that there was damage to one of the surfaces.
  70 // Has some logic to wait for multiple active surfaces before
  71 // triggering the deadline.
  72 void DisplayScheduler::SurfaceDamaged(SurfaceId surface_id) {
  73   TRACE_EVENT1("cc", "DisplayScheduler::SurfaceDamaged", "surface_id",
  74                surface_id.id);
  75
  76   needs_draw_ = true;
  77
  78   if (surface_id == root_surface_id_) {
  79     root_surface_damaged_ = true;
  80   } else {
  81     child_surface_ids_damaged_.insert(surface_id);
  82
  83     // TODO(mithro): Use hints from SetNeedsBeginFrames and SwapAborts.
  84     all_active_child_surfaces_ready_to_draw_ = base::STLIncludes(
  85         child_surface_ids_damaged_, child_surface_ids_to_expect_damage_from_);
  86   }
  87
  88   begin_frame_source_->SetNeedsBeginFrames(!output_surface_lost_);
  89   ScheduleBeginFrameDeadline();
  90 }
  91
  92 void DisplayScheduler::OutputSurfaceLost() {
  93   TRACE_EVENT0("cc", "DisplayScheduler::OutputSurfaceLost");
  94   output_surface_lost_ = true;
  95   begin_frame_source_->SetNeedsBeginFrames(false);
  96   ScheduleBeginFrameDeadline();
  97 }
  98
  99 void DisplayScheduler::DrawAndSwap() {
 100   TRACE_EVENT0("cc", "DisplayScheduler::DrawAndSwap");
 101   DCHECK_LT(pending_swaps_, max_pending_swaps_);
 102   DCHECK(!output_surface_lost_);
 103
 104   bool success = client_->DrawAndSwap();
 105   if (!success)
 106     return;
 107
 108   child_surface_ids_to_expect_damage_from_ =
 109       base::STLSetIntersection<std::vector<SurfaceId>>(
 110           child_surface_ids_damaged_, child_surface_ids_damaged_prev_);
 111
 112   child_surface_ids_damaged_prev_.swap(child_surface_ids_damaged_);
 113   child_surface_ids_damaged_.clear();
 114
 115   needs_draw_ = false;
 116   entire_display_damaged_ = false;
 117   all_active_child_surfaces_ready_to_draw_ =
 118       child_surface_ids_to_expect_damage_from_.empty();
 119
 120   expect_damage_from_root_surface_ = root_surface_damaged_;
 121   root_surface_damaged_ = false;
 122 }
 123
 124 bool DisplayScheduler::OnBeginFrameDerivedImpl(const BeginFrameArgs& args) {
 125   base::TimeTicks now = base::TimeTicks::Now();
 126   TRACE_EVENT2("cc", "DisplayScheduler::BeginFrame", "args", args.AsValue(),
 127                "now", now);
 128
 129   // If we get another BeginFrame before the previous deadline,
 130   // synchronously trigger the previous deadline before progressing.
 131   if (inside_begin_frame_deadline_interval_) {
 132     OnBeginFrameDeadline();
 133   }
 134
 135   // Schedule the deadline.
 136   current_begin_frame_args_ = args;
 137   current_begin_frame_args_.deadline -=
 138       BeginFrameArgs::DefaultEstimatedParentDrawTime();
 139   inside_begin_frame_deadline_interval_ = true;
 140   ScheduleBeginFrameDeadline();
 141
 142   return true;
 143 }
 144
 145 base::TimeTicks DisplayScheduler::DesiredBeginFrameDeadlineTime() {
 146   if (output_surface_lost_) {
 147     TRACE_EVENT_INSTANT0("cc", "Lost output surface", TRACE_EVENT_SCOPE_THREAD);
 148     return base::TimeTicks();
 149   }
 150
 151   if (pending_swaps_ >= max_pending_swaps_) {
 152     TRACE_EVENT_INSTANT0("cc", "Swap throttled", TRACE_EVENT_SCOPE_THREAD);
 153     return current_begin_frame_args_.deadline;
 154   }
 155
 156   if (!needs_draw_) {
 157     TRACE_EVENT_INSTANT0("cc", "No damage yet", TRACE_EVENT_SCOPE_THREAD);
 158     return current_begin_frame_args_.frame_time +
 159            current_begin_frame_args_.interval;
 160   }
 161
 162   if (root_surface_resources_locked_) {
 163     TRACE_EVENT_INSTANT0("cc", "Root surface resources locked",
 164                          TRACE_EVENT_SCOPE_THREAD);
 165     return current_begin_frame_args_.frame_time +
 166            current_begin_frame_args_.interval;
 167   }
 168
 169   // TODO(mithro): Be smarter about resize deadlines.
 170   if (entire_display_damaged_) {
 171     TRACE_EVENT_INSTANT0("cc", "Entire display damaged",
 172                          TRACE_EVENT_SCOPE_THREAD);
 173     return base::TimeTicks();
 174   }
 175
 176   bool root_ready_to_draw =
 177       !expect_damage_from_root_surface_ || root_surface_damaged_;
 178
 179   if (all_active_child_surfaces_ready_to_draw_ && root_ready_to_draw) {
 180     TRACE_EVENT_INSTANT0("cc", "All active surfaces ready",
 181                          TRACE_EVENT_SCOPE_THREAD);
 182     return base::TimeTicks();
 183   }
 184
 185   // Use an earlier deadline if we are only waiting for the root surface
 186   // in case our expect_damage_from_root_surface heuristic is incorrect.
 187   // TODO(mithro): Replace this with SetNeedsBeginFrame and SwapAbort
 188   // logic.
 189   if (all_active_child_surfaces_ready_to_draw_ &&
 190       expect_damage_from_root_surface_) {
 191     TRACE_EVENT_INSTANT0("cc", "Waiting for damage from root surface",
 192                          TRACE_EVENT_SCOPE_THREAD);
 193     // This adjusts the deadline by DefaultEstimatedParentDrawTime for
 194     // a second time. The first one represented the Surfaces draw to display
 195     // latency. This one represents root surface commit+raster+draw latency.
 196     // We treat the root surface differently since it lives on the same thread
 197     // as Surfaces and waiting for it too long may push out the Surfaces draw.
 198     // If we also assume the root surface is fast to start a commit after the
 199     // beginning of a frame, it'll have a chance to lock its resources, which
 200     // will cause us to wait for it to unlock its resources above.
 201     // TODO(mithro): Replace hard coded estimates.
 202     return current_begin_frame_args_.deadline -
 203            BeginFrameArgs::DefaultEstimatedParentDrawTime();
 204   }
 205
 206   TRACE_EVENT_INSTANT0("cc", "More damage expected soon",
 207                        TRACE_EVENT_SCOPE_THREAD);
 208   return current_begin_frame_args_.deadline;
 209 }
 210
 211 void DisplayScheduler::ScheduleBeginFrameDeadline() {
 212   TRACE_EVENT0("cc", "DisplayScheduler::ScheduleBeginFrameDeadline");
 213
 214   // We need to wait for the next BeginFrame before scheduling a deadline.
 215   if (!inside_begin_frame_deadline_interval_) {
 216     TRACE_EVENT_INSTANT0("cc", "Waiting for next BeginFrame",
 217                          TRACE_EVENT_SCOPE_THREAD);
 218     DCHECK(begin_frame_deadline_task_.IsCancelled());
 219     return;
 220   }
 221
 222   // Determine the deadline we want to use.
 223   base::TimeTicks desired_deadline = DesiredBeginFrameDeadlineTime();
 224
 225   // Avoid re-scheduling the deadline if it's already correctly scheduled.
 226   if (!begin_frame_deadline_task_.IsCancelled() &&
 227       desired_deadline == begin_frame_deadline_task_time_) {
 228     TRACE_EVENT_INSTANT0("cc", "Using existing deadline",
 229                          TRACE_EVENT_SCOPE_THREAD);
 230     return;
 231   }
 232
 233   // Schedule the deadline.
 234   begin_frame_deadline_task_time_ = desired_deadline;
 235   begin_frame_deadline_task_.Cancel();
 236   begin_frame_deadline_task_.Reset(begin_frame_deadline_closure_);
 237
 238   base::TimeDelta delta =
 239       std::max(base::TimeDelta(), desired_deadline - base::TimeTicks::Now());
 240   task_runner_->PostDelayedTask(FROM_HERE,
 241                                 begin_frame_deadline_task_.callback(), delta);
 242   TRACE_EVENT2("cc", "Using new deadline", "delta", delta.ToInternalValue(),
 243                "desired_deadline", desired_deadline);
 244 }
 245
 246 void DisplayScheduler::AttemptDrawAndSwap() {
 247   inside_begin_frame_deadline_interval_ = false;
 248   begin_frame_deadline_task_.Cancel();
 249   begin_frame_deadline_task_time_ = base::TimeTicks();
 250
 251   if (needs_draw_ && !output_surface_lost_) {
 252     if (pending_swaps_ < max_pending_swaps_ && !root_surface_resources_locked_)
 253       DrawAndSwap();
 254   } else {
 255     // We are going idle, so reset expectations.
 256     child_surface_ids_to_expect_damage_from_.clear();
 257     child_surface_ids_damaged_prev_.clear();
 258     child_surface_ids_damaged_.clear();
 259     all_active_child_surfaces_ready_to_draw_ = true;
 260     expect_damage_from_root_surface_ = false;
 261
 262     begin_frame_source_->SetNeedsBeginFrames(false);
 263   }
 264 }
 265
 266 void DisplayScheduler::OnBeginFrameDeadline() {
 267   TRACE_EVENT0("cc", "DisplayScheduler::OnBeginFrameDeadline");
 268
 269   AttemptDrawAndSwap();
 270   begin_frame_source_->DidFinishFrame(0);
 271 }
 272
 273 void DisplayScheduler::DidSwapBuffers() {
 274   pending_swaps_++;
 275   TRACE_EVENT1("cc", "DisplayScheduler::DidSwapBuffers", "pending_frames",
 276                pending_swaps_);
 277 }
 278
 279 void DisplayScheduler::DidSwapBuffersComplete() {
 280   pending_swaps_--;
 281   TRACE_EVENT1("cc", "DisplayScheduler::DidSwapBuffersComplete",
 282                "pending_frames", pending_swaps_);
 283   ScheduleBeginFrameDeadline();
 284 }
 285
 286 }  // namespace cc