cc: Move pre-decodes to background worker.

cc/tiles/tile_manager.cc

 // Copyright 2012 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/tiles/tile_manager.h"
 
 #include <stddef.h>
 #include <stdint.h>
 
 #include <algorithm>
@@ skipping 475 matching lines @@
 
   if (!tile_task_manager_) {
     TRACE_EVENT_INSTANT0("cc", "PrepareTiles aborted",
                          TRACE_EVENT_SCOPE_THREAD);
     return false;
   }
 
   signals_.reset();
   global_state_ = state;
 
+  // Ensure that we don't schedule any decode work for checkered images until
+  // the raster work for visible tiles is done.

[vmpstr, 2017/06/22 16:57:58]

Can you elaborate a bit more by stating when exactly we'll allow decodes (ie
when required for {draw,activate} tiles are done if there are any... in any
case, this is done when we issue a draw/activate signal)

[Khushal, 2017/06/22 20:11:51]

Done.

+  checker_image_tracker_.SetNoDecodesAllowed();
+
   // We need to call CheckForCompletedTasks() once in-between each call
   // to ScheduleTasks() to prevent canceled tasks from being scheduled.
   if (!did_check_for_completed_tasks_since_last_schedule_tasks_) {
     tile_task_manager_->CheckForCompletedTasks();
     did_check_for_completed_tasks_since_last_schedule_tasks_ = true;
   }
 
   PrioritizedWorkToSchedule prioritized_work = AssignGpuMemoryToTiles();
 
   // Inform the client that will likely require a draw if the highest priority
   // tile that will be rasterized is required for draw.
   client_->SetIsLikelyToRequireADraw(
       !prioritized_work.tiles_to_raster.empty() &&
       prioritized_work.tiles_to_raster.front().tile()->required_for_draw());
 
   // Schedule tile tasks.
-  ScheduleTasks(prioritized_work);
+  ScheduleTasks(std::move(prioritized_work));
 
   TRACE_EVENT_INSTANT1("cc", "DidPrepareTiles", TRACE_EVENT_SCOPE_THREAD,
                        "state", BasicStateAsValue());
   return true;
 }
 
 void TileManager::Flush() {
   TRACE_EVENT0("cc", "TileManager::Flush");
 
   if (!tile_task_manager_) {
@@ skipping 175 matching lines @@
     // checker-images. If this tile does not need raster, process it only to
     // build the decode queue for checkered images.
     // Note that performing this check after the solid color analysis is not
     // necessary for correctness.
     if (!tile->draw_info().NeedsRaster()) {
       DCHECK(tile->draw_info().is_checker_imaged());
       DCHECK(prioritized_tile.should_decode_checkered_images_for_tile());
 
       AddCheckeredImagesToDecodeQueue(
           prioritized_tile, raster_color_space,
+          CheckerImageTracker::DecodeType::kRaster,
           &work_to_schedule.checker_image_decode_queue);
       continue;
     }
 
     // We won't be able to schedule this tile, so break out early.
     if (work_to_schedule.tiles_to_raster.size() >=
         scheduled_raster_task_limit_) {
       all_tiles_that_need_to_be_rasterized_are_scheduled_ = false;
       break;
     }
@@ skipping 38 matching lines @@
 
     // If the tile has a scheduled task that will rasterize a resource with
     // checker-imaged content, add those images to the decode queue. Note that
     // we add all images as we process the raster priority queue to ensure that
     // images are added to the decode queue in raster priority order.
     if (tile->HasRasterTask()) {
       if (tile->raster_task_scheduled_with_checker_images() &&
           prioritized_tile.should_decode_checkered_images_for_tile()) {
         AddCheckeredImagesToDecodeQueue(
             prioritized_tile, raster_color_space,
+            CheckerImageTracker::DecodeType::kRaster,
             &work_to_schedule.checker_image_decode_queue);
       }
     } else {
       // Creating the raster task here will acquire resources, but
       // this resource usage has already been accounted for above.
       tile->raster_task_ =
           CreateRasterTask(prioritized_tile, client_->GetRasterColorSpace(),
                            &work_to_schedule.checker_image_decode_queue);
     }
 
@@ skipping 22 matching lines @@
         break;
 
       if (!prioritized_tile.should_decode_checkered_images_for_tile())
         continue;
 
       Tile* tile = prioritized_tile.tile();
       if (tile->draw_info().is_checker_imaged() ||
           tile->raster_task_scheduled_with_checker_images()) {
         AddCheckeredImagesToDecodeQueue(
             prioritized_tile, raster_color_space,
+            CheckerImageTracker::DecodeType::kRaster,
             &work_to_schedule.checker_image_decode_queue);
       }
     }
   }
 
   UMA_HISTOGRAM_BOOLEAN("TileManager.ExceededMemoryBudget",
                         !had_enough_memory_to_schedule_tiles_needed_now);
   did_oom_on_last_assign_ = !had_enough_memory_to_schedule_tiles_needed_now;
 
   memory_stats_from_last_assign_.total_budget_in_bytes =
@@ skipping 49 matching lines @@
     if (checker_image_tracker_.ShouldCheckerImage(draw_image, tree))
       checkered_images->push_back(draw_image.paint_image());
     else
       sync_decoded_images->push_back(draw_image);
   }
 }
 
 void TileManager::AddCheckeredImagesToDecodeQueue(
     const PrioritizedTile& prioritized_tile,
     const gfx::ColorSpace& raster_color_space,
+    CheckerImageTracker::DecodeType decode_type,
     CheckerImageTracker::ImageDecodeQueue* image_decode_queue) {
   Tile* tile = prioritized_tile.tile();
   std::vector<DrawImage> images_in_tile;
   prioritized_tile.raster_source()->GetDiscardableImagesInRect(
       tile->enclosing_layer_rect(), tile->raster_transform().scale(),
       raster_color_space, &images_in_tile);
   WhichTree tree = tile->tiling()->tree();
 
   for (auto& draw_image : images_in_tile) {
-    if (checker_image_tracker_.ShouldCheckerImage(draw_image, tree))
-      image_decode_queue->push_back(draw_image.paint_image());
+    if (checker_image_tracker_.ShouldCheckerImage(draw_image, tree)) {
+      image_decode_queue->push_back(CheckerImageTracker::ImageDecodeRequest(
+          draw_image.paint_image(), decode_type));
+    }
   }
 }
 
-void TileManager::ScheduleTasks(
-    const PrioritizedWorkToSchedule& work_to_schedule) {
+void TileManager::ScheduleTasks(PrioritizedWorkToSchedule work_to_schedule) {
   const std::vector<PrioritizedTile>& tiles_that_need_to_be_rasterized =
       work_to_schedule.tiles_to_raster;
   TRACE_EVENT1("cc", "TileManager::ScheduleTasks", "count",
                tiles_that_need_to_be_rasterized.size());
 
   DCHECK(did_check_for_completed_tasks_since_last_schedule_tasks_);
 
   if (!has_scheduled_tile_tasks_) {
     TRACE_EVENT_ASYNC_BEGIN0("cc", "ScheduledTasks", this);
   }
@@ skipping 59 matching lines @@
         tile->required_for_draw() || tile->required_for_activation() ||
         prioritized_tile.priority().priority_bin == TilePriority::NOW;
     InsertNodesForRasterTask(&graph_, task, task->dependencies(), priority++,
                              use_foreground_category);
   }
 
   const std::vector<PrioritizedTile>& tiles_to_process_for_images =
       work_to_schedule.tiles_to_process_for_images;
   std::vector<DrawImage> new_locked_images;
   for (const PrioritizedTile& prioritized_tile : tiles_to_process_for_images) {
-    Tile* tile = prioritized_tile.tile();
+    std::vector<DrawImage> sync_decoded_images;
+    std::vector<PaintImage> checkered_images;
+    PartitionImagesForCheckering(prioritized_tile, raster_color_space,
+                                 &sync_decoded_images, &checkered_images);
 
-    // TODO(khushalsagar): Send these images to the ImageDecodeService, through
-    // the CheckerImageTracker as well. See crbug.com/691087.
-    std::vector<DrawImage> images;
-    prioritized_tile.raster_source()->GetDiscardableImagesInRect(
-        tile->enclosing_layer_rect(), tile->raster_transform().scale(),
-        raster_color_space, &images);
-    new_locked_images.insert(new_locked_images.end(), images.begin(),
-                             images.end());
+    // Add the sync decoded images to |new_locked_images| so they can be added
+    // to the task graph.
+    new_locked_images.insert(new_locked_images.end(),
+                             sync_decoded_images.begin(),
+                             sync_decoded_images.end());
+
+    // For checkered-images, send them to the decode service.
+    for (auto& image : checkered_images) {
+      work_to_schedule.checker_image_decode_queue.push_back(
+          CheckerImageTracker::ImageDecodeRequest(
+              std::move(image), CheckerImageTracker::DecodeType::kPreDecode));
+    }
   }
 
   // TODO(vmpstr): SOON is misleading here, but these images can come from
   // several diffent tiles. Rethink what we actually want to trace here. Note
   // that I'm using SOON, since it can't be NOW (these are prepaint).
   ImageDecodeCache::TracingInfo tracing_info(
       prepare_tiles_count_, TilePriority::SOON,
       ImageDecodeCache::TaskType::kInRaster);
   std::vector<scoped_refptr<TileTask>> new_locked_image_tasks =
       image_controller_.SetPredecodeImages(std::move(new_locked_images),
@@ skipping 104 matching lines @@
     std::vector<PaintImage> checkered_images;
     PartitionImagesForCheckering(prioritized_tile, color_space,
                                  &sync_decoded_images, &checkered_images);
     for (const auto& image : checkered_images) {
       playback_settings.images_to_skip.insert(image.sk_image()->uniqueID());
 
       // This can be the case for tiles on the active tree that will be replaced
       // or are occluded on the pending tree. While we still need to continue
       // skipping images for these tiles, we don't need to decode them since
       // they will not be required on the next active tree.
-      if (prioritized_tile.should_decode_checkered_images_for_tile())
-        checker_image_decode_queue->push_back(image);
+      if (prioritized_tile.should_decode_checkered_images_for_tile()) {
+        checker_image_decode_queue->push_back(
+            CheckerImageTracker::ImageDecodeRequest(
+                image, CheckerImageTracker::DecodeType::kRaster));
+      }
     }
   }
 
   // We can skip the image hijack canvas if we have no images, or no images to
   // skip during raster.
   playback_settings.use_image_hijack_canvas =
       !sync_decoded_images.empty() || !playback_settings.images_to_skip.empty();
 
   bool has_checker_images = !playback_settings.images_to_skip.empty();
   tile->set_raster_task_scheduled_with_checker_images(has_checker_images);
@@ skipping 178 matching lines @@
       !signals_.did_notify_all_tile_tasks_completed) {
     signals_.all_tile_tasks_completed = false;
     if (!has_scheduled_tile_tasks_) {
       TRACE_EVENT0(
           TRACE_DISABLED_BY_DEFAULT("cc.debug"),
           "TileManager::CheckAndIssueSignals - all tile tasks completed");
       signals_.did_notify_all_tile_tasks_completed = true;
       client_->NotifyAllTileTasksCompleted();
     }
   }
+
+  // Allow decodes for rasterized tiles if all required for draw/activate tiles
+  // are done. And pre-decode tiles once all tile tasks are done.

[vmpstr, 2017/06/22 16:57:57]

Can you elaborate again to just say that the order is important since all of
those signals could have become true, and if that's the case we want to allow
the most decodes.

[Khushal, 2017/06/22 20:11:51]

Done.

+  if (signals_.did_notify_all_tile_tasks_completed) {
+    checker_image_tracker_.SetMaxDecodePriorityAllowed(
+        CheckerImageTracker::DecodeType::kPreDecode);
+  } else if (signals_.did_notify_ready_to_activate &&
+             signals_.did_notify_ready_to_draw) {
+    checker_image_tracker_.SetMaxDecodePriorityAllowed(
+        CheckerImageTracker::DecodeType::kRaster);
+  }
 }
 
 void TileManager::CheckIfMoreTilesNeedToBePrepared() {
   tile_task_manager_->CheckForCompletedTasks();
   did_check_for_completed_tasks_since_last_schedule_tasks_ = true;
 
   // When OOM, keep re-assigning memory until we reach a steady state
   // where top-priority tiles are initialized.
   PrioritizedWorkToSchedule work_to_schedule = AssignGpuMemoryToTiles();
 
   // Inform the client that will likely require a draw if the highest priority
   // tile that will be rasterized is required for draw.
   client_->SetIsLikelyToRequireADraw(
       !work_to_schedule.tiles_to_raster.empty() &&
       work_to_schedule.tiles_to_raster.front().tile()->required_for_draw());
 
   // |tiles_that_need_to_be_rasterized| will be empty when we reach a
   // steady memory state. Keep scheduling tasks until we reach this state.
   if (!work_to_schedule.tiles_to_raster.empty()) {
-    ScheduleTasks(work_to_schedule);
+    ScheduleTasks(std::move(work_to_schedule));
     return;
   }
 
   // If we're not in SMOOTHNESS_TAKES_PRIORITY  mode, we should unlock all
   // images since we're technically going idle here at least for this frame.
   if (global_state_.tree_priority != SMOOTHNESS_TAKES_PRIORITY) {
     image_controller_.SetPredecodeImages(std::vector<DrawImage>(),
                                          ImageDecodeCache::TracingInfo());
     locked_image_tasks_.clear();
   }
@@ skipping 320 matching lines @@
   all_tile_tasks_completed = false;
   did_notify_all_tile_tasks_completed = false;
 }
 
 TileManager::PrioritizedWorkToSchedule::PrioritizedWorkToSchedule() = default;
 TileManager::PrioritizedWorkToSchedule::PrioritizedWorkToSchedule(
     PrioritizedWorkToSchedule&& other) = default;
 TileManager::PrioritizedWorkToSchedule::~PrioritizedWorkToSchedule() = default;
 
 }  // namespace cc