From 1ed49f92dd56289e6e31a967e602c65ccedd4ff1 Mon Sep 17 00:00:00 2001 From: Morph <39850852+Morph1984@users.noreply.github.com> Date: Wed, 1 Mar 2023 19:27:10 -0500 Subject: [PATCH] common: Implement a method to change the Windows timer resolution This utilizes undocumented NtDll functions to change the current timer resolution from the default of 1ms. --- src/common/CMakeLists.txt | 8 +++ src/common/windows/timer_resolution.cpp | 87 +++++++++++++++++++++++++ src/common/windows/timer_resolution.h | 38 +++++++++++ 3 files changed, 133 insertions(+) create mode 100644 src/common/windows/timer_resolution.cpp create mode 100644 src/common/windows/timer_resolution.h diff --git a/src/common/CMakeLists.txt b/src/common/CMakeLists.txt index 9f5d4c265..58ff5f2f3 100644 --- a/src/common/CMakeLists.txt +++ b/src/common/CMakeLists.txt @@ -144,6 +144,14 @@ add_library(common STATIC zstd_compression.h ) +if (WIN32) + target_sources(common PRIVATE + windows/timer_resolution.cpp + windows/timer_resolution.h + ) + target_link_libraries(common PRIVATE ntdll) +endif() + if(ARCHITECTURE_x86_64) target_sources(common PRIVATE diff --git a/src/common/windows/timer_resolution.cpp b/src/common/windows/timer_resolution.cpp new file mode 100644 index 000000000..6c2063a4c --- /dev/null +++ b/src/common/windows/timer_resolution.cpp @@ -0,0 +1,87 @@ +// SPDX-FileCopyrightText: Copyright 2023 yuzu Emulator Project +// SPDX-License-Identifier: GPL-2.0-or-later + +#include + +#include "common/windows/timer_resolution.h" + +extern "C" { +// http://undocumented.ntinternals.net/index.html?page=UserMode%2FUndocumented%20Functions%2FTime%2FNtQueryTimerResolution.html +NTSYSAPI LONG NTAPI NtQueryTimerResolution(PULONG MinimumResolution, PULONG MaximumResolution, + PULONG CurrentResolution); + +// http://undocumented.ntinternals.net/index.html?page=UserMode%2FUndocumented%20Functions%2FTime%2FNtSetTimerResolution.html +NTSYSAPI LONG NTAPI NtSetTimerResolution(ULONG DesiredResolution, BOOLEAN SetResolution, + PULONG CurrentResolution); + +// http://undocumented.ntinternals.net/index.html?page=UserMode%2FUndocumented%20Functions%2FNT%20Objects%2FThread%2FNtDelayExecution.html +NTSYSAPI LONG NTAPI NtDelayExecution(BOOLEAN Alertable, PLARGE_INTEGER DelayInterval); +} + +namespace Common::Windows { + +namespace { + +using namespace std::chrono; + +constexpr nanoseconds ToNS(ULONG hundred_ns) { + return nanoseconds{hundred_ns * 100}; +} + +constexpr ULONG ToHundredNS(nanoseconds ns) { + return static_cast(ns.count()) / 100; +} + +struct TimerResolution { + std::chrono::nanoseconds minimum; + std::chrono::nanoseconds maximum; + std::chrono::nanoseconds current; +}; + +TimerResolution GetTimerResolution() { + ULONG MinimumTimerResolution; + ULONG MaximumTimerResolution; + ULONG CurrentTimerResolution; + NtQueryTimerResolution(&MinimumTimerResolution, &MaximumTimerResolution, + &CurrentTimerResolution); + return { + .minimum{ToNS(MinimumTimerResolution)}, + .maximum{ToNS(MaximumTimerResolution)}, + .current{ToNS(CurrentTimerResolution)}, + }; +} + +} // Anonymous namespace + +nanoseconds GetMinimumTimerResolution() { + return GetTimerResolution().minimum; +} + +nanoseconds GetMaximumTimerResolution() { + return GetTimerResolution().maximum; +} + +nanoseconds GetCurrentTimerResolution() { + return GetTimerResolution().current; +} + +nanoseconds SetCurrentTimerResolution(nanoseconds timer_resolution) { + // Set the timer resolution, and return the current timer resolution. + const auto DesiredTimerResolution = ToHundredNS(timer_resolution); + ULONG CurrentTimerResolution; + NtSetTimerResolution(DesiredTimerResolution, TRUE, &CurrentTimerResolution); + return ToNS(CurrentTimerResolution); +} + +nanoseconds SetCurrentTimerResolutionToMaximum() { + return SetCurrentTimerResolution(GetMaximumTimerResolution()); +} + +void SleepForOneTick() { + LARGE_INTEGER DelayInterval{ + .QuadPart{-1}, + }; + NtDelayExecution(FALSE, &DelayInterval); +} + +} // namespace Common::Windows diff --git a/src/common/windows/timer_resolution.h b/src/common/windows/timer_resolution.h new file mode 100644 index 000000000..e1e50a62d --- /dev/null +++ b/src/common/windows/timer_resolution.h @@ -0,0 +1,38 @@ +// SPDX-FileCopyrightText: Copyright 2023 yuzu Emulator Project +// SPDX-License-Identifier: GPL-2.0-or-later + +#pragma once + +#include + +namespace Common::Windows { + +/// Returns the minimum (least precise) supported timer resolution in nanoseconds. +std::chrono::nanoseconds GetMinimumTimerResolution(); + +/// Returns the maximum (most precise) supported timer resolution in nanoseconds. +std::chrono::nanoseconds GetMaximumTimerResolution(); + +/// Returns the current timer resolution in nanoseconds. +std::chrono::nanoseconds GetCurrentTimerResolution(); + +/** + * Sets the current timer resolution. + * + * @param timer_resolution Timer resolution in nanoseconds. + * + * @returns The current timer resolution. + */ +std::chrono::nanoseconds SetCurrentTimerResolution(std::chrono::nanoseconds timer_resolution); + +/** + * Sets the current timer resolution to the maximum supported timer resolution. + * + * @returns The current timer resolution. + */ +std::chrono::nanoseconds SetCurrentTimerResolutionToMaximum(); + +/// Sleep for one tick of the current timer resolution. +void SleepForOneTick(); + +} // namespace Common::Windows