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@ngryman

ngryman/usleep.c

Created September 8, 2013 07:07
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usleep for Windows.
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usleep.c
void usleep(DWORD waitTime){
LARGE_INTEGER perfCnt, start, now;
QueryPerformanceFrequency(&perfCnt);
QueryPerformanceCounter(&start);
do {
QueryPerformanceCounter((LARGE_INTEGER*) &now);
} while ((now.QuadPart - start.QuadPart) / float(perfCnt.QuadPart) * 1000 * 1000 < waitTime);
}
@cidzoo
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cidzoo commented Dec 5, 2018

Caution: this gist snippet from @ngryman will do busy waiting, it may not be what you want!

Can't agree more with @latsa, and thanks for the much more efficient plain Win32 API version.

@DanielGibson
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DanielGibson commented Jan 26, 2023 •
edited

With @latsa's solutions (at least std::this_thread::sleep_for() and WaitForSingleObject(), I'm not using boost), even usleep(1) takes at least 10-15ms or so on my Win10 machine, which makes microsecond granularity kinda pointless..
Calling timeBeginPeriod(1); at the beginning of the program makes Sleep(1) take about 2ms instead of 15ms; with the WaitForSingleObject() method I can even get down to 1ms, but not below.

The busy waiting can be made a bit more CPU-friendly by inserting calls to _mm_pause() (that won't decrease the CPU usage that the task manager shows, but the CPU will run at a slighly lower temperature, or at least it did on my machine when inserting like 20 calls to _mm_pause() in between calls to QueryPerformanceCounter())

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