cc: Remove cheapness estimator usage from tile manager.

cc/base/worker_pool.cc

 // Copyright 2013 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/base/worker_pool.h"
 
+#if defined(OS_ANDROID)
+// TODO(epenner): Move thread priorities to base. (crbug.com/170549)
+#include <sys/resource.h>
+#endif
+
 #include <algorithm>
 
 #include "base/bind.h"
 #include "base/debug/trace_event.h"
 #include "base/stringprintf.h"
 #include "base/synchronization/condition_variable.h"
 #include "base/threading/simple_thread.h"
 
-#if defined(OS_ANDROID)
-// TODO(epenner): Move thread priorities to base. (crbug.com/170549)
-#include <sys/resource.h>
-#endif
-
 namespace cc {
 
 namespace {
 
 class WorkerPoolTaskImpl : public internal::WorkerPoolTask {
  public:
   WorkerPoolTaskImpl(const WorkerPool::Callback& task,
                      const base::Closure& reply)
       : internal::WorkerPoolTask(reply),
         task_(task) {}
 
-  virtual bool IsCheap() OVERRIDE { return false; }
-
-  virtual void Run() OVERRIDE {
-    task_.Run();
-  }
-
   virtual void RunOnThread(unsigned thread_index) OVERRIDE {
     task_.Run();
   }
 
  private:
   WorkerPool::Callback task_;
 };
 
 }  // namespace
 
@@ skipping 11 matching lines @@
 
 }  // namespace internal
 
 // Internal to the worker pool. Any data or logic that needs to be
 // shared between threads lives in this class. All members are guarded
 // by |lock_|.
 class WorkerPool::Inner : public base::DelegateSimpleThread::Delegate {
  public:
   Inner(WorkerPool* worker_pool,
         size_t num_threads,
-        const std::string& thread_name_prefix,
-        bool need_on_task_completed_callback);
+        const std::string& thread_name_prefix);
   virtual ~Inner();
 
   void Shutdown();
 
-  void PostTask(scoped_ptr<internal::WorkerPoolTask> task, bool signal_workers);
+  void PostTask(scoped_ptr<internal::WorkerPoolTask> task);
 
   // Appends all completed tasks to worker pool's completed tasks queue
   // and returns true if idle.
   bool CollectCompletedTasks();
 
-  // Runs cheap tasks on caller thread until |time_limit| is reached
-  // and returns true if idle.
-  bool RunCheapTasksUntilTimeLimit(base::TimeTicks time_limit);
-
  private:
   // Appends all completed tasks to |completed_tasks|. Lock must
   // already be acquired before calling this function.
   bool AppendCompletedTasksWithLockAcquired(
       ScopedPtrDeque<internal::WorkerPoolTask>* completed_tasks);
 
-  // Schedule a OnTaskCompletedOnOriginThread callback if not already
-  // pending. Lock must already be acquired before calling this function.
-  void ScheduleOnTaskCompletedWithLockAcquired();
-  void OnTaskCompletedOnOriginThread();
-
   // Schedule an OnIdleOnOriginThread callback if not already pending.
   // Lock must already be acquired before calling this function.
   void ScheduleOnIdleWithLockAcquired();
   void OnIdleOnOriginThread();
 
   // Overridden from base::DelegateSimpleThread:
   virtual void Run() OVERRIDE;
 
   // Pointer to worker pool. Can only be used on origin thread.
   // Not guarded by |lock_|.
   WorkerPool* worker_pool_on_origin_thread_;
 
   // This lock protects all members of this class except
   // |worker_pool_on_origin_thread_|. Do not read or modify anything
   // without holding this lock. Do not block while holding this lock.
   mutable base::Lock lock_;
 
   // Condition variable that is waited on by worker threads until new
   // tasks are posted or shutdown starts.
   base::ConditionVariable has_pending_tasks_cv_;
 
   // Target message loop used for posting callbacks.
   scoped_refptr<base::MessageLoopProxy> origin_loop_;
 
   base::WeakPtrFactory<Inner> weak_ptr_factory_;
 
-  // Set to true when worker pool requires a callback for each
-  // completed task.
-  bool need_on_task_completed_callback_;
-
-  const base::Closure on_task_completed_callback_;
-  // Set when a OnTaskCompletedOnOriginThread() callback is pending.
-  bool on_task_completed_pending_;
-
   const base::Closure on_idle_callback_;
   // Set when a OnIdleOnOriginThread() callback is pending.
   bool on_idle_pending_;
 
   // Provides each running thread loop with a unique index. First thread
   // loop index is 0.
   unsigned next_thread_index_;
 
   // Number of tasks currently running.
   unsigned running_task_count_;
 
   // Set during shutdown. Tells workers to exit when no more tasks
   // are pending.
   bool shutdown_;
 
   typedef ScopedPtrDeque<internal::WorkerPoolTask> TaskDeque;
   TaskDeque pending_tasks_;
   TaskDeque completed_tasks_;
 
   ScopedPtrDeque<base::DelegateSimpleThread> workers_;
 
   DISALLOW_COPY_AND_ASSIGN(Inner);
 };
 
 WorkerPool::Inner::Inner(WorkerPool* worker_pool,
                          size_t num_threads,
-                         const std::string& thread_name_prefix,
-                         bool need_on_task_completed_callback)
+                         const std::string& thread_name_prefix)
     : worker_pool_on_origin_thread_(worker_pool),
       lock_(),
       has_pending_tasks_cv_(&lock_),
       origin_loop_(base::MessageLoopProxy::current()),
       weak_ptr_factory_(this),
-      need_on_task_completed_callback_(need_on_task_completed_callback),
-      on_task_completed_callback_(
-          base::Bind(&WorkerPool::Inner::OnTaskCompletedOnOriginThread,
-                     weak_ptr_factory_.GetWeakPtr())),
-      on_task_completed_pending_(false),
       on_idle_callback_(base::Bind(&WorkerPool::Inner::OnIdleOnOriginThread,
                                    weak_ptr_factory_.GetWeakPtr())),
       on_idle_pending_(false),
       next_thread_index_(0),
       running_task_count_(0),
       shutdown_(false) {
   base::AutoLock lock(lock_);
 
   while (workers_.size() < num_threads) {
     scoped_ptr<base::DelegateSimpleThread> worker = make_scoped_ptr(
         new base::DelegateSimpleThread(
           this,
           thread_name_prefix +
           base::StringPrintf(
-              "Worker%lu",
-              static_cast<unsigned long>(workers_.size() + 1)).c_str()));
+              "Worker%u",
+              static_cast<unsigned>(workers_.size() + 1)).c_str()));

[vmpstr, 2013/04/26 22:51:35]

nit: is the static_cast required here now?

[reveman, 2013/04/26 23:09:42]

Done.

     worker->Start();
     workers_.push_back(worker.Pass());
   }
 }
 
 WorkerPool::Inner::~Inner() {
   base::AutoLock lock(lock_);
 
   DCHECK(shutdown_);
 
@@ skipping 16 matching lines @@
     // to exit as each will wake up another worker before exiting.
     has_pending_tasks_cv_.Signal();
   }
 
   while (workers_.size()) {
     scoped_ptr<base::DelegateSimpleThread> worker = workers_.take_front();
     worker->Join();
   }
 }
 
-void WorkerPool::Inner::PostTask(scoped_ptr<internal::WorkerPoolTask> task,
-                                 bool signal_workers) {
+void WorkerPool::Inner::PostTask(scoped_ptr<internal::WorkerPoolTask> task) {
   base::AutoLock lock(lock_);
 
   pending_tasks_.push_back(task.Pass());
 
   // There is more work available, so wake up worker thread.
-  if (signal_workers)
-    has_pending_tasks_cv_.Signal();
+  has_pending_tasks_cv_.Signal();
 }
 
 bool WorkerPool::Inner::CollectCompletedTasks() {
   base::AutoLock lock(lock_);
 
   return AppendCompletedTasksWithLockAcquired(
       &worker_pool_on_origin_thread_->completed_tasks_);
 }
 
-bool WorkerPool::Inner::RunCheapTasksUntilTimeLimit(
-    base::TimeTicks time_limit) {
-  base::AutoLock lock(lock_);
-
-  while (base::TimeTicks::Now() < time_limit) {
-    scoped_ptr<internal::WorkerPoolTask> task;
-
-    // Find next cheap task.
-    for (TaskDeque::iterator iter = pending_tasks_.begin();
-         iter != pending_tasks_.end(); ++iter) {
-      if ((*iter)->IsCheap()) {
-        task = pending_tasks_.take(iter);
-        break;
-      }
-    }
-
-    if (!task) {
-      // Schedule an idle callback if requested and not pending.
-      if (!running_task_count_ && pending_tasks_.empty())
-        ScheduleOnIdleWithLockAcquired();
-
-      // Exit when no more cheap tasks are pending.
-      break;
-    }
-
-    // Increment |running_task_count_| before starting to run task.
-    running_task_count_++;
-
-    {
-      base::AutoUnlock unlock(lock_);
-
-      task->Run();
-
-      // Append tasks directly to worker pool's completed tasks queue.
-      worker_pool_on_origin_thread_->completed_tasks_.push_back(task.Pass());
-      if (need_on_task_completed_callback_)
-        worker_pool_on_origin_thread_->OnTaskCompleted();
-    }
-
-    // Decrement |running_task_count_| now that we are done running task.
-    running_task_count_--;
-  }
-
-  if (!pending_tasks_.empty())
-    has_pending_tasks_cv_.Signal();
-
-  // Append any other completed tasks before releasing lock.
-  return AppendCompletedTasksWithLockAcquired(
-      &worker_pool_on_origin_thread_->completed_tasks_);
-}
-
 bool WorkerPool::Inner::AppendCompletedTasksWithLockAcquired(
     ScopedPtrDeque<internal::WorkerPoolTask>* completed_tasks) {
   lock_.AssertAcquired();
 
   while (completed_tasks_.size())
     completed_tasks->push_back(completed_tasks_.take_front().Pass());
 
   return !running_task_count_ && pending_tasks_.empty();
 }
 
-void WorkerPool::Inner::ScheduleOnTaskCompletedWithLockAcquired() {
-  lock_.AssertAcquired();
-
-  if (on_task_completed_pending_ || !need_on_task_completed_callback_)
-    return;
-  origin_loop_->PostTask(FROM_HERE, on_task_completed_callback_);
-  on_task_completed_pending_ = true;
-}
-
-void WorkerPool::Inner::OnTaskCompletedOnOriginThread() {
-  {
-    base::AutoLock lock(lock_);
-
-    DCHECK(on_task_completed_pending_);
-    on_task_completed_pending_ = false;
-
-    AppendCompletedTasksWithLockAcquired(
-        &worker_pool_on_origin_thread_->completed_tasks_);
-  }
-
-  worker_pool_on_origin_thread_->OnTaskCompleted();
-}
-
 void WorkerPool::Inner::ScheduleOnIdleWithLockAcquired() {
   lock_.AssertAcquired();
 
   if (on_idle_pending_)
     return;
   origin_loop_->PostTask(FROM_HERE, on_idle_callback_);
   on_idle_pending_ = true;
 }
 
 void WorkerPool::Inner::OnIdleOnOriginThread() {
@@ skipping 13 matching lines @@
 
   worker_pool_on_origin_thread_->OnIdle();
 }
 
 void WorkerPool::Inner::Run() {
 #if defined(OS_ANDROID)
   // TODO(epenner): Move thread priorities to base. (crbug.com/170549)
   int nice_value = 10;  // Idle priority.
   setpriority(PRIO_PROCESS, base::PlatformThread::CurrentId(), nice_value);
 #endif
-  {
-    base::AutoLock lock(lock_);
 
-    // Get a unique thread index.
-    int thread_index = next_thread_index_++;
+  base::AutoLock lock(lock_);
 
-    while (true) {
-      if (pending_tasks_.empty()) {
-        // Exit when shutdown is set and no more tasks are pending.
-        if (shutdown_)
-          break;
+  // Get a unique thread index.
+  int thread_index = next_thread_index_++;
 
-        // Schedule an idle callback if requested and not pending.
-        if (!running_task_count_)
-          ScheduleOnIdleWithLockAcquired();
+  while (true) {
+    if (pending_tasks_.empty()) {
+      // Exit when shutdown is set and no more tasks are pending.
+      if (shutdown_)
+        break;
 
-        // Wait for new pending tasks.
-        has_pending_tasks_cv_.Wait();
-        continue;
-      }
+      // Schedule an idle callback if requested and not pending.
+      if (!running_task_count_)
+        ScheduleOnIdleWithLockAcquired();
 
-      // Get next task.
-      scoped_ptr<internal::WorkerPoolTask> task = pending_tasks_.take_front();
-
-      // Increment |running_task_count_| before starting to run task.
-      running_task_count_++;
-
-      // There may be more work available, so wake up another
-      // worker thread.
-      has_pending_tasks_cv_.Signal();
-
-      {
-        base::AutoUnlock unlock(lock_);
-
-        task->RunOnThread(thread_index);
-      }
-
-      completed_tasks_.push_back(task.Pass());
-
-      // Decrement |running_task_count_| now that we are done running task.
-      running_task_count_--;
-
-      // Schedule a task completed callback if requested and not pending.
-      ScheduleOnTaskCompletedWithLockAcquired();
+      // Wait for new pending tasks.
+      has_pending_tasks_cv_.Wait();
+      continue;
     }
 
-    // We noticed we should exit. Wake up the next worker so it knows it should
-    // exit as well (because the Shutdown() code only signals once).
+    // Get next task.
+    scoped_ptr<internal::WorkerPoolTask> task = pending_tasks_.take_front();
+
+    // Increment |running_task_count_| before starting to run task.
+    running_task_count_++;
+
+    // There may be more work available, so wake up another
+    // worker thread.
     has_pending_tasks_cv_.Signal();
+
+    {
+      base::AutoUnlock unlock(lock_);
+
+      task->RunOnThread(thread_index);
+    }
+
+    completed_tasks_.push_back(task.Pass());
+
+    // Decrement |running_task_count_| now that we are done running task.
+    running_task_count_--;
   }
+
+  // We noticed we should exit. Wake up the next worker so it knows it should
+  // exit as well (because the Shutdown() code only signals once).
+  has_pending_tasks_cv_.Signal();
 }
 
 WorkerPool::WorkerPool(WorkerPoolClient* client,
                        size_t num_threads,
                        base::TimeDelta check_for_completed_tasks_delay,
                        const std::string& thread_name_prefix)
     : client_(client),
       origin_loop_(base::MessageLoopProxy::current()),
       weak_ptr_factory_(this),
       check_for_completed_tasks_delay_(check_for_completed_tasks_delay),
       check_for_completed_tasks_pending_(false),
-      run_cheap_tasks_callback_(
-          base::Bind(&WorkerPool::RunCheapTasks,
-                     weak_ptr_factory_.GetWeakPtr())),
-      run_cheap_tasks_pending_(false),
-      inner_(make_scoped_ptr(
-                 new Inner(
-                     this,
-                     num_threads,
-                     thread_name_prefix,
-                     // Request OnTaskCompleted() callback when check
-                     // for completed tasks delay is 0.
-                     check_for_completed_tasks_delay == base::TimeDelta()))) {
+      inner_(make_scoped_ptr(new Inner(this,
+                                       num_threads,
+                                       thread_name_prefix))) {
 }
 
 WorkerPool::~WorkerPool() {
   Shutdown();
 
   // Cancel all pending callbacks.
   weak_ptr_factory_.InvalidateWeakPtrs();
 
   DCHECK_EQ(0u, completed_tasks_.size());
 }
 
 void WorkerPool::Shutdown() {
   inner_->Shutdown();
   DispatchCompletionCallbacks();
 }
 
 void WorkerPool::PostTaskAndReply(
     const Callback& task, const base::Closure& reply) {
   PostTask(make_scoped_ptr(new WorkerPoolTaskImpl(
                                task,
                                reply)).PassAs<internal::WorkerPoolTask>());
 }
 
-void WorkerPool::SetRunCheapTasksTimeLimit(
-    base::TimeTicks run_cheap_tasks_time_limit) {
-  run_cheap_tasks_time_limit_ = run_cheap_tasks_time_limit;
-  ScheduleRunCheapTasks();
-}
-
 void WorkerPool::OnIdle() {
   TRACE_EVENT0("cc", "WorkerPool::OnIdle");
 
   DispatchCompletionCallbacks();
 }
 
-void WorkerPool::OnTaskCompleted() {
-  TRACE_EVENT0("cc", "WorkerPool::OnTaskCompleted");
-
-  DispatchCompletionCallbacks();
-}
-
 void WorkerPool::ScheduleCheckForCompletedTasks() {
-  if (check_for_completed_tasks_pending_ ||
-      check_for_completed_tasks_delay_ == base::TimeDelta())
+  if (check_for_completed_tasks_pending_)
     return;
-  check_for_completed_tasks_callback_.Reset(
-    base::Bind(&WorkerPool::CheckForCompletedTasks,
-               weak_ptr_factory_.GetWeakPtr()));
-  check_for_completed_tasks_time_ = base::TimeTicks::Now() +
-      check_for_completed_tasks_delay_;
   origin_loop_->PostDelayedTask(
       FROM_HERE,
-      check_for_completed_tasks_callback_.callback(),
+      base::Bind(&WorkerPool::CheckForCompletedTasks,
+                 weak_ptr_factory_.GetWeakPtr()),
       check_for_completed_tasks_delay_);
   check_for_completed_tasks_pending_ = true;
 }
 
 void WorkerPool::CheckForCompletedTasks() {
   TRACE_EVENT0("cc", "WorkerPool::CheckForCompletedTasks");
   DCHECK(check_for_completed_tasks_pending_);
   check_for_completed_tasks_pending_ = false;
 
   // Schedule another check for completed tasks if not idle.
   if (!inner_->CollectCompletedTasks())
     ScheduleCheckForCompletedTasks();
 
   DispatchCompletionCallbacks();
 }
 
-void WorkerPool::CancelCheckForCompletedTasks() {
-  if (!check_for_completed_tasks_pending_)
-    return;
-
-  check_for_completed_tasks_callback_.Cancel();
-  check_for_completed_tasks_pending_ = false;
-}
-
 void WorkerPool::DispatchCompletionCallbacks() {
   TRACE_EVENT0("cc", "WorkerPool::DispatchCompletionCallbacks");
 
   if (completed_tasks_.empty())
     return;
 
   while (completed_tasks_.size()) {
     scoped_ptr<internal::WorkerPoolTask> task = completed_tasks_.take_front();
     task->DidComplete();
   }
 
   client_->DidFinishDispatchingWorkerPoolCompletionCallbacks();
 }
 
 void WorkerPool::PostTask(scoped_ptr<internal::WorkerPoolTask> task) {
-  bool signal_workers = true;
-  if (task->IsCheap()) {
-    // To make cheap tasks more likely to run on the origin thread, don't wake
-    // workers when posting them.
-    signal_workers = false;
-    ScheduleRunCheapTasks();
-  }
-
   // Schedule check for completed tasks if not pending.
   ScheduleCheckForCompletedTasks();
 
-  inner_->PostTask(task.Pass(), signal_workers);
-}
-
-void WorkerPool::ScheduleRunCheapTasks() {
-  if (run_cheap_tasks_pending_)
-    return;
-  origin_loop_->PostTask(FROM_HERE, run_cheap_tasks_callback_);
-  run_cheap_tasks_pending_ = true;
-}
-
-void WorkerPool::RunCheapTasks() {
-  TRACE_EVENT0("cc", "WorkerPool::RunCheapTasks");
-  DCHECK(run_cheap_tasks_pending_);
-  run_cheap_tasks_pending_ = false;
-
-  while (true) {
-    base::TimeTicks time_limit = run_cheap_tasks_time_limit_;
-
-    if (!check_for_completed_tasks_time_.is_null())
-      time_limit = std::min(time_limit, check_for_completed_tasks_time_);
-
-    bool is_idle = inner_->RunCheapTasksUntilTimeLimit(time_limit);
-
-    base::TimeTicks now = base::TimeTicks::Now();
-    if (now >= run_cheap_tasks_time_limit_) {
-      TRACE_EVENT_INSTANT0("cc", "WorkerPool::RunCheapTasks out of time",
-                           TRACE_EVENT_SCOPE_THREAD);
-      break;
-    }
-
-    // We must be out of cheap tasks if this happens.
-    if (!check_for_completed_tasks_pending_ ||
-        now < check_for_completed_tasks_time_)
-      break;
-
-    TRACE_EVENT_INSTANT0("cc", "WorkerPool::RunCheapTasks check time",
-                         TRACE_EVENT_SCOPE_THREAD);
-    CancelCheckForCompletedTasks();
-    DispatchCompletionCallbacks();
-    // Schedule another check for completed tasks if not idle.
-    if (!is_idle)
-      ScheduleCheckForCompletedTasks();
-  }
+  inner_->PostTask(task.Pass());
 }
 
 }  // namespace cc