6 files changed, 27 insertions, 13 deletions
diff --git a/src/common/x64/cpu_detect.cpp b/src/common/x64/cpu_detect.cpp
index 322aa1f08..1a27532d4 100644
--- a/src/common/x64/cpu_detect.cpp
+++ b/src/common/x64/cpu_detect.cpp
@@ -161,6 +161,22 @@ static CPUCaps Detect() {
         caps.invariant_tsc = Common::Bit<8>(cpu_id[3]);
     }
 
+    if (max_std_fn >= 0x15) {
+        __cpuid(cpu_id, 0x15);
+        caps.tsc_crystal_ratio_denominator = cpu_id[0];
+        caps.tsc_crystal_ratio_numerator = cpu_id[1];
+        caps.crystal_frequency = cpu_id[2];
+        // Some CPU models might not return a crystal frequency.
+        // The CPU model can be detected to use the values from turbostat
+        // https://github.com/torvalds/linux/blob/master/tools/power/x86/turbostat/turbostat.c#L5569
+        // but it's easier to just estimate the TSC tick rate for these cases.
+        if (caps.tsc_crystal_ratio_denominator) {
+            caps.tsc_frequency = static_cast<u64>(caps.crystal_frequency) *
+                                 caps.tsc_crystal_ratio_numerator /
+                                 caps.tsc_crystal_ratio_denominator;
+        }
+    }
+
     if (max_std_fn >= 0x16) {
         __cpuid(cpu_id, 0x16);
         caps.base_frequency = cpu_id[0];
diff --git a/src/common/x64/cpu_detect.h b/src/common/x64/cpu_detect.h
index 9bdc9dbfa..6830f3795 100644
--- a/src/common/x64/cpu_detect.h
+++ b/src/common/x64/cpu_detect.h
@@ -30,6 +30,11 @@ struct CPUCaps {
     u32 max_frequency;
     u32 bus_frequency;
 
+    u32 tsc_crystal_ratio_denominator;
+    u32 tsc_crystal_ratio_numerator;
+    u32 crystal_frequency;
+    u64 tsc_frequency; // Derived from the above three values
+
     bool sse : 1;
     bool sse2 : 1;
     bool sse3 : 1;
diff --git a/src/common/x64/native_clock.cpp b/src/common/x64/native_clock.cpp
index 1b7194503..8b08332ab 100644
--- a/src/common/x64/native_clock.cpp
+++ b/src/common/x64/native_clock.cpp
@@ -89,8 +89,7 @@ u64 NativeClock::GetRTSC() {
         new_time_point.inner.accumulated_ticks = current_time_point.inner.accumulated_ticks + diff;
     } while (!Common::AtomicCompareAndSwap(time_point.pack.data(), new_time_point.pack,
                                            current_time_point.pack, current_time_point.pack));
-    /// The clock cannot be more precise than the guest timer, remove the lower bits
-    return new_time_point.inner.accumulated_ticks & inaccuracy_mask;
+    return new_time_point.inner.accumulated_ticks;
 }
 
 void NativeClock::Pause(bool is_paused) {
diff --git a/src/common/x64/native_clock.h b/src/common/x64/native_clock.h
index 30d2ba2e9..38ae7a462 100644
--- a/src/common/x64/native_clock.h
+++ b/src/common/x64/native_clock.h
@@ -37,12 +37,8 @@ private:
         } inner;
     };
 
-    /// value used to reduce the native clocks accuracy as some apss rely on
-    /// undefined behavior where the level of accuracy in the clock shouldn't
-    /// be higher.
-    static constexpr u64 inaccuracy_mask = ~(UINT64_C(0x400) - 1);
-
     TimePoint time_point;
+
     // factors
     u64 clock_rtsc_factor{};
     u64 cpu_rtsc_factor{};
diff --git a/src/common/x64/xbyak_abi.h b/src/common/x64/xbyak_abi.h
index 87b3d63a4..67e6e63c8 100644
--- a/src/common/x64/xbyak_abi.h
+++ b/src/common/x64/xbyak_abi.h
@@ -1,6 +1,5 @@
-// Copyright 2016 Citra Emulator Project
-// Licensed under GPLv2 or any later version
-// Refer to the license.txt file included.
+// SPDX-FileCopyrightText: 2016 Citra Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
 
 #pragma once
 
diff --git a/src/common/x64/xbyak_util.h b/src/common/x64/xbyak_util.h
index 44d2558f1..250e5cddb 100644
--- a/src/common/x64/xbyak_util.h
+++ b/src/common/x64/xbyak_util.h
@@ -1,6 +1,5 @@
-// Copyright 2016 Citra Emulator Project
-// Licensed under GPLv2 or any later version
-// Refer to the license.txt file included.
+// SPDX-FileCopyrightText: 2016 Citra Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
 
 #pragma once