ceph/src/boost/libs/fiber/performance/fiber/skynet_stealing_detach.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 <condition_variable>
  14 #include <cstddef>
  15 #include <cstdint>
  16 #include <cstdlib>
  17 #include <queue>
  18 #include <iostream>
  19 #include <memory>
  20 #include <mutex>
  21 #include <numeric>
  22 #include <random>
  23 #include <sstream>
  24 #include <vector>
  25
  26 #include <boost/fiber/all.hpp>
  27 #include <boost/predef.h>
  28
  29 #include "barrier.hpp"
  30
  31 using clock_type = std::chrono::steady_clock;
  32 using duration_type = clock_type::duration;
  33 using time_point_type = clock_type::time_point;
  34 using channel_type = boost::fibers::buffered_channel< std::uint64_t >;
  35 using allocator_type = boost::fibers::fixedsize_stack;
  36 using lock_type = std::unique_lock< std::mutex >;
  37
  38 static bool done = false;
  39 static std::mutex mtx{};
  40 static boost::fibers::condition_variable_any cnd{};
  41
  42 // microbenchmark
  43 void skynet( allocator_type & salloc, channel_type & c, std::size_t num, std::size_t size, std::size_t div) {
  44     if ( 1 == size) {
  45         c.push( num);
  46     } else {
  47         channel_type rc{ 16 };
  48         for ( std::size_t i = 0; i < div; ++i) {
  49             auto sub_num = num + i * size / div;
  50             boost::fibers::fiber{ boost::fibers::launch::dispatch,
  51                               std::allocator_arg, salloc,
  52                               skynet,
  53                               std::ref( salloc), std::ref( rc), sub_num, size / div, div }.detach();
  54         }
  55         std::uint64_t sum{ 0 };
  56         for ( std::size_t i = 0; i < div; ++i) {
  57             sum += rc.value_pop();
  58         }
  59         c.push( sum);
  60     }
  61 }
  62
  63 void thread( std::uint32_t thread_count, barrier * b) {
  64     // thread registers itself at work-stealing scheduler
  65     boost::fibers::use_scheduling_algorithm< boost::fibers::algo::work_stealing >( thread_count);
  66     b->wait();
  67     lock_type lk( mtx);
  68     cnd.wait( lk, [](){ return done; });
  69     BOOST_ASSERT( done);
  70 }
  71
  72 int main() {
  73     try {
  74         // count of logical cpus
  75         std::uint32_t thread_count = std::thread::hardware_concurrency();
  76         // main-thread registers itself at work-stealing scheduler
  77         boost::fibers::use_scheduling_algorithm< boost::fibers::algo::work_stealing >( thread_count);
  78         barrier b{ thread_count };
  79         std::size_t size{ 1000000 };
  80         std::size_t div{ 10 };
  81         // Windows 10 and FreeBSD require a fiber stack of 8kb
  82         // otherwise the stack gets exhausted
  83         // stack requirements must be checked for other OS too
  84 #if BOOST_OS_WINDOWS || BOOST_OS_BSD
  85         allocator_type salloc{ 2*allocator_type::traits_type::page_size() };
  86 #else
  87         allocator_type salloc{ allocator_type::traits_type::page_size() };
  88 #endif
  89         std::uint64_t result{ 0 };
  90         channel_type rc{ 2 };
  91         std::vector< std::thread > threads;
  92         for ( std::uint32_t i = 1 /* count main-thread */; i < thread_count; ++i) {
  93             // spawn thread
  94             threads.emplace_back( thread, thread_count, & b);
  95         }
  96         b.wait();
  97         time_point_type start{ clock_type::now() };
  98         skynet( salloc, rc, 0, size, div);
  99         result = rc.value_pop();
 100         if ( 499999500000 != result) {
 101             throw std::runtime_error("invalid result");
 102         }
 103         auto duration = clock_type::now() - start;
 104         lock_type lk( mtx);
 105         done = true;
 106         lk.unlock();
 107         cnd.notify_all();
 108         for ( std::thread & t : threads) {
 109             t.join();
 110         }
 111         std::cout << "duration: " << duration.count() / 1000000 << " ms" << std::endl;
 112         return EXIT_SUCCESS;
 113     } catch ( std::exception const& e) {
 114         std::cerr << "exception: " << e.what() << std::endl;
 115     } catch (...) {
 116         std::cerr << "unhandled exception" << std::endl;
 117     }
 118         return EXIT_FAILURE;
 119 }