Scheduler: Experiment with setting priorities based on frame origin.

Set the priority of same-origin loading task to high and the priority of
cross-origin tasks to low depending on the feature enabled.

Bug: 856158
Change-Id: I5bc2e17cf512ccae0cdd7a62d1afc61cc5b53cb7
Reviewed-on: https://chromium-review.googlesource.com/1112252
Commit-Queue: Farah Charab <farahcharab@chromium.org>
Reviewed-by: Robert Kaplow (OOO until 0730) <rkaplow@chromium.org>
Reviewed-by: Alex Clarke <alexclarke@chromium.org>
Reviewed-by: Alexander Timin <altimin@chromium.org>
Reviewed-by: Sami Kyöstilä <skyostil@chromium.org>
Cr-Commit-Position: refs/heads/master@{#577256}

testing/variations/fieldtrial_testing_config.json

@@ -2739,6 +2739,25 @@
             ]
         }
     ],
+    "OriginTypePriorityExperiment": [
+        {
+            "platforms": [
+                "windows",
+                "mac",
+                "chromeos",
+                "linux",
+                "android"
+            ],
+            "experiments": [
+                {
+                    "name": "LowPriorityForCrossOriginFrame",
+                    "enable_features": [
+                        "BlinkSchedulerLowPriorityForCrossOrigin"
+                    ]
+                }
+            ]
+        }
+    ],
     "OverflowIconsForMediaControls": [
         {
             "platforms": [

third_party/blink/renderer/platform/scheduler/child/features.h

@@ -100,6 +100,12 @@ const base::Feature kBestEffortPriorityForAdFrame{
 const base::Feature kUseResourceFetchPriority{
     "BlinkSchedulerResourceFetchPriority", base::FEATURE_DISABLED_BY_DEFAULT};
 
+// Enables setting the priority of cross-origin task queues to
+// low priority.
+const base::Feature kLowPriorityForCrossOrigin{
+    "BlinkSchedulerLowPriorityForCrossOrigin",
+    base::FEATURE_DISABLED_BY_DEFAULT};
+
 // Enables a chosen experiments only during the load use case.
 const base::Feature kExperimentOnlyWhenLoading{
     "BlinkSchedulerExperimentOnlyWhenLoading",

third_party/blink/renderer/platform/scheduler/main_thread/frame_scheduler_impl.cc

@@ -857,6 +857,12 @@ TaskQueue::QueuePriority FrameSchedulerImpl::ComputePriority(
         IsAdFrame()) {
       return TaskQueue::QueuePriority::kBestEffortPriority;
     }
+
+    if (main_thread_scheduler_->scheduling_settings()
+            .low_priority_cross_origin &&
+        IsCrossOrigin()) {
+      return TaskQueue::QueuePriority::kLowPriority;
+    }
   }
 
   return task_queue->queue_type() ==

third_party/blink/renderer/platform/scheduler/main_thread/frame_scheduler_impl_unittest.cc

@@ -1382,6 +1382,109 @@ TEST_F(
   EXPECT_EQ(task_queue->GetQueuePriority(), priority);
 }
 
+class LowPriorityCrossOriginTaskExperimentTest : public FrameSchedulerImplTest {
+ public:
+  LowPriorityCrossOriginTaskExperimentTest()
+      : FrameSchedulerImplTest({kLowPriorityForCrossOrigin},
+                               {kExperimentOnlyWhenLoading}) {}
+};
+
+TEST_F(LowPriorityCrossOriginTaskExperimentTest, FrameQueuesPriorities) {
+  EXPECT_FALSE(frame_scheduler_->IsCrossOrigin());
+
+  // Same Origin Task Queues.
+  EXPECT_EQ(LoadingTaskQueue()->GetQueuePriority(),
+            TaskQueue::QueuePriority::kNormalPriority);
+  EXPECT_EQ(LoadingControlTaskQueue()->GetQueuePriority(),
+            TaskQueue::QueuePriority::kHighPriority);
+  EXPECT_EQ(DeferrableTaskQueue()->GetQueuePriority(),
+            TaskQueue::QueuePriority::kNormalPriority);
+  EXPECT_EQ(ThrottleableTaskQueue()->GetQueuePriority(),
+            TaskQueue::QueuePriority::kNormalPriority);
+  EXPECT_EQ(PausableTaskQueue()->GetQueuePriority(),
+            TaskQueue::QueuePriority::kNormalPriority);
+  EXPECT_EQ(UnpausableTaskQueue()->GetQueuePriority(),
+            TaskQueue::QueuePriority::kNormalPriority);
+
+  frame_scheduler_->SetCrossOrigin(true);
+  EXPECT_TRUE(frame_scheduler_->IsCrossOrigin());
+
+  EXPECT_EQ(LoadingTaskQueue()->GetQueuePriority(),
+            TaskQueue::QueuePriority::kLowPriority);
+  EXPECT_EQ(LoadingControlTaskQueue()->GetQueuePriority(),
+            TaskQueue::QueuePriority::kLowPriority);
+  EXPECT_EQ(DeferrableTaskQueue()->GetQueuePriority(),
+            TaskQueue::QueuePriority::kLowPriority);
+  EXPECT_EQ(ThrottleableTaskQueue()->GetQueuePriority(),
+            TaskQueue::QueuePriority::kLowPriority);
+  EXPECT_EQ(PausableTaskQueue()->GetQueuePriority(),
+            TaskQueue::QueuePriority::kLowPriority);
+  EXPECT_EQ(UnpausableTaskQueue()->GetQueuePriority(),
+            TaskQueue::QueuePriority::kLowPriority);
+}
+
+class LowPriorityCrossOriginTaskDuringLoadingExperimentTest
+    : public FrameSchedulerImplTest {
+ public:
+  LowPriorityCrossOriginTaskDuringLoadingExperimentTest()
+      : FrameSchedulerImplTest(
+            {kLowPriorityForCrossOrigin, kExperimentOnlyWhenLoading},
+            {}) {}
+};
+
+TEST_F(LowPriorityCrossOriginTaskDuringLoadingExperimentTest,
+       FrameQueuesPriorities) {
+  // Main thread is in the loading use case.
+  scheduler_->DidStartProvisionalLoad(true);
+  EXPECT_TRUE(page_scheduler_->IsLoading());
+
+  EXPECT_EQ(LoadingTaskQueue()->GetQueuePriority(),
+            TaskQueue::QueuePriority::kNormalPriority);
+  EXPECT_EQ(LoadingControlTaskQueue()->GetQueuePriority(),
+            TaskQueue::QueuePriority::kHighPriority);
+  EXPECT_EQ(DeferrableTaskQueue()->GetQueuePriority(),
+            TaskQueue::QueuePriority::kNormalPriority);
+  EXPECT_EQ(ThrottleableTaskQueue()->GetQueuePriority(),
+            TaskQueue::QueuePriority::kNormalPriority);
+  EXPECT_EQ(PausableTaskQueue()->GetQueuePriority(),
+            TaskQueue::QueuePriority::kNormalPriority);
+  EXPECT_EQ(UnpausableTaskQueue()->GetQueuePriority(),
+            TaskQueue::QueuePriority::kNormalPriority);
+
+  frame_scheduler_->SetCrossOrigin(true);
+  EXPECT_TRUE(frame_scheduler_->IsCrossOrigin());
+
+  EXPECT_EQ(LoadingTaskQueue()->GetQueuePriority(),
+            TaskQueue::QueuePriority::kLowPriority);
+  EXPECT_EQ(LoadingControlTaskQueue()->GetQueuePriority(),
+            TaskQueue::QueuePriority::kLowPriority);
+  EXPECT_EQ(DeferrableTaskQueue()->GetQueuePriority(),
+            TaskQueue::QueuePriority::kLowPriority);
+  EXPECT_EQ(ThrottleableTaskQueue()->GetQueuePriority(),
+            TaskQueue::QueuePriority::kLowPriority);
+  EXPECT_EQ(PausableTaskQueue()->GetQueuePriority(),
+            TaskQueue::QueuePriority::kLowPriority);
+  EXPECT_EQ(UnpausableTaskQueue()->GetQueuePriority(),
+            TaskQueue::QueuePriority::kLowPriority);
+
+  // Main thread is no longer in loading use case.
+  scheduler_->OnFirstMeaningfulPaint();
+  EXPECT_FALSE(page_scheduler_->IsLoading());
+
+  EXPECT_EQ(LoadingTaskQueue()->GetQueuePriority(),
+            TaskQueue::QueuePriority::kNormalPriority);
+  EXPECT_EQ(LoadingControlTaskQueue()->GetQueuePriority(),
+            TaskQueue::QueuePriority::kHighPriority);
+  EXPECT_EQ(DeferrableTaskQueue()->GetQueuePriority(),
+            TaskQueue::QueuePriority::kNormalPriority);
+  EXPECT_EQ(ThrottleableTaskQueue()->GetQueuePriority(),
+            TaskQueue::QueuePriority::kNormalPriority);
+  EXPECT_EQ(PausableTaskQueue()->GetQueuePriority(),
+            TaskQueue::QueuePriority::kNormalPriority);
+  EXPECT_EQ(UnpausableTaskQueue()->GetQueuePriority(),
+            TaskQueue::QueuePriority::kNormalPriority);
+}
+
 }  // namespace frame_scheduler_impl_unittest
 }  // namespace scheduler
 }  // namespace blink

third_party/blink/renderer/platform/scheduler/main_thread/main_thread_scheduler_impl.cc

@@ -685,6 +685,9 @@ MainThreadSchedulerImpl::SchedulingSettings::SchedulingSettings() {
   best_effort_ad_frame =
       base::FeatureList::IsEnabled(kBestEffortPriorityForAdFrame);
 
+  low_priority_cross_origin =
+      base::FeatureList::IsEnabled(kLowPriorityForCrossOrigin);
+
   use_resource_fetch_priority =
       base::FeatureList::IsEnabled(kUseResourceFetchPriority);
 

third_party/blink/renderer/platform/scheduler/main_thread/main_thread_scheduler_impl.h

@@ -104,6 +104,9 @@ class PLATFORM_EXPORT MainThreadSchedulerImpl
     bool low_priority_ad_frame;
     bool best_effort_ad_frame;
 
+    // Origin type priority experiment (crbug.com/856158).
+    bool low_priority_cross_origin;
+
     // Use resource fetch priority for resource loading tasks
     // (crbug.com/860545).
     bool use_resource_fetch_priority;