[core, windows] remove microSleep() and simply wait on events like on linux (#3498)

we shall see if the original code was put there for a reason

or if the microsleeps actually are horrid

Signed-off-by: lizzie <lizzie@eden-emu.dev>

Reviewed-on: https://git.eden-emu.dev/eden-emu/eden/pulls/3498
Reviewed-by: CamilleLaVey <camillelavey99@gmail.com>
Co-authored-by: lizzie <lizzie@eden-emu.dev>
Co-committed-by: lizzie <lizzie@eden-emu.dev>

4 files changed, 3 insertions, 118 deletions

diff --git a/src/common/CMakeLists.txt b/src/common/CMakeLists.txt
index 3d09c1caea..042f5c7bd9 100644
--- a/src/common/CMakeLists.txt
+++ b/src/common/CMakeLists.txt
@@ -1,4 +1,4 @@
-# SPDX-FileCopyrightText: Copyright 2025 Eden Emulator Project
+# SPDX-FileCopyrightText: Copyright 2026 Eden Emulator Project
 # SPDX-License-Identifier: GPL-3.0-or-later
 
 # SPDX-FileCopyrightText: 2018 yuzu Emulator Project SPDX-License-Identifier:
@@ -186,8 +186,6 @@ if(ARCHITECTURE_x86_64)
         common
         PRIVATE x64/cpu_detect.cpp
         x64/cpu_detect.h
-        x64/cpu_wait.cpp
-        x64/cpu_wait.h
         x64/native_clock.cpp
         x64/native_clock.h
         x64/rdtsc.cpp
diff --git a/src/common/x64/cpu_wait.cpp b/src/common/x64/cpu_wait.cpp
deleted file mode 100644
index 12f2e9d4b1..0000000000
--- a/src/common/x64/cpu_wait.cpp
+++ /dev/null
@@ -1,78 +0,0 @@
-// SPDX-FileCopyrightText: Copyright 2025 Eden Emulator Project
-// SPDX-License-Identifier: GPL-3.0-or-later
-
-// SPDX-FileCopyrightText: Copyright 2023 yuzu Emulator Project
-// SPDX-License-Identifier: GPL-2.0-or-later
-
-#include <thread>
-
-#ifdef _MSC_VER
-#include <intrin.h>
-#endif
-
-#include "common/x64/cpu_detect.h"
-#include "common/x64/cpu_wait.h"
-#include "common/x64/rdtsc.h"
-
-namespace Common::X64 {
-
-namespace {
-
-// 100,000 cycles is a reasonable amount of time to wait to save on CPU resources.
-// For reference:
-// At 1 GHz, 100K cycles is 100us
-// At 2 GHz, 100K cycles is 50us
-// At 4 GHz, 100K cycles is 25us
-constexpr auto PauseCycles = 100'000U;
-
-} // Anonymous namespace
-
-#if defined(_MSC_VER) && !defined(__clang__)
-__forceinline static void TPAUSE() {
-    static constexpr auto RequestC02State = 0U;
-    _tpause(RequestC02State, FencedRDTSC() + PauseCycles);
-}
-
-__forceinline static void MWAITX() {
-    static constexpr auto EnableWaitTimeFlag = 1U << 1;
-    static constexpr auto RequestC1State = 0U;
-
-    // monitor_var should be aligned to a cache line.
-    alignas(64) u64 monitor_var{};
-    _mm_monitorx(&monitor_var, 0, 0);
-    _mm_mwaitx(EnableWaitTimeFlag, RequestC1State, PauseCycles);
-}
-#else
-static void TPAUSE() {
-    static constexpr auto RequestC02State = 0U;
-    const auto tsc = FencedRDTSC() + PauseCycles;
-    const auto eax = static_cast<u32>(tsc & 0xFFFFFFFF);
-    const auto edx = static_cast<u32>(tsc >> 32);
-    asm volatile("tpause %0" : : "r"(RequestC02State), "d"(edx), "a"(eax));
-}
-
-static void MWAITX() {
-    static constexpr auto EnableWaitTimeFlag = 1U << 1;
-    static constexpr auto RequestC1State = 0U;
-
-    // monitor_var should be aligned to a cache line.
-    alignas(64) u64 monitor_var{};
-    asm volatile("monitorx" : : "a"(&monitor_var), "c"(0), "d"(0));
-    asm volatile("mwaitx" : : "a"(RequestC1State), "b"(PauseCycles), "c"(EnableWaitTimeFlag));
-}
-#endif
-
-void MicroSleep() {
-    static const bool has_waitpkg = GetCPUCaps().waitpkg;
-    static const bool has_monitorx = GetCPUCaps().monitorx;
-
-    if (has_waitpkg) {
-        TPAUSE();
-    } else if (has_monitorx) {
-        MWAITX();
-    } else {
-        std::this_thread::yield();
-    }
-}
-
-} // namespace Common::X64
diff --git a/src/common/x64/cpu_wait.h b/src/common/x64/cpu_wait.h
deleted file mode 100644
index 99d3757a76..0000000000
--- a/src/common/x64/cpu_wait.h
+++ /dev/null
@@ -1,10 +0,0 @@
-// SPDX-FileCopyrightText: Copyright 2023 yuzu Emulator Project
-// SPDX-License-Identifier: GPL-2.0-or-later
-
-#pragma once
-
-namespace Common::X64 {
-
-void MicroSleep();
-
-} // namespace Common::X64
diff --git a/src/core/core_timing.cpp b/src/core/core_timing.cpp
index 5a582c8cff..b0fa7cd503 100644
--- a/src/core/core_timing.cpp
+++ b/src/core/core_timing.cpp
@@ -1,4 +1,4 @@
-// SPDX-FileCopyrightText: Copyright 2025 Eden Emulator Project
+// SPDX-FileCopyrightText: Copyright 2026 Eden Emulator Project
 // SPDX-License-Identifier: GPL-3.0-or-later
 
 // SPDX-FileCopyrightText: Copyright 2020 yuzu Emulator Project
@@ -13,10 +13,6 @@
 #include "common/windows/timer_resolution.h"
 #endif
 
-#ifdef ARCHITECTURE_x86_64
-#include "common/x64/cpu_wait.h"
-#endif
-
 #include "common/settings.h"
 #include "core/core_timing.h"
 #include "core/hardware_properties.h"
@@ -287,28 +283,7 @@ void CoreTiming::ThreadLoop() {
             if (next_time) {
                 // There are more events left in the queue, wait until the next event.
                 auto wait_time = *next_time - GetGlobalTimeNs().count();
-                if (wait_time > 0) {
-#ifdef _WIN32
-                    while (!paused && !event.IsSet() && wait_time > 0) {
-                        wait_time = *next_time - GetGlobalTimeNs().count();
-                        if (wait_time >= timer_resolution_ns) {
-                            Common::Windows::SleepForOneTick();
-                        } else {
-#ifdef ARCHITECTURE_x86_64
-                            Common::X64::MicroSleep();
-#else
-                            std::this_thread::yield();
-#endif
-                        }
-                    }
-
-                    if (event.IsSet()) {
-                        event.Reset();
-                    }
-#else
-                    event.WaitFor(std::chrono::nanoseconds(wait_time));
-#endif
-                }
+                event.WaitFor(std::chrono::nanoseconds(wait_time));
             } else {
                 // Queue is empty, wait until another event is scheduled and signals us to
                 // continue.