ceph/src/boost/libs/fiber/performance/fiber/skynet_join.cpp

   1
   2 //          Copyright Oliver Kowalke 2015.
   3 // Distributed under the Boost Software License, Version 1.0.
   4 //    (See accompanying file LICENSE_1_0.txt or copy at
   5 //          http://www.boost.org/LICENSE_1_0.txt)
   6
   7 // based on https://github.com/atemerev/skynet from Alexander Temerev
   8
   9 #include <algorithm>
  10 #include <cassert>
  11 #include <chrono>
  12 #include <cmath>
  13 #include <cstddef>
  14 #include <cstdint>
  15 #include <cstdlib>
  16 #include <iostream>
  17 #include <memory>
  18 #include <numeric>
  19 #include <vector>
  20
  21 #include <boost/fiber/all.hpp>
  22 #include <boost/predef.h>
  23
  24 using allocator_type = boost::fibers::fixedsize_stack;
  25 using channel_type = boost::fibers::buffered_channel< std::uint64_t >;
  26 using clock_type = std::chrono::steady_clock;
  27 using duration_type = clock_type::duration;
  28 using time_point_type = clock_type::time_point;
  29
  30 // microbenchmark
  31 void skynet( allocator_type & salloc, channel_type & c, std::size_t num, std::size_t size, std::size_t div) {
  32     if ( 1 == size) {
  33         c.push( num);
  34     } else {
  35         channel_type rc{ 16 };
  36         std::vector< boost::fibers::fiber > fibers;
  37         for ( std::size_t i = 0; i < div; ++i) {
  38             auto sub_num = num + i * size / div;
  39             fibers.emplace_back( boost::fibers::launch::dispatch,
  40                                  std::allocator_arg, salloc,
  41                                  skynet,
  42                                  std::ref( salloc), std::ref( rc), sub_num, size / div, div);
  43         }
  44         for ( auto & f: fibers) {
  45             f.join();
  46         }
  47         std::uint64_t sum{ 0 };
  48         for ( std::size_t i = 0; i < div; ++i) {
  49             sum += rc.value_pop();
  50         }
  51         c.push( sum);
  52     }
  53 }
  54
  55 int main() {
  56     try {
  57         std::size_t size{ 1000000 };
  58         std::size_t div{ 10 };
  59         // Windows 10 and FreeBSD require a fiber stack of 8kb
  60         // otherwise the stack gets exhausted
  61         // stack requirements must be checked for other OS too
  62 #if BOOST_OS_WINDOWS || BOOST_OS_BSD
  63         allocator_type salloc{ 2*allocator_type::traits_type::page_size() };
  64 #else
  65         allocator_type salloc{ allocator_type::traits_type::page_size() };
  66 #endif
  67         std::uint64_t result{ 0 };
  68         channel_type rc{ 2 };
  69         time_point_type start{ clock_type::now() };
  70         skynet( salloc, rc, 0, size, div);
  71         result = rc.value_pop();
  72         if ( 499999500000 != result) {
  73             throw std::runtime_error("invalid result");
  74         }
  75         auto duration = clock_type::now() - start;
  76         std::cout << "duration: " << duration.count() / 1000000 << " ms" << std::endl;
  77         return EXIT_SUCCESS;
  78     } catch ( std::exception const& e) {
  79         std::cerr << "exception: " << e.what() << std::endl;
  80     } catch (...) {
  81         std::cerr << "unhandled exception" << std::endl;
  82     }
  83         return EXIT_FAILURE;
  84 }