Add DisplayScheduler for Surfaces

cc/surfaces/display_scheduler.cc

+// Copyright 2015 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 "cc/surfaces/display_scheduler.h"
+
+#include <vector>
+
+#include "base/stl_util.h"
+#include "base/trace_event/trace_event.h"
+#include "cc/output/output_surface.h"
+#include "ui/gfx/frame_time.h"
+
+namespace cc {
+
+DisplayScheduler::DisplayScheduler(
+    DisplaySchedulerClient* client,
+    BeginFrameSource* begin_frame_source,
+    scoped_refptr<base::SingleThreadTaskRunner> task_runner,
+    int max_pending_swaps)
+    : client_(client),
+      begin_frame_source_(begin_frame_source),
+      task_runner_(task_runner),
+      output_surface_lost_(false),
+      resources_locked_by_browser_(true),
+      inside_begin_frame_deadline_interval_(false),
+      needs_draw_(false),
+      entire_display_damaged_(false),
+      all_active_surfaces_ready_to_draw_(false),
+      pending_swaps_(0),
+      max_pending_swaps_(max_pending_swaps),
+      weak_ptr_factory_(this) {
+  begin_frame_source_->AddObserver(this);
+  begin_frame_deadline_closure_ = base::Bind(
+      &DisplayScheduler::OnBeginFrameDeadline, weak_ptr_factory_.GetWeakPtr());
+}
+
+DisplayScheduler::~DisplayScheduler() {
+  begin_frame_source_->RemoveObserver(this);
+}
+
+// If we try to draw when the Browser has locked it's resources, the
+// draw will fail.
+void DisplayScheduler::SetResourcesLockedByBrowser(bool locked) {
+  resources_locked_by_browser_ = locked;
+  ScheduleBeginFrameDeadline();
+}
+
+// Notification that there was a resize or the root surface changed and
+// that we should just draw immediately.
+void DisplayScheduler::EntireDisplayDamaged() {
+  TRACE_EVENT0("cc", "DisplayScheduler::EntireDisplayDamaged");
+  needs_draw_ = true;
+  entire_display_damaged_ = true;
+  ScheduleBeginFrameDeadline();
+}
+
+// Indicates that there was damage to one of the surfaces.
+// Has some logic to wait for multiple active surfaces before
+// triggering the deadline.
+void DisplayScheduler::SurfaceDamaged(SurfaceId surface_id) {
+  TRACE_EVENT1("cc", "DisplayScheduler::SurfaceDamaged", "surface_id",
+               surface_id.id);
+
+  needs_draw_ = true;
+
+  surface_ids_damaged_.insert(surface_id);
+
+  // TODO(mithro): Use hints from SetNeedsBeginFrames.
+  all_active_surfaces_ready_to_draw_ = base::STLIncludes(
+      surface_ids_damaged_, surface_ids_to_expect_damage_from_);
+
+  begin_frame_source_->SetNeedsBeginFrames(!output_surface_lost_);
+  ScheduleBeginFrameDeadline();
+}
+
+void DisplayScheduler::OutputSurfaceLost() {
+  TRACE_EVENT0("cc", "DisplayScheduler::OutputSurfaceLost");
+  output_surface_lost_ = true;
+  begin_frame_source_->SetNeedsBeginFrames(false);
+  ScheduleBeginFrameDeadline();
+}
+
+void DisplayScheduler::DrawAndSwap() {
+  TRACE_EVENT0("cc", "DisplayScheduler::DrawAndSwap");
+  DCHECK_LT(pending_swaps_, max_pending_swaps_);
+  DCHECK(!output_surface_lost_);
+
+  needs_draw_ = false;
+  entire_display_damaged_ = false;
+  all_active_surfaces_ready_to_draw_ = false;
+
+  client_->DrawAndSwap();
+
+  surface_ids_to_expect_damage_from_ =
+      base::STLSetIntersection<std::vector<SurfaceId>>(

[brianderson, 2015/04/07 02:32:19]

Changed this to an intersection of the last two frames so we only count 60fps
sources as being active.

+          surface_ids_damaged_, surface_ids_damaged_prev_);
+
+  surface_ids_damaged_prev_.swap(surface_ids_damaged_);
+  surface_ids_damaged_.clear();
+}
+
+bool DisplayScheduler::OnBeginFrameMixInDelegate(const BeginFrameArgs& args) {
+  TRACE_EVENT1("cc", "DisplayScheduler::BeginFrame", "args", args.AsValue());
+
+  // If we get another BeginFrame before the previous deadline,
+  // synchronously trigger the previous deadline before progressing.
+  if (inside_begin_frame_deadline_interval_) {
+    OnBeginFrameDeadline();
+  }
+
+  // Schedule the deadline.
+  current_begin_frame_args_ = args;
+  current_begin_frame_args_.deadline -=
+      BeginFrameArgs::DefaultEstimatedParentDrawTime();
+  inside_begin_frame_deadline_interval_ = true;
+  ScheduleBeginFrameDeadline();
+
+  return true;
+}
+
+base::TimeTicks DisplayScheduler::DesiredBeginFrameDeadlineTime() {
+  if (output_surface_lost_) {
+    TRACE_EVENT_INSTANT0("cc", "Lost output surface", TRACE_EVENT_SCOPE_THREAD);
+    return base::TimeTicks();
+  }
+
+  if (pending_swaps_ >= max_pending_swaps_) {
+    TRACE_EVENT_INSTANT0("cc", "Swap throttled", TRACE_EVENT_SCOPE_THREAD);
+    return current_begin_frame_args_.frame_time +
+           current_begin_frame_args_.interval;
+  }
+
+  if (resources_locked_by_browser_) {
+    TRACE_EVENT_INSTANT0("cc", "Resources locked by Browser",
+                         TRACE_EVENT_SCOPE_THREAD);
+    return current_begin_frame_args_.frame_time +
+           current_begin_frame_args_.interval;
+  }
+
+  if (entire_display_damaged_) {
+    TRACE_EVENT_INSTANT0("cc", "Entire display damaged",
+                         TRACE_EVENT_SCOPE_THREAD);
+    return base::TimeTicks();
+  }
+
+  if (all_active_surfaces_ready_to_draw_) {
+    TRACE_EVENT_INSTANT0("cc", "Active surfaces ready",
+                         TRACE_EVENT_SCOPE_THREAD);
+    return base::TimeTicks();
+  }
+
+  if (needs_draw_) {
+    TRACE_EVENT_INSTANT0("cc", "More damage expected soon",
+                         TRACE_EVENT_SCOPE_THREAD);
+    return current_begin_frame_args_.deadline;
+  }
+
+  TRACE_EVENT_INSTANT0("cc", "No damage yet", TRACE_EVENT_SCOPE_THREAD);
+  return current_begin_frame_args_.frame_time +
+         current_begin_frame_args_.interval;
+}
+
+void DisplayScheduler::ScheduleBeginFrameDeadline() {
+  TRACE_EVENT0("cc", "DisplayScheduler::ScheduleBeginFrameDeadline");
+
+  // We need to wait for the next BeginFrame before scheduling a deadline.
+  if (!inside_begin_frame_deadline_interval_) {
+    TRACE_EVENT_INSTANT0("cc", "Waiting for next BeginFrame",
+                         TRACE_EVENT_SCOPE_THREAD);
+    DCHECK(begin_frame_deadline_task_.IsCancelled());
+    return;
+  }
+
+  // Determine the deadline we want to use.
+  base::TimeTicks desired_deadline = DesiredBeginFrameDeadlineTime();
+
+  // Avoid re-scheduling the deadline if it's already correctly scheduled.
+  if (!begin_frame_deadline_task_.IsCancelled() &&
+      desired_deadline == begin_frame_deadline_task_time_)
+    return;
+
+  // Schedule the deadline.
+  begin_frame_deadline_task_time_ = desired_deadline;
+  begin_frame_deadline_task_.Cancel();
+  begin_frame_deadline_task_.Reset(begin_frame_deadline_closure_);
+
+  base::TimeDelta delta =
+      std::max(base::TimeDelta(), desired_deadline - base::TimeTicks::Now());
+  task_runner_->PostDelayedTask(FROM_HERE,
+                                begin_frame_deadline_task_.callback(), delta);
+}
+
+void DisplayScheduler::OnBeginFrameDeadline() {
+  TRACE_EVENT0("cc", "DisplayScheduler::OnBeginFrameDeadline");
+  begin_frame_deadline_task_.Cancel();
+  begin_frame_deadline_task_time_ = base::TimeTicks();
+
+  if (needs_draw_ && !output_surface_lost_) {
+    // TODO(brianderson): Figure out why supressing DrawAndSwap while

[brianderson, 2015/04/07 02:32:19]

jbauman: Any idea why suppressing DrawAndSwap while resources_locked_by_browser_
is true would cause a hang?

It's not really needed to make the scheduler work well, but it's a bit
unexpected.

[jbauman, 2015/04/07 23:51:29]

Hopefully because resources_locked_by_browser_ was inverted.

[brianderson, 2015/04/08 02:23:02]

Magic! Thanks debugging my code. =)

I fixed resources_locked_by_browser_ and removed the TODOs.

+    // resources_locked_by_browser_ is true causes hangs.
+    if (pending_swaps_ < max_pending_swaps_)
+      DrawAndSwap();
+  } else {
+    begin_frame_source_->SetNeedsBeginFrames(false);
+  }
+
+  inside_begin_frame_deadline_interval_ = false;
+  begin_frame_source_->DidFinishFrame(0);
+}
+
+void DisplayScheduler::DidSwapBuffers() {
+  pending_swaps_++;
+  TRACE_EVENT1("cc", "DisplayScheduler::DidSwapBuffers", "pending_frames",
+               pending_swaps_);
+}
+
+void DisplayScheduler::DidSwapBuffersComplete() {
+  pending_swaps_--;
+  TRACE_EVENT1("cc", "DisplayScheduler::DidSwapBuffersComplete",
+               "pending_frames", pending_swaps_);
+  ScheduleBeginFrameDeadline();
+}
+
+}  // namespace cc