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Merge pull request #99833 from Faless/fix/sleepy_windows_becomes_a_heater

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[Windows] Improve frame pacing by busy waiting as needed
This commit is contained in:
Rémi Verschelde
2024-11-29 22:51:35 +01:00
parent 5125b66871 b57ceefec1
commit f6afacb185
2 changed files with 52 additions and 1 deletions
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50
platform/windows/os_windows.cpp
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@@ -265,7 +265,15 @@ void OS_Windows::initialize() {
// set minimum resolution for periodic timers, otherwise Sleep(n) may wait at least as
// long as the windows scheduler resolution (~16-30ms) even for calls like Sleep(1)
timeBeginPeriod(1);
TIMECAPS time_caps;
if (timeGetDevCaps(&time_caps, sizeof(time_caps)) == MMSYSERR_NOERROR) {
delay_resolution = time_caps.wPeriodMin * 1000;
timeBeginPeriod(time_caps.wPeriodMin);
} else {
ERR_PRINT("Unable to detect sleep timer resolution.");
delay_resolution = 1000;
timeBeginPeriod(1);
}
process_map = memnew((HashMap<ProcessID, ProcessInfo>));
@@ -2223,6 +2231,46 @@ String OS_Windows::get_system_ca_certificates() {
return certs;
}
void OS_Windows::add_frame_delay(bool p_can_draw) {
const uint32_t frame_delay = Engine::get_singleton()->get_frame_delay();
if (frame_delay) {
// Add fixed frame delay to decrease CPU/GPU usage. This doesn't take
// the actual frame time into account.
// Due to the high fluctuation of the actual sleep duration, it's not recommended
// to use this as a FPS limiter.
delay_usec(frame_delay * 1000);
}
// Add a dynamic frame delay to decrease CPU/GPU usage. This takes the
// previous frame time into account for a smoother result.
uint64_t dynamic_delay = 0;
if (is_in_low_processor_usage_mode() || !p_can_draw) {
dynamic_delay = get_low_processor_usage_mode_sleep_usec();
}
const int max_fps = Engine::get_singleton()->get_max_fps();
if (max_fps > 0 && !Engine::get_singleton()->is_editor_hint()) {
// Override the low processor usage mode sleep delay if the target FPS is lower.
dynamic_delay = MAX(dynamic_delay, (uint64_t)(1000000 / max_fps));
}
if (dynamic_delay > 0) {
target_ticks += dynamic_delay;
uint64_t current_ticks = get_ticks_usec();
// The minimum sleep resolution on windows is 1 ms on most systems.
if (current_ticks < (target_ticks - delay_resolution)) {
delay_usec((target_ticks - delay_resolution) - current_ticks);
}
// Busy wait for the remainder of time.
while (get_ticks_usec() < target_ticks) {
YieldProcessor();
}
current_ticks = get_ticks_usec();
target_ticks = MIN(MAX(target_ticks, current_ticks - dynamic_delay), current_ticks + dynamic_delay);
}
}
OS_Windows::OS_Windows(HINSTANCE _hInstance) {
hInstance = _hInstance;

3
platform/windows/os_windows.h
View File

@@ -94,8 +94,10 @@ public:
class JoypadWindows;
class OS_Windows : public OS {
uint64_t target_ticks = 0;
uint64_t ticks_start = 0;
uint64_t ticks_per_second = 0;
uint64_t delay_resolution = 1000;
HINSTANCE hInstance;
MainLoop *main_loop = nullptr;
@@ -188,6 +190,7 @@ public:
virtual Error set_cwd(const String &p_cwd) override;
virtual void add_frame_delay(bool p_can_draw) override;
virtual void delay_usec(uint32_t p_usec) const override;
virtual uint64_t get_ticks_usec() const override;