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Re: Some help needed

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So as the timings of the PAUSE-instructions are so different I
decided to write a singleton containing the fastest timing of
the PAUSE-instruction on the machine. This is the code:

cpu_pause.h:

#pragma once
#if defined(_MSC_VER) && (defined(_M_X64) || defined(_M_IX86))
	#include <intrin.h>
#elif defined(__GNUC__) && (defined(__x86_64__) || defined(__i386__))
	#include <immintrin.h>
#else
	#error "need platform-specific pause-instruction"
#endif

inline
void cpu_pause()
{
#if defined(_MSC_VER) && (defined(_M_X64) || defined(_M_IX86)) || 
defined(__GNUC__) && (defined(__x86_64__) || defined(__i386__))
	_mm_pause();
#endif
}

inline
void cpu_pause_n( unsigned iterations )
{
	for( ; iterations--; cpu_pause() );
}

struct pause_singleton
{
	static
	double getNsPerPause();
private:
	static
	struct singleton_t
	{
		singleton_t();
		double m_nsPerPause;
	} singleton;
};

inline
double pause_singleton::getNsPerPause()
{
	return singleton.m_nsPerPause;
}

cpu_pasue.h:

#include <chrono>
#include <limits>
#include "cpu_pause.h"

using namespace std;
using namespace chrono;

#if defined(_MSC_VER)
	#pragma warning(disable: 26495) // member not initialized
	#pragma warning(disable: 26498) // consider constexpr
#endif

pause_singleton::singleton_t::singleton_t()
{
	int64_t leastTicks = numeric_limits<int64_t>::max();;
	for( size_t i = 1000; i; --i )
	{
		auto start = high_resolution_clock::now();
		for( size_t j = 1'000; j; --j )
			cpu_pause();
		int64_t ticks = (int64_t)duration_cast<nanoseconds>( 
high_resolution_clock::now() - start ).count();
		if( ticks < leastTicks )
			leastTicks = ticks;
	}
	m_nsPerPause = leastTicks / 1'000.0;
}

pause_singleton::singleton_t pause_singleton::singleton;

So I can adjust the spinning-loop according
to pause_singleton::getNsPerPause().

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Some help needed Bonita Montero <Bonita.Montero@gmail.com> - 2021-09-25 16:41 +0200
  Re: Some help needed Paavo Helde <myfirstname@osa.pri.ee> - 2021-09-25 19:51 +0300
    Re: Some help needed Bonita Montero <Bonita.Montero@gmail.com> - 2021-09-25 19:01 +0200
    Re: Some help needed Branimir Maksimovic <branimir.maksimovic@gmail.com> - 2021-09-25 17:20 +0000
  Re: Some help needed Bo Persson <bo@bo-persson.se> - 2021-09-25 19:05 +0200
    Re: Some help needed Bonita Montero <Bonita.Montero@gmail.com> - 2021-09-25 19:14 +0200
    Re: Some help needed Branimir Maksimovic <branimir.maksimovic@gmail.com> - 2021-09-25 17:33 +0000
  Re: Some help needed Branimir Maksimovic <branimir.maksimovic@gmail.com> - 2021-09-25 17:15 +0000
    Re: Some help needed Bonita Montero <Bonita.Montero@gmail.com> - 2021-09-25 19:16 +0200
      Re: Some help needed Branimir Maksimovic <branimir.maksimovic@gmail.com> - 2021-09-25 17:29 +0000
  Re: Some help needed Bonita Montero <Bonita.Montero@gmail.com> - 2021-09-26 07:26 +0200
    Re: Some help needed Branimir Maksimovic <branimir.maksimovic@gmail.com> - 2021-09-26 06:56 +0000
    Re: Some help needed - further help Bonita Montero <Bonita.Montero@gmail.com> - 2021-09-27 17:35 +0200
      Re: Some help needed - further help Bo Persson <bo@bo-persson.se> - 2021-09-27 19:29 +0200

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