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#include "hp_timer.h"
#include <util/generic/algorithm.h>
#include <util/generic/singleton.h>
#include <util/datetime/cputimer.h>
using namespace NHPTimer;
namespace {
struct TFreq {
inline TFreq()
: Freq(InitHPTimer())
, Rate(1.0 / Freq)
, CyclesPerSecond(static_cast<ui64>(Rate))
{
}
static inline const TFreq& Instance() {
return *SingletonWithPriority<TFreq, 1>();
}
static double EstimateCPUClock() {
for (;;) {
ui64 startCycle = 0;
ui64 startMS = 0;
for (;;) {
startMS = MicroSeconds();
startCycle = GetCycleCount();
ui64 n = MicroSeconds();
if (n - startMS < 100) {
break;
}
}
Sleep(TDuration::MicroSeconds(5000));
ui64 finishCycle = 0;
ui64 finishMS = 0;
for (;;) {
finishMS = MicroSeconds();
if (finishMS - startMS < 100) {
continue;
}
finishCycle = GetCycleCount();
ui64 n = MicroSeconds();
if (n - finishMS < 100) {
break;
}
}
if (startMS < finishMS && startCycle < finishCycle) {
return (finishCycle - startCycle) * 1000000.0 / (finishMS - startMS);
}
}
}
static double InitHPTimer() {
const size_t N_VEC = 9;
double vec[N_VEC];
for (auto& i : vec) {
i = EstimateCPUClock();
}
Sort(vec, vec + N_VEC);
return 1.0 / vec[N_VEC / 2];
}
inline double GetSeconds(const STime& a) const {
return static_cast<double>(a) * Freq;
}
inline double GetClockRate() const {
return Rate;
}
inline ui64 GetCyclesPerSecond() const {
return CyclesPerSecond;
}
const double Freq;
const double Rate;
const ui64 CyclesPerSecond;
};
}
double NHPTimer::GetSeconds(const STime& a) noexcept {
return TFreq::Instance().GetSeconds(a);
}
double NHPTimer::GetClockRate() noexcept {
return TFreq::Instance().GetClockRate();
}
ui64 NHPTimer::GetCyclesPerSecond() noexcept {
return TFreq::Instance().GetCyclesPerSecond();
}
void NHPTimer::GetTime(STime* pTime) noexcept {
*pTime = GetCycleCount();
}
double NHPTimer::GetTimePassed(STime* pTime) noexcept {
STime old(*pTime);
*pTime = GetCycleCount();
return GetSeconds(*pTime - old);
}
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