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// Copyright 2015 The Chromium Authors
// 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 <algorithm>
#include <memory>
#include <string>
#include <utility>
#include "base/threading/simple_thread.h"
#include "base/trace_event/typed_macros.h"
namespace cc {
SingleThreadTaskGraphRunner::SingleThreadTaskGraphRunner()
: lock_(),
has_ready_to_run_tasks_cv_(&lock_),
has_namespaces_with_finished_running_tasks_cv_(&lock_),
is_idle_cv_(&lock_) {
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_ = std::make_unique<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::ExternalDependencyCompletedForTask(
NamespaceToken token,
scoped_refptr<Task> task) {
base::AutoLock lock(lock_);
if (work_queue_.ExternalDependencyCompletedForTask(token, std::move(task))) {
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::RunTasksUntilIdleForTest() {
base::AutoLock lock(lock_);
while (work_queue_.HasReadyToRunTasks() ||
work_queue_.NumRunningTasks() > 0) {
is_idle_cv_.Wait();
}
}
void SingleThreadTaskGraphRunner::Run() {
base::AutoLock lock(lock_);
while (true) {
if (!RunTaskWithLockAcquired()) {
is_idle_cv_.Signal();
// 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");
// 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::ranges::find_if_not(
ready_to_run_namespaces,
&TaskGraphWorkQueue::TaskNamespace::Vector::empty,
&TaskGraphWorkQueue::ReadyNamespaces::value_type::second);
if (found == ready_to_run_namespaces.cend()) {
return false;
}
const uint16_t category = found->first;
auto prioritized_task = work_queue_.GetNextTaskToRun(category);
{
TRACE_EVENT("toplevel", "cc::SingleThreadTaskGraphRunner::RunTask",
perfetto::TerminatingFlow::Global(
prioritized_task.task->trace_task_id()));
base::AutoUnlock unlock(lock_);
prioritized_task.task->RunOnWorkerThread();
}
auto* task_namespace = prioritized_task.task_namespace.get();
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
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