1ed49f92dd
This utilizes undocumented NtDll functions to change the current timer resolution from the default of 1ms.
88 lines
2.7 KiB
C++
88 lines
2.7 KiB
C++
// SPDX-FileCopyrightText: Copyright 2023 yuzu Emulator Project
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// SPDX-License-Identifier: GPL-2.0-or-later
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#include <windows.h>
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#include "common/windows/timer_resolution.h"
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extern "C" {
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// http://undocumented.ntinternals.net/index.html?page=UserMode%2FUndocumented%20Functions%2FTime%2FNtQueryTimerResolution.html
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NTSYSAPI LONG NTAPI NtQueryTimerResolution(PULONG MinimumResolution, PULONG MaximumResolution,
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PULONG CurrentResolution);
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// http://undocumented.ntinternals.net/index.html?page=UserMode%2FUndocumented%20Functions%2FTime%2FNtSetTimerResolution.html
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NTSYSAPI LONG NTAPI NtSetTimerResolution(ULONG DesiredResolution, BOOLEAN SetResolution,
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PULONG CurrentResolution);
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// http://undocumented.ntinternals.net/index.html?page=UserMode%2FUndocumented%20Functions%2FNT%20Objects%2FThread%2FNtDelayExecution.html
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NTSYSAPI LONG NTAPI NtDelayExecution(BOOLEAN Alertable, PLARGE_INTEGER DelayInterval);
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}
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namespace Common::Windows {
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namespace {
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using namespace std::chrono;
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constexpr nanoseconds ToNS(ULONG hundred_ns) {
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return nanoseconds{hundred_ns * 100};
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}
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constexpr ULONG ToHundredNS(nanoseconds ns) {
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return static_cast<ULONG>(ns.count()) / 100;
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}
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struct TimerResolution {
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std::chrono::nanoseconds minimum;
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std::chrono::nanoseconds maximum;
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std::chrono::nanoseconds current;
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};
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TimerResolution GetTimerResolution() {
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ULONG MinimumTimerResolution;
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ULONG MaximumTimerResolution;
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ULONG CurrentTimerResolution;
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NtQueryTimerResolution(&MinimumTimerResolution, &MaximumTimerResolution,
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&CurrentTimerResolution);
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return {
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.minimum{ToNS(MinimumTimerResolution)},
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.maximum{ToNS(MaximumTimerResolution)},
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.current{ToNS(CurrentTimerResolution)},
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};
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}
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} // Anonymous namespace
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nanoseconds GetMinimumTimerResolution() {
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return GetTimerResolution().minimum;
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}
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nanoseconds GetMaximumTimerResolution() {
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return GetTimerResolution().maximum;
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}
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nanoseconds GetCurrentTimerResolution() {
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return GetTimerResolution().current;
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}
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nanoseconds SetCurrentTimerResolution(nanoseconds timer_resolution) {
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// Set the timer resolution, and return the current timer resolution.
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const auto DesiredTimerResolution = ToHundredNS(timer_resolution);
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ULONG CurrentTimerResolution;
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NtSetTimerResolution(DesiredTimerResolution, TRUE, &CurrentTimerResolution);
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return ToNS(CurrentTimerResolution);
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}
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nanoseconds SetCurrentTimerResolutionToMaximum() {
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return SetCurrentTimerResolution(GetMaximumTimerResolution());
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}
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void SleepForOneTick() {
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LARGE_INTEGER DelayInterval{
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.QuadPart{-1},
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};
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NtDelayExecution(FALSE, &DelayInterval);
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}
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} // namespace Common::Windows
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