ceph/src/boost/libs/asio/test/latency/high_res_clock.hpp

   1 //
   2 // high_res_clock.hpp
   3 // ~~~~~~~~~~~~~~~~~~
   4 //
   5 // Copyright (c) 2003-2017 Christopher M. Kohlhoff (chris at kohlhoff dot com)
   6 //
   7 // Distributed under the Boost Software License, Version 1.0. (See accompanying
   8 // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
   9 //
  10
  11 #ifndef HIGH_RES_CLOCK_HPP
  12 #define HIGH_RES_CLOCK_HPP
  13
  14 #include <boost/config.hpp>
  15 #include <boost/cstdint.hpp>
  16
  17 #if defined(BOOST_ASIO_WINDOWS)
  18
  19 inline boost::uint64_t high_res_clock()
  20 {
  21   LARGE_INTEGER i;
  22   QueryPerformanceCounter(&i);
  23   return i.QuadPart;
  24 }
  25
  26 #elif defined(__GNUC__) && defined(__x86_64__)
  27
  28 inline boost::uint64_t high_res_clock()
  29 {
  30   unsigned long low, high;
  31   __asm__ __volatile__("rdtsc" : "=a" (low), "=d" (high));
  32   return (((boost::uint64_t)high) << 32) | low;
  33 }
  34
  35 #else
  36
  37 #include <boost/date_time/posix_time/posix_time_types.hpp>
  38
  39 inline boost::uint64_t high_res_clock()
  40 {
  41   boost::posix_time::ptime now =
  42     boost::posix_time::microsec_clock::universal_time();
  43
  44   boost::posix_time::ptime epoch(
  45       boost::gregorian::date(1970, 1, 1),
  46       boost::posix_time::seconds(0));
  47
  48   return (now - epoch).total_microseconds();
  49 }
  50
  51 #endif
  52
  53 #endif // HIGH_RES_CLOCK_HPP