blob: 67e4ab32d819c4170731663157c11579da6bfb38 [file] [log] [blame]
// 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/raster/single_thread_task_graph_runner.h"
#include <stdint.h>
#include <string>
#include "base/threading/simple_thread.h"
#include "base/trace_event/trace_event.h"
namespace cc {
SingleThreadTaskGraphRunner::SingleThreadTaskGraphRunner()
: lock_(),
has_ready_to_run_tasks_cv_(&lock_),
has_namespaces_with_finished_running_tasks_cv_(&lock_),
shutdown_(false) {
has_ready_to_run_tasks_cv_.declare_only_used_while_idle();
}
SingleThreadTaskGraphRunner::~SingleThreadTaskGraphRunner() = default;
void SingleThreadTaskGraphRunner::Start(
const std::string& thread_name,
const base::SimpleThread::Options& thread_options) {
thread_.reset(
new base::DelegateSimpleThread(this, thread_name, thread_options));
thread_->StartAsync();
}
void SingleThreadTaskGraphRunner::Shutdown() {
{
base::AutoLock lock(lock_);
DCHECK(!work_queue_.HasReadyToRunTasks());
DCHECK(!work_queue_.HasAnyNamespaces());
DCHECK(!shutdown_);
shutdown_ = true;
// Wake up the worker so it knows it should exit.
has_ready_to_run_tasks_cv_.Signal();
}
thread_->Join();
}
NamespaceToken SingleThreadTaskGraphRunner::GenerateNamespaceToken() {
base::AutoLock lock(lock_);
return work_queue_.GenerateNamespaceToken();
}
void SingleThreadTaskGraphRunner::ScheduleTasks(NamespaceToken token,
TaskGraph* graph) {
TRACE_EVENT2("cc", "SingleThreadTaskGraphRunner::ScheduleTasks", "num_nodes",
graph->nodes.size(), "num_edges", graph->edges.size());
DCHECK(token.IsValid());
DCHECK(!TaskGraphWorkQueue::DependencyMismatch(graph));
{
base::AutoLock lock(lock_);
DCHECK(!shutdown_);
work_queue_.ScheduleTasks(token, graph);
// If there is more work available, wake up the worker thread.
if (work_queue_.HasReadyToRunTasks())
has_ready_to_run_tasks_cv_.Signal();
}
}
void SingleThreadTaskGraphRunner::WaitForTasksToFinishRunning(
NamespaceToken token) {
TRACE_EVENT0("cc",
"SingleThreadTaskGraphRunner::WaitForTasksToFinishRunning");
DCHECK(token.IsValid());
{
base::AutoLock lock(lock_);
auto* task_namespace = work_queue_.GetNamespaceForToken(token);
if (!task_namespace)
return;
while (!work_queue_.HasFinishedRunningTasksInNamespace(task_namespace))
has_namespaces_with_finished_running_tasks_cv_.Wait();
// There may be other namespaces that have finished running tasks, so wake
// up another origin thread.
has_namespaces_with_finished_running_tasks_cv_.Signal();
}
}
void SingleThreadTaskGraphRunner::CollectCompletedTasks(
NamespaceToken token,
Task::Vector* completed_tasks) {
TRACE_EVENT0("cc", "SingleThreadTaskGraphRunner::CollectCompletedTasks");
DCHECK(token.IsValid());
{
base::AutoLock lock(lock_);
work_queue_.CollectCompletedTasks(token, completed_tasks);
}
}
void SingleThreadTaskGraphRunner::Run() {
base::AutoLock lock(lock_);
while (true) {
if (!RunTaskWithLockAcquired()) {
// Exit when shutdown is set and no more tasks are pending.
if (shutdown_)
break;
// Wait for more tasks.
has_ready_to_run_tasks_cv_.Wait();
continue;
}
}
}
bool SingleThreadTaskGraphRunner::RunTaskWithLockAcquired() {
TRACE_EVENT0("toplevel",
"SingleThreadTaskGraphRunner::RunTaskWithLockAcquired");
lock_.AssertAcquired();
// Find the first category with any tasks to run. This task graph runner
// treats categories as an additional priority.
const auto& ready_to_run_namespaces = work_queue_.ready_to_run_namespaces();
auto found = std::find_if(
ready_to_run_namespaces.cbegin(), ready_to_run_namespaces.cend(),
[](const std::pair<const uint16_t,
TaskGraphWorkQueue::TaskNamespace::Vector>& pair) {
return !pair.second.empty();
});
if (found == ready_to_run_namespaces.cend()) {
return false;
}
const uint16_t category = found->first;
auto prioritized_task = work_queue_.GetNextTaskToRun(category);
{
base::AutoUnlock unlock(lock_);
prioritized_task.task->RunOnWorkerThread();
}
auto* task_namespace = prioritized_task.task_namespace;
work_queue_.CompleteTask(std::move(prioritized_task));
// If namespace has finished running all tasks, wake up origin thread.
if (work_queue_.HasFinishedRunningTasksInNamespace(task_namespace))
has_namespaces_with_finished_running_tasks_cv_.Signal();
return true;
}
} // namespace cc