// Copyright 2014 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/resources/task_graph_runner.h"

#include <vector>

#include "base/memory/scoped_ptr.h"
#include "base/time/time.h"
#include "cc/base/completion_event.h"
#include "cc/debug/lap_timer.h"
#include "testing/gtest/include/gtest/gtest.h"
#include "testing/perf/perf_test.h"

namespace cc {
namespace {

static const int kTimeLimitMillis = 2000;
static const int kWarmupRuns = 5;
static const int kTimeCheckInterval = 10;

class PerfTaskImpl : public Task {
 public:
  typedef std::vector<scoped_refptr<PerfTaskImpl>> Vector;

  PerfTaskImpl() {}

  // Overridden from Task:
  void RunOnWorkerThread() override {}

  void Reset() { did_run_ = false; }

 private:
  ~PerfTaskImpl() override {}

  DISALLOW_COPY_AND_ASSIGN(PerfTaskImpl);
};

class TaskGraphRunnerPerfTest : public testing::Test {
 public:
  TaskGraphRunnerPerfTest()
      : timer_(kWarmupRuns,
               base::TimeDelta::FromMilliseconds(kTimeLimitMillis),
               kTimeCheckInterval) {}

  // Overridden from testing::Test:
  virtual void SetUp() override {
    task_graph_runner_ = make_scoped_ptr(new TaskGraphRunner);
    namespace_token_ = task_graph_runner_->GetNamespaceToken();
  }
  virtual void TearDown() override { task_graph_runner_ = nullptr; }

  void AfterTest(const std::string& test_name) {
    // Format matches chrome/test/perf/perf_test.h:PrintResult
    printf(
        "*RESULT %s: %.2f runs/s\n", test_name.c_str(), timer_.LapsPerSecond());
  }

  void RunBuildTaskGraphTest(const std::string& test_name,
                             int num_top_level_tasks,
                             int num_tasks,
                             int num_leaf_tasks) {
    PerfTaskImpl::Vector top_level_tasks;
    PerfTaskImpl::Vector tasks;
    PerfTaskImpl::Vector leaf_tasks;
    CreateTasks(num_top_level_tasks, &top_level_tasks);
    CreateTasks(num_tasks, &tasks);
    CreateTasks(num_leaf_tasks, &leaf_tasks);

    // Avoid unnecessary heap allocations by reusing the same graph.
    TaskGraph graph;

    timer_.Reset();
    do {
      graph.Reset();
      BuildTaskGraph(top_level_tasks, tasks, leaf_tasks, &graph);
      timer_.NextLap();
    } while (!timer_.HasTimeLimitExpired());

    perf_test::PrintResult("build_task_graph",
                           TestModifierString(),
                           test_name,
                           timer_.LapsPerSecond(),
                           "runs/s",
                           true);
  }

  void RunScheduleTasksTest(const std::string& test_name,
                            int num_top_level_tasks,
                            int num_tasks,
                            int num_leaf_tasks) {
    PerfTaskImpl::Vector top_level_tasks;
    PerfTaskImpl::Vector tasks;
    PerfTaskImpl::Vector leaf_tasks;
    CreateTasks(num_top_level_tasks, &top_level_tasks);
    CreateTasks(num_tasks, &tasks);
    CreateTasks(num_leaf_tasks, &leaf_tasks);

    // Avoid unnecessary heap allocations by reusing the same graph and
    // completed tasks vector.
    TaskGraph graph;
    Task::Vector completed_tasks;

    timer_.Reset();
    do {
      graph.Reset();
      BuildTaskGraph(top_level_tasks, tasks, leaf_tasks, &graph);
      task_graph_runner_->ScheduleTasks(namespace_token_, &graph);
      // Shouldn't be any tasks to collect as we reschedule the same set
      // of tasks.
      DCHECK_EQ(0u, CollectCompletedTasks(&completed_tasks));
      timer_.NextLap();
    } while (!timer_.HasTimeLimitExpired());

    TaskGraph empty;
    task_graph_runner_->ScheduleTasks(namespace_token_, &empty);
    CollectCompletedTasks(&completed_tasks);

    perf_test::PrintResult("schedule_tasks",
                           TestModifierString(),
                           test_name,
                           timer_.LapsPerSecond(),
                           "runs/s",
                           true);
  }

  void RunScheduleAlternateTasksTest(const std::string& test_name,
                                     int num_top_level_tasks,
                                     int num_tasks,
                                     int num_leaf_tasks) {
    const size_t kNumVersions = 2;
    PerfTaskImpl::Vector top_level_tasks[kNumVersions];
    PerfTaskImpl::Vector tasks[kNumVersions];
    PerfTaskImpl::Vector leaf_tasks[kNumVersions];
    for (size_t i = 0; i < kNumVersions; ++i) {
      CreateTasks(num_top_level_tasks, &top_level_tasks[i]);
      CreateTasks(num_tasks, &tasks[i]);
      CreateTasks(num_leaf_tasks, &leaf_tasks[i]);
    }

    // Avoid unnecessary heap allocations by reusing the same graph and
    // completed tasks vector.
    TaskGraph graph;
    Task::Vector completed_tasks;

    size_t count = 0;
    timer_.Reset();
    do {
      graph.Reset();
      BuildTaskGraph(top_level_tasks[count % kNumVersions],
                     tasks[count % kNumVersions],
                     leaf_tasks[count % kNumVersions],
                     &graph);
      task_graph_runner_->ScheduleTasks(namespace_token_, &graph);
      CollectCompletedTasks(&completed_tasks);
      completed_tasks.clear();
      ++count;
      timer_.NextLap();
    } while (!timer_.HasTimeLimitExpired());

    TaskGraph empty;
    task_graph_runner_->ScheduleTasks(namespace_token_, &empty);
    CollectCompletedTasks(&completed_tasks);

    perf_test::PrintResult("schedule_alternate_tasks",
                           TestModifierString(),
                           test_name,
                           timer_.LapsPerSecond(),
                           "runs/s",
                           true);
  }

  void RunScheduleAndExecuteTasksTest(const std::string& test_name,
                                      int num_top_level_tasks,
                                      int num_tasks,
                                      int num_leaf_tasks) {
    PerfTaskImpl::Vector top_level_tasks;
    PerfTaskImpl::Vector tasks;
    PerfTaskImpl::Vector leaf_tasks;
    CreateTasks(num_top_level_tasks, &top_level_tasks);
    CreateTasks(num_tasks, &tasks);
    CreateTasks(num_leaf_tasks, &leaf_tasks);

    // Avoid unnecessary heap allocations by reusing the same graph and
    // completed tasks vector.
    TaskGraph graph;
    Task::Vector completed_tasks;

    timer_.Reset();
    do {
      graph.Reset();
      BuildTaskGraph(top_level_tasks, tasks, leaf_tasks, &graph);
      task_graph_runner_->ScheduleTasks(namespace_token_, &graph);
      task_graph_runner_->RunUntilIdle();
      CollectCompletedTasks(&completed_tasks);
      completed_tasks.clear();
      ResetTasks(&top_level_tasks);
      ResetTasks(&tasks);
      ResetTasks(&leaf_tasks);
      timer_.NextLap();
    } while (!timer_.HasTimeLimitExpired());

    perf_test::PrintResult("execute_tasks",
                           TestModifierString(),
                           test_name,
                           timer_.LapsPerSecond(),
                           "runs/s",
                           true);
  }

 private:
  static std::string TestModifierString() {
    return std::string("_task_graph_runner");
  }

  void CreateTasks(int num_tasks, PerfTaskImpl::Vector* tasks) {
    for (int i = 0; i < num_tasks; ++i)
      tasks->push_back(make_scoped_refptr(new PerfTaskImpl));
  }

  void ResetTasks(PerfTaskImpl::Vector* tasks) {
    for (PerfTaskImpl::Vector::iterator it = tasks->begin(); it != tasks->end();
         ++it) {
      PerfTaskImpl* task = it->get();
      task->Reset();
    }
  }

  void BuildTaskGraph(const PerfTaskImpl::Vector& top_level_tasks,
                      const PerfTaskImpl::Vector& tasks,
                      const PerfTaskImpl::Vector& leaf_tasks,
                      TaskGraph* graph) {
    DCHECK(graph->nodes.empty());
    DCHECK(graph->edges.empty());

    for (PerfTaskImpl::Vector::const_iterator it = leaf_tasks.begin();
         it != leaf_tasks.end();
         ++it) {
      graph->nodes.push_back(TaskGraph::Node(it->get(), 0u, 0u));
    }

    for (PerfTaskImpl::Vector::const_iterator it = tasks.begin();
         it != tasks.end();
         ++it) {
      graph->nodes.push_back(TaskGraph::Node(it->get(), 0u, leaf_tasks.size()));

      for (PerfTaskImpl::Vector::const_iterator leaf_it = leaf_tasks.begin();
           leaf_it != leaf_tasks.end();
           ++leaf_it) {
        graph->edges.push_back(TaskGraph::Edge(leaf_it->get(), it->get()));
      }

      for (PerfTaskImpl::Vector::const_iterator top_level_it =
               top_level_tasks.begin();
           top_level_it != top_level_tasks.end();
           ++top_level_it) {
        graph->edges.push_back(TaskGraph::Edge(it->get(), top_level_it->get()));
      }
    }

    for (PerfTaskImpl::Vector::const_iterator it = top_level_tasks.begin();
         it != top_level_tasks.end();
         ++it) {
      graph->nodes.push_back(TaskGraph::Node(it->get(), 0u, tasks.size()));
    }
  }

  size_t CollectCompletedTasks(Task::Vector* completed_tasks) {
    DCHECK(completed_tasks->empty());
    task_graph_runner_->CollectCompletedTasks(namespace_token_,
                                              completed_tasks);
    return completed_tasks->size();
  }

  scoped_ptr<TaskGraphRunner> task_graph_runner_;
  NamespaceToken namespace_token_;
  LapTimer timer_;
};

TEST_F(TaskGraphRunnerPerfTest, BuildTaskGraph) {
  RunBuildTaskGraphTest("0_1_0", 0, 1, 0);
  RunBuildTaskGraphTest("0_32_0", 0, 32, 0);
  RunBuildTaskGraphTest("2_1_0", 2, 1, 0);
  RunBuildTaskGraphTest("2_32_0", 2, 32, 0);
  RunBuildTaskGraphTest("2_1_1", 2, 1, 1);
  RunBuildTaskGraphTest("2_32_1", 2, 32, 1);
}

TEST_F(TaskGraphRunnerPerfTest, ScheduleTasks) {
  RunScheduleTasksTest("0_1_0", 0, 1, 0);
  RunScheduleTasksTest("0_32_0", 0, 32, 0);
  RunScheduleTasksTest("2_1_0", 2, 1, 0);
  RunScheduleTasksTest("2_32_0", 2, 32, 0);
  RunScheduleTasksTest("2_1_1", 2, 1, 1);
  RunScheduleTasksTest("2_32_1", 2, 32, 1);
}

TEST_F(TaskGraphRunnerPerfTest, ScheduleAlternateTasks) {
  RunScheduleAlternateTasksTest("0_1_0", 0, 1, 0);
  RunScheduleAlternateTasksTest("0_32_0", 0, 32, 0);
  RunScheduleAlternateTasksTest("2_1_0", 2, 1, 0);
  RunScheduleAlternateTasksTest("2_32_0", 2, 32, 0);
  RunScheduleAlternateTasksTest("2_1_1", 2, 1, 1);
  RunScheduleAlternateTasksTest("2_32_1", 2, 32, 1);
}

TEST_F(TaskGraphRunnerPerfTest, ScheduleAndExecuteTasks) {
  RunScheduleAndExecuteTasksTest("0_1_0", 0, 1, 0);
  RunScheduleAndExecuteTasksTest("0_32_0", 0, 32, 0);
  RunScheduleAndExecuteTasksTest("2_1_0", 2, 1, 0);
  RunScheduleAndExecuteTasksTest("2_32_0", 2, 32, 0);
  RunScheduleAndExecuteTasksTest("2_1_1", 2, 1, 1);
  RunScheduleAndExecuteTasksTest("2_32_1", 2, 32, 1);
}

}  // namespace
}  // namespace cc