timestamp_clock_posix.cc

#include <embb/base/perf/timer.h>

#if defined(EMBB_BASE_CPP_PERF_TIMER_POSIX) || \
    defined(EMBB_BASE_CPP_PERF_TIMER_OSX) || \
    defined(EMBB_BASE_CPP_PERF_TIMER_UX)

#include <embb/base/perf/internal/timestamp_clock_posix.h>

#include <stdexcept>

// POSIX standard header
#include <unistd.h>   /* POSIX flags */
#include <time.h>	    /* clock_gettime(), time(), needs librt.a */
#include <sys/time.h>	/* gethrtime(), gettimeofday() */

#if defined(__MACH__) && defined(__APPLE__)
// OS X / Mach 
#include <mach/mach.h>
#include <mach/mach_time.h>
#endif 

namespace embb {
namespace base {
namespace perf {
namespace internal {
namespace timer {

TimestampClockPosix::TimestampClockPosix() {
// {{{{
#if defined(EMBB_BASE_CPP_PERF_TIMER_UX)
// HP-UX, Solaris
  value = static_cast<Timestamp::counter_t>(gethrtime());

#elif defined(EMBB_BASE_CPP_PERF_TIMER_OSX)
// OS X 
  static double timeConvert = 0.0;
  if (timeConvert == 0.0)
  {
    mach_timebase_info_data_t timeBase;
    (void)mach_timebase_info(&timeBase);
    timeConvert = (double)timeBase.numer / 
                  (double)timeBase.denom;
  }
  value = static_cast<Timestamp::counter_t>(
            static_cast<double>(mach_absolute_time() * timeConvert));

#elif defined(EMBB_BASE_CPP_PERF_TIMER_POSIX)
// POSIX
#if defined(_POSIX_TIMERS) && (_POSIX_TIMERS > 0) 
// POSIX clock_gettime
  struct timespec ts;

  if (clockId != (clockid_t)-1 && clock_gettime(clockId, &ts) != -1) {
    value = static_cast<Timestamp::counter_t>(
              static_cast<double>(ts.tv_sec * 1000000) + 
              static_cast<double>(ts.tv_nsec / 1000)); 
    return;
  }

#endif 
// No support for POSIX clock_gettime
  // Imprecise fallback to wall-clock time
  struct timeval tm;
  gettimeofday(&tm, NULL);
  value = static_cast<Timestamp::counter_t>(
            static_cast<double>(ts.tv_sec * 1000000) + 
            static_cast<double>(ts.tv_nsec / 1000)); 
#else
// No POSIX-compliant time mechanism found. 
  throw std::runtime_error("Could not resolve timer"); 
#endif
// }}}
}

const char * 
TimestampClockPosix::clockModeNames[] = {
// {{{
  "Default", 
  "GENERIC",
  "UX", 
  "MACH", 
  "THREAD_CPUTIME", 
  "PROC_CPUTIME", 
  "HIGHRES", 
  "MONOTONIC_PRECISE", 
  "MONOTONIC_RAW", 
  "MONOTONIC", 
  "REALTIME"
// }}}
};

TimestampClockPosix::ClockDef
TimestampClockPosix::availableModes[] = {
// {{{
  TimestampClockPosix::ClockDef(
      UNDEFINED_CLOCK,   static_cast<clockid_t>(-1)), 
#if defined(EMBB_BASE_CPP_PERF_TIMER_UX)
  TimestampClockPosix::ClockDef(
      UX,                static_cast<clockid_t>(-1)), 
#endif
#if defined(EMBB_BASE_CPP_PERF_TIMER_OSX)
  TimestampClockPosix::ClockDef(
      MACH,              static_cast<clockid_t>(-1)), 
#endif
#if defined(_CLOCK_HIGHRES)
  TimestampClockPosix::ClockDef(
      HIGHRES,           CLOCK_HIGHRES), 
#endif
#if defined(_POSIX_MONOTONIC_CLOCK)
# if defined(EMBB_BASE_CPP_PERF_TIMER_FREEBSD)
  TimestampClockPosix::ClockDef(
      MONOTONIC_PRECISE, CLOCK_MONOTONIC_PRECISE), 
  ///< FreeBSD specific, correcponds to MONOTONIC on Linux
# endif // FreeBSD
# if defined(EMBB_BASE_CPP_PERF_TIMER_LINUX)
  TimestampClockPosix::ClockDef(
      MONOTONIC_RAW,     CLOCK_MONOTONIC_RAW), 
  ///< Linux specific, like MONOTONIC but without NTP adjustment
# endif // Linux
  TimestampClockPosix::ClockDef(
      MONOTONIC,         CLOCK_MONOTONIC), 
#endif // _POSIX_MONOTONIC_CLOCK
#if defined(_POSIX_THREAD_CPUTIME)
  TimestampClockPosix::ClockDef(
      THREAD_CPUTIME,    CLOCK_THREAD_CPUTIME_ID), 
#endif
#if defined(_POSIX_CPUTIME)
  TimestampClockPosix::ClockDef(
      PROC_CPUTIME,      CLOCK_PROCESS_CPUTIME_ID), 
#endif
  TimestampClockPosix::ClockDef(
      REALTIME,          CLOCK_REALTIME), 
  TimestampClockPosix::ClockDef(
      GENERIC_CLOCK,     static_cast<clockid_t>(-1))
// }}}
}; 

void TimestampClockPosix::
Calibrate(unsigned int mode) { 
// {{{
  const unsigned int lastAvMode = static_cast<unsigned int>(
    TimestampClockPosix::GENERIC_CLOCK);
  // Default to second index in available modes, which 
  // is the first and preferred clock type
  unsigned int selectedModeIndex  = 1; 
  // Iterate over all available clock types: 
  std::cout << "Available modes: "; 
  for (unsigned int avModeIdx = 1; 
      TimestampClockPosix::availableModes[avModeIdx].first != lastAvMode; 
       ++avModeIdx) {
    unsigned int modeNum = TimestampClockPosix::availableModes[avModeIdx].first; 
    if (modeNum == mode) { 
      // Selected mode id is contained in available modes
      selectedModeIndex = avModeIdx; 
    }
    std::cout << TimestampClockPosix::clockModeNames[modeNum] 
              << "(" << modeNum << ") "; 
  }
  std::cout << std::endl; 
  
  clockMode = TimestampClockPosix::availableModes[selectedModeIndex].first;
  clockId   = TimestampClockPosix::availableModes[selectedModeIndex].second;
  // Print mode that finally has been activated: 
  unsigned int modeNum = static_cast<unsigned int>(clockMode);
  std::cout << "Active mode:     " 
            << TimestampClockPosix::clockModeNames[modeNum] 
            << "(" << modeNum << ")" << std::endl; 
  // Print resolution of the active clock: 
  struct timespec res; 
  if (clock_getres(clockId, &res) == 0) {
    std::cout << "Resolution:      " << res.tv_nsec << "ns" << std::endl;
  }
// }}}
}

TimestampClockPosix::ClockMode 
TimestampClockPosix::clockMode = TimestampClockPosix::UNDEFINED_CLOCK;

clockid_t 
TimestampClockPosix::clockId = static_cast<clockid_t>(-1); 

Timestamp::counter_t 
TimestampClockPosix::frequencyScaling = 1;

} // namespace timer
} // namespace internal
} // namespace perf
} // namespace base
} // namespace embb

#endif // POSIX || OSX || UX