obs-StreamFX/source/util-threadpool.cpp

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/*
* Modern effects for a modern Streamer
* Copyright (C) 2020 Michael Fabian Dirks
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA
*/
#include "util-threadpool.hpp"
// Most Tasks likely wait for IO, so we can use that time for other tasks.
#define CONCURRENCY_MULTIPLIER 2
util::threadpool::threadpool() : _workers(), _tasks(), _tasks_lock(), _tasks_cv(), _worker_stop(false)
{
size_t concurrency = static_cast<size_t>(std::thread::hardware_concurrency()) * CONCURRENCY_MULTIPLIER;
for (size_t n = 0; n < concurrency; n++) {
_workers.emplace_back(std::bind(&util::threadpool::work, this));
}
}
util::threadpool::~threadpool()
{
_worker_stop = true;
_tasks_cv.notify_all();
for (auto& thread : _workers) {
_tasks_cv.notify_all();
if (thread.joinable())
thread.join();
}
}
void util::threadpool::push(threadpool_function_t fn, std::shared_ptr<void> data)
{
std::unique_lock<std::mutex> lock(_tasks_lock);
_tasks.emplace_back(fn, data);
_tasks_cv.notify_one();
}
void util::threadpool::work()
{
std::pair<threadpool_function_t, std::shared_ptr<void>> work;
while (!_worker_stop) {
// Wait for more work, or immediately continue if there is still work to do.
{
std::unique_lock<std::mutex> lock(_tasks_lock);
if (_tasks.size() == 0)
_tasks_cv.wait(lock, [this]() { return _worker_stop || _tasks.size() > 0; });
if (_tasks.size() == 0)
continue;
work = _tasks.front();
_tasks.pop_front();
}
// Execute work.
if (work.first)
work.first(work.second);
}
}