ceph/src/boost/libs/fiber/performance/thread/overhead_detach.cpp

   1
   2 //          Copyright Oliver Kowalke 2009.
   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 #include <cstdlib>
   8 #include <iostream>
   9 #include <stdexcept>
  10 #include <string>
  11 #include <thread>
  12
  13 #include <boost/cstdint.hpp>
  14 #include <boost/preprocessor.hpp>
  15 #include <boost/program_options.hpp>
  16
  17 #include "../clock.hpp"
  18
  19 #ifndef JOBS
  20 #define JOBS BOOST_PP_LIMIT_REPEAT
  21 #endif
  22
  23 #define DETACH(z, n, _) \
  24 { \
  25     std::thread t( worker); \
  26     time_point_type start( clock_type::now() ); \
  27     t.detach(); \
  28     duration_type total = clock_type::now() - start; \
  29     total -= overhead; \
  30     result += total; \
  31 }
  32
  33 void worker() {}
  34
  35 duration_type measure( duration_type overhead)
  36 {
  37     std::thread( worker).join();
  38
  39     duration_type result = duration_type::zero();
  40
  41     BOOST_PP_REPEAT_FROM_TO(1, JOBS, DETACH, _)
  42
  43     result /= JOBS;  // loops
  44
  45     return result;
  46 }
  47
  48 int main( int argc, char * argv[])
  49 {
  50     try
  51     {
  52         duration_type overhead = overhead_clock();
  53         boost::uint64_t res = measure( overhead).count();
  54         std::cout << "average of " << res << " nano seconds" << std::endl;
  55
  56         return EXIT_SUCCESS;
  57     }
  58     catch ( std::exception const& e)
  59     { std::cerr << "exception: " << e.what() << std::endl; }
  60     catch (...)
  61     { std::cerr << "unhandled exception" << std::endl; }
  62     return EXIT_FAILURE;
  63 }