Merge pull request #99178 from mrsaturnsan/windows_sleep_precision

Make `delay_usec` more precise on Windows to fix framepacing
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Thaddeus Crews 2024-11-18 09:23:50 -06:00
commit 449d90b64e
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@ -817,10 +817,22 @@ double OS_Windows::get_unix_time() const {
}
void OS_Windows::delay_usec(uint32_t p_usec) const {
if (p_usec < 1000) {
Sleep(1);
} else {
Sleep(p_usec / 1000);
constexpr uint32_t tolerance = 1000 + 20;
uint64_t t0 = get_ticks_usec();
uint64_t target_time = t0 + p_usec;
// Calculate sleep duration with a tolerance for fine-tuning.
if (p_usec > tolerance) {
uint32_t coarse_sleep_usec = p_usec - tolerance;
if (coarse_sleep_usec >= 1000) {
Sleep(coarse_sleep_usec / 1000);
}
}
// Spin-wait until we reach the precise target time.
while (get_ticks_usec() < target_time) {
YieldProcessor();
}
}