// Copyright Oliver Kowalke 2015.
// Distributed under the Boost Software License, Version 1.0.
// (See accompanying file LICENSE_1_0.txt or copy at
// http://www.boost.org/LICENSE_1_0.txt)
// based on https://github.com/atemerev/skynet from Alexander Temerev
#include <algorithm>
#include <cassert>
#include <chrono>
#include <cmath>
#include <cstddef>
#include <cstdint>
#include <cstdlib>
#include <iostream>
#include <memory>
#include <numeric>
#include <vector>
#include <boost/fiber/all.hpp>
#include <boost/predef.h>
using allocator_type = boost::fibers::fixedsize_stack;
using channel_type = boost::fibers::buffered_channel< std::uint64_t >;
using clock_type = std::chrono::steady_clock;
using duration_type = clock_type::duration;
using time_point_type = clock_type::time_point;
// microbenchmark
void skynet( allocator_type & salloc, channel_type & c, std::size_t num, std::size_t size, std::size_t div) {
if ( 1 == size) {
c.push( num);
} else {
channel_type rc{ 16 };
std::vector< boost::fibers::fiber > fibers;
for ( std::size_t i = 0; i < div; ++i) {
auto sub_num = num + i * size / div;
fibers.emplace_back( boost::fibers::launch::dispatch,
std::allocator_arg, salloc,
skynet,
std::ref( salloc), std::ref( rc), sub_num, size / div, div);
}
for ( auto & f: fibers) {
f.join();
}
std::uint64_t sum{ 0 };
for ( std::size_t i = 0; i < div; ++i) {
sum += rc.value_pop();
}
c.push( sum);
}
}
int main() {
try {
std::size_t size{ 1000000 };
std::size_t div{ 10 };
// Windows 10 and FreeBSD require a fiber stack of 8kb
// otherwise the stack gets exhausted
// stack requirements must be checked for other OS too
#if BOOST_OS_WINDOWS || BOOST_OS_BSD
allocator_type salloc{ 2*allocator_type::traits_type::page_size() };
#else
allocator_type salloc{ allocator_type::traits_type::page_size() };
#endif
std::uint64_t result{ 0 };
channel_type rc{ 2 };
time_point_type start{ clock_type::now() };
skynet( salloc, rc, 0, size, div);
result = rc.value_pop();
if ( 499999500000 != result) {
throw std::runtime_error("invalid result");
}
auto duration = clock_type::now() - start;
std::cout << "duration: " << duration.count() / 1000000 << " ms" << std::endl;
return EXIT_SUCCESS;
} catch ( std::exception const& e) {
std::cerr << "exception: " << e.what() << std::endl;
} catch (...) {
std::cerr << "unhandled exception" << std::endl;
}
return EXIT_FAILURE;
}