LibThreading: Wake up the background worker thread when there's work

The worker thread used for BackgroundAction was going to sleep for
1 second at a time (when there was nothing to do.) This made using
background actions for anything interactive quite unresponsive since
you had to wait up to 1 second before it even started on your task.

We now use a simple Unix pipe to signal the worker thread that a new
work item is available.

This makes Assistant way more responsive when typing. :^)
This commit is contained in:
Andreas Kling 2021-07-04 18:01:01 +02:00
parent d114ba4c4e
commit e8579ed24a
Notes: sideshowbarker 2024-07-18 10:29:44 +09:00
2 changed files with 36 additions and 18 deletions

View file

@ -1,5 +1,6 @@
/*
* Copyright (c) 2019-2020, Sergey Bugaev <bugaevc@serenityos.org>
* Copyright (c) 2021, Andreas Kling <kling@serenityos.org>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
@ -8,24 +9,33 @@
#include <LibThreading/BackgroundAction.h>
#include <LibThreading/Lock.h>
#include <LibThreading/Thread.h>
#include <unistd.h>
static Threading::Lockable<Queue<Function<void()>>>* s_all_actions;
static Threading::Thread* s_background_thread;
static int s_notify_pipe_fds[2];
static intptr_t background_thread_func()
{
while (true) {
Function<void()> work_item;
char buffer[1];
auto nread = read(s_notify_pipe_fds[0], buffer, sizeof(buffer));
if (nread < 0) {
perror("read");
_exit(1);
}
Vector<Function<void()>> work_items;
{
Threading::Locker locker(s_all_actions->lock());
if (!s_all_actions->resource().is_empty())
work_item = s_all_actions->resource().dequeue();
while (!s_all_actions->resource().is_empty()) {
work_items.append(s_all_actions->resource().dequeue());
}
}
if (work_item)
for (auto& work_item : work_items)
work_item();
else
sleep(1);
}
VERIFY_NOT_REACHED();
@ -33,22 +43,32 @@ static intptr_t background_thread_func()
static void init()
{
if (pipe(s_notify_pipe_fds) < 0) {
perror("pipe");
_exit(1);
}
s_all_actions = new Threading::Lockable<Queue<Function<void()>>>();
s_background_thread = &Threading::Thread::construct(background_thread_func).leak_ref();
s_background_thread->set_name("Background thread");
s_background_thread->start();
}
Threading::Lockable<Queue<Function<void()>>>& Threading::BackgroundActionBase::all_actions()
{
if (s_all_actions == nullptr)
init();
return *s_all_actions;
}
Threading::Thread& Threading::BackgroundActionBase::background_thread()
{
if (s_background_thread == nullptr)
init();
return *s_background_thread;
}
void Threading::BackgroundActionBase::enqueue_work(Function<void()> work)
{
if (s_all_actions == nullptr)
init();
Locker locker(s_all_actions->lock());
s_all_actions->resource().enqueue(move(work));
char ch = 'x';
if (write(s_notify_pipe_fds[1], &ch, sizeof(ch)) < 0) {
perror("write");
_exit(1);
}
}

View file

@ -1,5 +1,6 @@
/*
* Copyright (c) 2019-2020, Sergey Bugaev <bugaevc@serenityos.org>
* Copyright (c) 2021, Andreas Kling <kling@serenityos.org>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
@ -13,7 +14,6 @@
#include <LibCore/Event.h>
#include <LibCore/EventLoop.h>
#include <LibCore/Object.h>
#include <LibThreading/Lock.h>
#include <LibThreading/Thread.h>
namespace Threading {
@ -28,7 +28,7 @@ class BackgroundActionBase {
private:
BackgroundActionBase() { }
static Lockable<Queue<Function<void()>>>& all_actions();
static void enqueue_work(Function<void()>);
static Thread& background_thread();
};
@ -63,9 +63,7 @@ private:
, m_action(move(action))
, m_on_complete(move(on_complete))
{
Locker locker(all_actions().lock());
all_actions().resource().enqueue([this] {
enqueue_work([this] {
m_result = m_action(*this);
if (m_on_complete) {
Core::EventLoop::current().post_event(*this, make<Core::DeferredInvocationEvent>([this](auto&) {