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Replace QPC to RDTSC Timer in games

https://forums.blurbusters.com/viewtopic.php?t=8885

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Re: Replace QPC to RDTSC Timer in games

Posted: 15 Aug 2021, 14:25
by Kaldaien
I'm not convinced this is a good idea :)

The reason we moved away from using RDTSC for timing is because 1) CPUs have dynamic frequency scaling and 2) each CPU core has a different RDTSC timestamp.

QPC is monotonic and the frequency is constant no matter what CPU core any timing code happens to be running on.

Re: Replace QPC to RDTSC Timer in games

Posted: 26 Dec 2021, 11:47
by pox02
i would like to update code so u guys get more game feeling by using the function QueryThreadCycleTime enjoy :D

Code: Select all

LONGLONG GetFrequency(DWORD sleepTime)
{
    LARGE_INTEGER fq, st, ed;
    QueryPerformanceFrequency(&fq);
    QueryPerformanceCounter(&st);
    QueryThreadCycleTime(GetCurrentThread(), &st);
    LONGLONG begin = GetCycleCount();
    Sleep(sleepTime);
    QueryPerformanceCounter(&ed);
    QueryThreadCycleTime(GetCurrentThread(), &ed);
    LONGLONG end = GetCycleCount();
    return (end - begin) * fq.QuadPart / (ed.QuadPart - st.QuadPart);
}

Re: Replace QPC to RDTSC Timer in games

Posted: 26 Dec 2021, 18:47
by Bobo
what exactly is this and how do you use it ?

Re: Replace QPC to RDTSC Timer in games

Posted: 27 Dec 2021, 12:12
by Aspector
pox02 wrote: ↑
26 Dec 2021, 11:47
 i would like to update code so u guys get more game feeling by using the function QueryThreadCycleTime enjoy :D

Code: Select all

LONGLONG GetFrequency(DWORD sleepTime)
{
    LARGE_INTEGER fq, st, ed;
    QueryPerformanceFrequency(&fq);
    QueryPerformanceCounter(&st);
    QueryThreadCycleTime(GetCurrentThread(), &st);
    LONGLONG begin = GetCycleCount();
    Sleep(sleepTime);
    QueryPerformanceCounter(&ed);
    QueryThreadCycleTime(GetCurrentThread(), &ed);
    LONGLONG end = GetCycleCount();
    return (end - begin) * fq.QuadPart / (ed.QuadPart - st.QuadPart);
}
And how do we use it or compile it?

Re: Replace QPC to RDTSC Timer in games

Posted: 27 Dec 2021, 13:29
by AndreyRGW
pox02 wrote: ↑
26 Dec 2021, 11:47
 i would like to update code so u guys get more game feeling by using the function QueryThreadCycleTime enjoy :D

Code: Select all

LONGLONG GetFrequency(DWORD sleepTime)
{
    LARGE_INTEGER fq, st, ed;
    QueryPerformanceFrequency(&fq);
    QueryPerformanceCounter(&st);
    QueryThreadCycleTime(GetCurrentThread(), &st);
    LONGLONG begin = GetCycleCount();
    Sleep(sleepTime);
    QueryPerformanceCounter(&ed);
    QueryThreadCycleTime(GetCurrentThread(), &ed);
    LONGLONG end = GetCycleCount();
    return (end - begin) * fq.QuadPart / (ed.QuadPart - st.QuadPart);
}
I compiled RDTSC with your code, but I didn't notice any changes compared to the original.

Re: Replace QPC to RDTSC Timer in games

Posted: 27 Dec 2021, 14:48
by pox02
AndreyRGW wrote: ↑
27 Dec 2021, 13:29
pox02 wrote: ↑
26 Dec 2021, 11:47
 i would like to update code so u guys get more game feeling by using the function QueryThreadCycleTime enjoy :D

Code: Select all

LONGLONG GetFrequency(DWORD sleepTime)
{
    LARGE_INTEGER fq, st, ed;
    QueryPerformanceFrequency(&fq);
    QueryPerformanceCounter(&st);
    QueryThreadCycleTime(GetCurrentThread(), &st);
    LONGLONG begin = GetCycleCount();
    Sleep(sleepTime);
    QueryPerformanceCounter(&ed);
    QueryThreadCycleTime(GetCurrentThread(), &ed);
    LONGLONG end = GetCycleCount();
    return (end - begin) * fq.QuadPart / (ed.QuadPart - st.QuadPart);
}
I compiled RDTSC with your code, but I didn't notice any changes compared to the original.
Try add SetProcessAffinityMask in first core see if any improvement

Code: Select all

SetProcessAffinityMask(GetCurrentProcess(), 1);
test fix overhead of QueryPerformanceCounter didnt try for long time so give any updates of it

Code: Select all

 LARGE_INTEGER fq, st, ed;
    QueryPerformanceFrequency(&fq);
    QueryPerformanceCounter(&st);
    LONGLONG begin = GetCycleCount();
    Sleep(sleepTime);
    QueryPerformanceCounter(&ed);
    1000000 * (ed.QuadPart - st.QuadPart), fq;
    LONGLONG end = GetCycleCount();
    return (end - begin) * fq.QuadPart / (ed.QuadPart - st.QuadPart);

Re: Replace QPC to RDTSC Timer in games

Posted: 28 Dec 2021, 08:54
by AndreyRGW
pox02 wrote: ↑
27 Dec 2021, 14:48
AndreyRGW wrote: ↑
27 Dec 2021, 13:29
pox02 wrote: ↑
26 Dec 2021, 11:47
 i would like to update code so u guys get more game feeling by using the function QueryThreadCycleTime enjoy :D

Code: Select all

LONGLONG GetFrequency(DWORD sleepTime)
{
    LARGE_INTEGER fq, st, ed;
    QueryPerformanceFrequency(&fq);
    QueryPerformanceCounter(&st);
    QueryThreadCycleTime(GetCurrentThread(), &st);
    LONGLONG begin = GetCycleCount();
    Sleep(sleepTime);
    QueryPerformanceCounter(&ed);
    QueryThreadCycleTime(GetCurrentThread(), &ed);
    LONGLONG end = GetCycleCount();
    return (end - begin) * fq.QuadPart / (ed.QuadPart - st.QuadPart);
}
I compiled RDTSC with your code, but I didn't notice any changes compared to the original.
Try add SetProcessAffinityMask in first core see if any improvement

Code: Select all

SetProcessAffinityMask(GetCurrentProcess(), 1);
test fix overhead of QueryPerformanceCounter didnt try for long time so give any updates of it

Code: Select all

 LARGE_INTEGER fq, st, ed;
    QueryPerformanceFrequency(&fq);
    QueryPerformanceCounter(&st);
    LONGLONG begin = GetCycleCount();
    Sleep(sleepTime);
    QueryPerformanceCounter(&ed);
    1000000 * (ed.QuadPart - st.QuadPart), fq;
    LONGLONG end = GetCycleCount();
    return (end - begin) * fq.QuadPart / (ed.QuadPart - st.QuadPart);
I think it only got worse after that.

Re: Replace QPC to RDTSC Timer in games

Posted: 31 Dec 2021, 23:53
by pox02
AndreyRGW wrote: ↑
28 Dec 2021, 08:54
pox02 wrote: ↑
27 Dec 2021, 14:48
AndreyRGW wrote: ↑
27 Dec 2021, 13:29
pox02 wrote: ↑
26 Dec 2021, 11:47
 i would like to update code so u guys get more game feeling by using the function QueryThreadCycleTime enjoy :D

Code: Select all

LONGLONG GetFrequency(DWORD sleepTime)
{
    LARGE_INTEGER fq, st, ed;
    QueryPerformanceFrequency(&fq);
    QueryPerformanceCounter(&st);
    QueryThreadCycleTime(GetCurrentThread(), &st);
    LONGLONG begin = GetCycleCount();
    Sleep(sleepTime);
    QueryPerformanceCounter(&ed);
    QueryThreadCycleTime(GetCurrentThread(), &ed);
    LONGLONG end = GetCycleCount();
    return (end - begin) * fq.QuadPart / (ed.QuadPart - st.QuadPart);
}
I compiled RDTSC with your code, but I didn't notice any changes compared to the original.
Try add SetProcessAffinityMask in first core see if any improvement

Code: Select all

SetProcessAffinityMask(GetCurrentProcess(), 1);
test fix overhead of QueryPerformanceCounter didnt try for long time so give any updates of it

Code: Select all

 LARGE_INTEGER fq, st, ed;
    QueryPerformanceFrequency(&fq);
    QueryPerformanceCounter(&st);
    LONGLONG begin = GetCycleCount();
    Sleep(sleepTime);
    QueryPerformanceCounter(&ed);
    1000000 * (ed.QuadPart - st.QuadPart), fq;
    LONGLONG end = GetCycleCount();
    return (end - begin) * fq.QuadPart / (ed.QuadPart - st.QuadPart);
I think it only got worse after that.
i see one last attempt

Code: Select all

LONGLONG GetFrequency(DWORD sleepTime)
{
    LARGE_INTEGER fq, st, ed;
    SetPriorityClass(GetCurrentThread(), REALTIME_PRIORITY_CLASS);
    SetThreadPriority(GetCurrentThread(), THREAD_PRIORITY_TIME_CRITICAL);
    SetProcessPriorityBoost(GetCurrentThread(), 0);
    SetThreadAffinityMask(GetCurrentThread(), 0x1);
    SetProcessAffinityMask(GetCurrentProcess(), 0x0);
    QueryPerformanceFrequency(&fq);
    QueryPerformanceCounter(&st);
    LONGLONG begin = GetCycleCount();
	Sleep(sleepTime);
    QueryPerformanceCounter(&ed);
    LONGLONG end = GetCycleCount();
    return (end - begin) * fq.QuadPart / (ed.QuadPart - st.QuadPart);
}

Re: Replace QPC to RDTSC Timer in games

Posted: 01 Jan 2022, 15:49
by AndreyRGW
pox02 wrote: ↑
31 Dec 2021, 23:53
AndreyRGW wrote: ↑
28 Dec 2021, 08:54
pox02 wrote: ↑
27 Dec 2021, 14:48
AndreyRGW wrote: ↑
27 Dec 2021, 13:29

I compiled RDTSC with your code, but I didn't notice any changes compared to the original.
Try add SetProcessAffinityMask in first core see if any improvement

Code: Select all

SetProcessAffinityMask(GetCurrentProcess(), 1);
test fix overhead of QueryPerformanceCounter didnt try for long time so give any updates of it

Code: Select all

 LARGE_INTEGER fq, st, ed;
    QueryPerformanceFrequency(&fq);
    QueryPerformanceCounter(&st);
    LONGLONG begin = GetCycleCount();
    Sleep(sleepTime);
    QueryPerformanceCounter(&ed);
    1000000 * (ed.QuadPart - st.QuadPart), fq;
    LONGLONG end = GetCycleCount();
    return (end - begin) * fq.QuadPart / (ed.QuadPart - st.QuadPart);
I think it only got worse after that.
i see one last attempt

Code: Select all

LONGLONG GetFrequency(DWORD sleepTime)
{
    LARGE_INTEGER fq, st, ed;
    SetPriorityClass(GetCurrentThread(), REALTIME_PRIORITY_CLASS);
    SetThreadPriority(GetCurrentThread(), THREAD_PRIORITY_TIME_CRITICAL);
    SetProcessPriorityBoost(GetCurrentThread(), 0);
    SetThreadAffinityMask(GetCurrentThread(), 0x1);
    SetProcessAffinityMask(GetCurrentProcess(), 0x0);
    QueryPerformanceFrequency(&fq);
    QueryPerformanceCounter(&st);
    LONGLONG begin = GetCycleCount();
	Sleep(sleepTime);
    QueryPerformanceCounter(&ed);
    LONGLONG end = GetCycleCount();
    return (end - begin) * fq.QuadPart / (ed.QuadPart - st.QuadPart);
}
This version seems to work fine. Happy new year, by the way.

Re: Replace QPC to RDTSC Timer in games

Posted: 02 Jan 2022, 00:54
by pox02
wrong
All times are UTC-05:00
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