monero/src/common/threadpool.cpp

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// Copyright (c) 2017, The Monero Project
//
// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without modification, are
// permitted provided that the following conditions are met:
//
// 1. Redistributions of source code must retain the above copyright notice, this list of
// conditions and the following disclaimer.
//
// 2. Redistributions in binary form must reproduce the above copyright notice, this list
// of conditions and the following disclaimer in the documentation and/or other
// materials provided with the distribution.
//
// 3. Neither the name of the copyright holder nor the names of its contributors may be
// used to endorse or promote products derived from this software without specific
// prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY
// EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
// MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
// THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
// PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
// INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
// STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF
// THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
#include "common/threadpool.h"
#include <cassert>
#include <limits>
#include <stdexcept>
#include "cryptonote_config.h"
#include "common/util.h"
namespace tools
{
threadpool::threadpool() : running(true), active(0) {
boost::thread::attributes attrs;
attrs.set_stack_size(THREAD_STACK_SIZE);
max = tools::get_max_concurrency() * 2;
size_t i = max;
while(i--) {
threads.push_back(boost::thread(attrs, boost::bind(&threadpool::run, this)));
}
}
threadpool::~threadpool() {
{
const boost::unique_lock<boost::mutex> lock(mutex);
running = false;
has_work.notify_all();
}
for (size_t i = 0; i<threads.size(); i++) {
threads[i].join();
}
}
void threadpool::submit(waiter *obj, std::function<void()> f) {
entry e = {obj, f};
boost::unique_lock<boost::mutex> lock(mutex);
if (active == max && !queue.empty()) {
// if all available threads are already running
// and there's work waiting, just run in current thread
lock.unlock();
f();
} else {
if (obj)
obj->inc();
queue.push_back(e);
has_work.notify_one();
}
}
int threadpool::get_max_concurrency() {
return max / 2;
}
void threadpool::waiter::wait() {
boost::unique_lock<boost::mutex> lock(mt);
while(num) cv.wait(lock);
}
void threadpool::waiter::inc() {
const boost::unique_lock<boost::mutex> lock(mt);
num++;
}
void threadpool::waiter::dec() {
const boost::unique_lock<boost::mutex> lock(mt);
num--;
if (!num)
cv.notify_one();
}
void threadpool::run() {
boost::unique_lock<boost::mutex> lock(mutex);
while (running) {
entry e;
while(queue.empty() && running)
has_work.wait(lock);
if (!running) break;
active++;
e = queue.front();
queue.pop_front();
lock.unlock();
e.f();
if (e.wo)
e.wo->dec();
lock.lock();
active--;
}
}
}