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authorbunnei <bunneidev@gmail.com>2021-01-16 08:01:42 +0100
committerGitHub <noreply@github.com>2021-01-16 08:01:42 +0100
commita7fd61fcce4634b8e849ab65a732080e77fad902 (patch)
tree843fb62264d5acf24a243d564de7492be660fa2e
parentMerge pull request #5336 from lioncash/tree (diff)
parentX86/NativeClock: Reimplement RTDSC access to be lock free. (diff)
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-rw-r--r--src/common/CMakeLists.txt1
-rw-r--r--src/common/atomic_ops.cpp75
-rw-r--r--src/common/atomic_ops.h71
-rw-r--r--src/common/x64/native_clock.cpp110
-rw-r--r--src/common/x64/native_clock.h21
5 files changed, 174 insertions, 104 deletions
diff --git a/src/common/CMakeLists.txt b/src/common/CMakeLists.txt
index 9824c5564..f77575a00 100644
--- a/src/common/CMakeLists.txt
+++ b/src/common/CMakeLists.txt
@@ -98,7 +98,6 @@ add_library(common STATIC
algorithm.h
alignment.h
assert.h
- atomic_ops.cpp
atomic_ops.h
detached_tasks.cpp
detached_tasks.h
diff --git a/src/common/atomic_ops.cpp b/src/common/atomic_ops.cpp
deleted file mode 100644
index 1612d0e67..000000000
--- a/src/common/atomic_ops.cpp
+++ /dev/null
@@ -1,75 +0,0 @@
-// Copyright 2020 yuzu Emulator Project
-// Licensed under GPLv2 or any later version
-// Refer to the license.txt file included.
-
-#include <cstring>
-
-#include "common/atomic_ops.h"
-
-#if _MSC_VER
-#include <intrin.h>
-#endif
-
-namespace Common {
-
-#if _MSC_VER
-
-bool AtomicCompareAndSwap(volatile u8* pointer, u8 value, u8 expected) {
- const u8 result =
- _InterlockedCompareExchange8(reinterpret_cast<volatile char*>(pointer), value, expected);
- return result == expected;
-}
-
-bool AtomicCompareAndSwap(volatile u16* pointer, u16 value, u16 expected) {
- const u16 result =
- _InterlockedCompareExchange16(reinterpret_cast<volatile short*>(pointer), value, expected);
- return result == expected;
-}
-
-bool AtomicCompareAndSwap(volatile u32* pointer, u32 value, u32 expected) {
- const u32 result =
- _InterlockedCompareExchange(reinterpret_cast<volatile long*>(pointer), value, expected);
- return result == expected;
-}
-
-bool AtomicCompareAndSwap(volatile u64* pointer, u64 value, u64 expected) {
- const u64 result = _InterlockedCompareExchange64(reinterpret_cast<volatile __int64*>(pointer),
- value, expected);
- return result == expected;
-}
-
-bool AtomicCompareAndSwap(volatile u64* pointer, u128 value, u128 expected) {
- return _InterlockedCompareExchange128(reinterpret_cast<volatile __int64*>(pointer), value[1],
- value[0],
- reinterpret_cast<__int64*>(expected.data())) != 0;
-}
-
-#else
-
-bool AtomicCompareAndSwap(volatile u8* pointer, u8 value, u8 expected) {
- return __sync_bool_compare_and_swap(pointer, expected, value);
-}
-
-bool AtomicCompareAndSwap(volatile u16* pointer, u16 value, u16 expected) {
- return __sync_bool_compare_and_swap(pointer, expected, value);
-}
-
-bool AtomicCompareAndSwap(volatile u32* pointer, u32 value, u32 expected) {
- return __sync_bool_compare_and_swap(pointer, expected, value);
-}
-
-bool AtomicCompareAndSwap(volatile u64* pointer, u64 value, u64 expected) {
- return __sync_bool_compare_and_swap(pointer, expected, value);
-}
-
-bool AtomicCompareAndSwap(volatile u64* pointer, u128 value, u128 expected) {
- unsigned __int128 value_a;
- unsigned __int128 expected_a;
- std::memcpy(&value_a, value.data(), sizeof(u128));
- std::memcpy(&expected_a, expected.data(), sizeof(u128));
- return __sync_bool_compare_and_swap((unsigned __int128*)pointer, expected_a, value_a);
-}
-
-#endif
-
-} // namespace Common
diff --git a/src/common/atomic_ops.h b/src/common/atomic_ops.h
index b46888589..2b1f515e8 100644
--- a/src/common/atomic_ops.h
+++ b/src/common/atomic_ops.h
@@ -4,14 +4,75 @@
#pragma once
+#include <cstring>
+#include <memory>
+
#include "common/common_types.h"
+#if _MSC_VER
+#include <intrin.h>
+#endif
+
namespace Common {
-[[nodiscard]] bool AtomicCompareAndSwap(volatile u8* pointer, u8 value, u8 expected);
-[[nodiscard]] bool AtomicCompareAndSwap(volatile u16* pointer, u16 value, u16 expected);
-[[nodiscard]] bool AtomicCompareAndSwap(volatile u32* pointer, u32 value, u32 expected);
-[[nodiscard]] bool AtomicCompareAndSwap(volatile u64* pointer, u64 value, u64 expected);
-[[nodiscard]] bool AtomicCompareAndSwap(volatile u64* pointer, u128 value, u128 expected);
+#if _MSC_VER
+
+[[nodiscard]] inline bool AtomicCompareAndSwap(volatile u8* pointer, u8 value, u8 expected) {
+ const u8 result =
+ _InterlockedCompareExchange8(reinterpret_cast<volatile char*>(pointer), value, expected);
+ return result == expected;
+}
+
+[[nodiscard]] inline bool AtomicCompareAndSwap(volatile u16* pointer, u16 value, u16 expected) {
+ const u16 result =
+ _InterlockedCompareExchange16(reinterpret_cast<volatile short*>(pointer), value, expected);
+ return result == expected;
+}
+
+[[nodiscard]] inline bool AtomicCompareAndSwap(volatile u32* pointer, u32 value, u32 expected) {
+ const u32 result =
+ _InterlockedCompareExchange(reinterpret_cast<volatile long*>(pointer), value, expected);
+ return result == expected;
+}
+
+[[nodiscard]] inline bool AtomicCompareAndSwap(volatile u64* pointer, u64 value, u64 expected) {
+ const u64 result = _InterlockedCompareExchange64(reinterpret_cast<volatile __int64*>(pointer),
+ value, expected);
+ return result == expected;
+}
+
+[[nodiscard]] inline bool AtomicCompareAndSwap(volatile u64* pointer, u128 value, u128 expected) {
+ return _InterlockedCompareExchange128(reinterpret_cast<volatile __int64*>(pointer), value[1],
+ value[0],
+ reinterpret_cast<__int64*>(expected.data())) != 0;
+}
+
+#else
+
+[[nodiscard]] inline bool AtomicCompareAndSwap(volatile u8* pointer, u8 value, u8 expected) {
+ return __sync_bool_compare_and_swap(pointer, expected, value);
+}
+
+[[nodiscard]] inline bool AtomicCompareAndSwap(volatile u16* pointer, u16 value, u16 expected) {
+ return __sync_bool_compare_and_swap(pointer, expected, value);
+}
+
+[[nodiscard]] inline bool AtomicCompareAndSwap(volatile u32* pointer, u32 value, u32 expected) {
+ return __sync_bool_compare_and_swap(pointer, expected, value);
+}
+
+[[nodiscard]] inline bool AtomicCompareAndSwap(volatile u64* pointer, u64 value, u64 expected) {
+ return __sync_bool_compare_and_swap(pointer, expected, value);
+}
+
+[[nodiscard]] inline bool AtomicCompareAndSwap(volatile u64* pointer, u128 value, u128 expected) {
+ unsigned __int128 value_a;
+ unsigned __int128 expected_a;
+ std::memcpy(&value_a, value.data(), sizeof(u128));
+ std::memcpy(&expected_a, expected.data(), sizeof(u128));
+ return __sync_bool_compare_and_swap((unsigned __int128*)pointer, expected_a, value_a);
+}
+
+#endif
} // namespace Common
diff --git a/src/common/x64/native_clock.cpp b/src/common/x64/native_clock.cpp
index eb8a7782f..a65f6b832 100644
--- a/src/common/x64/native_clock.cpp
+++ b/src/common/x64/native_clock.cpp
@@ -2,19 +2,74 @@
// Licensed under GPLv2 or any later version
// Refer to the license.txt file included.
+#include <array>
#include <chrono>
+#include <limits>
#include <mutex>
#include <thread>
#ifdef _MSC_VER
#include <intrin.h>
+
+#pragma intrinsic(__umulh)
+#pragma intrinsic(_udiv128)
#else
#include <x86intrin.h>
#endif
+#include "common/atomic_ops.h"
#include "common/uint128.h"
#include "common/x64/native_clock.h"
+namespace {
+
+[[nodiscard]] u64 GetFixedPoint64Factor(u64 numerator, u64 divisor) {
+#ifdef __SIZEOF_INT128__
+ const auto base = static_cast<unsigned __int128>(numerator) << 64ULL;
+ return static_cast<u64>(base / divisor);
+#elif defined(_M_X64) || defined(_M_ARM64)
+ std::array<u64, 2> r = {0, numerator};
+ u64 remainder;
+#if _MSC_VER < 1923
+ return udiv128(r[1], r[0], divisor, &remainder);
+#else
+ return _udiv128(r[1], r[0], divisor, &remainder);
+#endif
+#else
+ // This one is bit more inaccurate.
+ return MultiplyAndDivide64(std::numeric_limits<u64>::max(), numerator, divisor);
+#endif
+}
+
+[[nodiscard]] u64 MultiplyHigh(u64 a, u64 b) {
+#ifdef __SIZEOF_INT128__
+ return (static_cast<unsigned __int128>(a) * static_cast<unsigned __int128>(b)) >> 64;
+#elif defined(_M_X64) || defined(_M_ARM64)
+ return __umulh(a, b); // MSVC
+#else
+ // Generic fallback
+ const u64 a_lo = u32(a);
+ const u64 a_hi = a >> 32;
+ const u64 b_lo = u32(b);
+ const u64 b_hi = b >> 32;
+
+ const u64 a_x_b_hi = a_hi * b_hi;
+ const u64 a_x_b_mid = a_hi * b_lo;
+ const u64 b_x_a_mid = b_hi * a_lo;
+ const u64 a_x_b_lo = a_lo * b_lo;
+
+ const u64 carry_bit = (static_cast<u64>(static_cast<u32>(a_x_b_mid)) +
+ static_cast<u64>(static_cast<u32>(b_x_a_mid)) + (a_x_b_lo >> 32)) >>
+ 32;
+
+ const u64 multhi = a_x_b_hi + (a_x_b_mid >> 32) + (b_x_a_mid >> 32) + carry_bit;
+
+ return multhi;
+#endif
+}
+
+} // namespace
+
namespace Common {
u64 EstimateRDTSCFrequency() {
@@ -48,54 +103,71 @@ NativeClock::NativeClock(u64 emulated_cpu_frequency_, u64 emulated_clock_frequen
: WallClock(emulated_cpu_frequency_, emulated_clock_frequency_, true), rtsc_frequency{
rtsc_frequency_} {
_mm_mfence();
- last_measure = __rdtsc();
- accumulated_ticks = 0U;
+ time_point.inner.last_measure = __rdtsc();
+ time_point.inner.accumulated_ticks = 0U;
+ ns_rtsc_factor = GetFixedPoint64Factor(1000000000, rtsc_frequency);
+ us_rtsc_factor = GetFixedPoint64Factor(1000000, rtsc_frequency);
+ ms_rtsc_factor = GetFixedPoint64Factor(1000, rtsc_frequency);
+ clock_rtsc_factor = GetFixedPoint64Factor(emulated_clock_frequency, rtsc_frequency);
+ cpu_rtsc_factor = GetFixedPoint64Factor(emulated_cpu_frequency, rtsc_frequency);
}
u64 NativeClock::GetRTSC() {
- std::scoped_lock scope{rtsc_serialize};
- _mm_mfence();
- const u64 current_measure = __rdtsc();
- u64 diff = current_measure - last_measure;
- diff = diff & ~static_cast<u64>(static_cast<s64>(diff) >> 63); // max(diff, 0)
- if (current_measure > last_measure) {
- last_measure = current_measure;
- }
- accumulated_ticks += diff;
+ TimePoint new_time_point{};
+ TimePoint current_time_point{};
+ do {
+ current_time_point.pack = time_point.pack;
+ _mm_mfence();
+ const u64 current_measure = __rdtsc();
+ u64 diff = current_measure - current_time_point.inner.last_measure;
+ diff = diff & ~static_cast<u64>(static_cast<s64>(diff) >> 63); // max(diff, 0)
+ new_time_point.inner.last_measure = current_measure > current_time_point.inner.last_measure
+ ? current_measure
+ : current_time_point.inner.last_measure;
+ 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));
/// The clock cannot be more precise than the guest timer, remove the lower bits
- return accumulated_ticks & inaccuracy_mask;
+ return new_time_point.inner.accumulated_ticks & inaccuracy_mask;
}
void NativeClock::Pause(bool is_paused) {
if (!is_paused) {
- _mm_mfence();
- last_measure = __rdtsc();
+ TimePoint current_time_point{};
+ TimePoint new_time_point{};
+ do {
+ current_time_point.pack = time_point.pack;
+ new_time_point.pack = current_time_point.pack;
+ _mm_mfence();
+ new_time_point.inner.last_measure = __rdtsc();
+ } while (!Common::AtomicCompareAndSwap(time_point.pack.data(), new_time_point.pack,
+ current_time_point.pack));
}
}
std::chrono::nanoseconds NativeClock::GetTimeNS() {
const u64 rtsc_value = GetRTSC();
- return std::chrono::nanoseconds{MultiplyAndDivide64(rtsc_value, 1000000000, rtsc_frequency)};
+ return std::chrono::nanoseconds{MultiplyHigh(rtsc_value, ns_rtsc_factor)};
}
std::chrono::microseconds NativeClock::GetTimeUS() {
const u64 rtsc_value = GetRTSC();
- return std::chrono::microseconds{MultiplyAndDivide64(rtsc_value, 1000000, rtsc_frequency)};
+ return std::chrono::microseconds{MultiplyHigh(rtsc_value, us_rtsc_factor)};
}
std::chrono::milliseconds NativeClock::GetTimeMS() {
const u64 rtsc_value = GetRTSC();
- return std::chrono::milliseconds{MultiplyAndDivide64(rtsc_value, 1000, rtsc_frequency)};
+ return std::chrono::milliseconds{MultiplyHigh(rtsc_value, ms_rtsc_factor)};
}
u64 NativeClock::GetClockCycles() {
const u64 rtsc_value = GetRTSC();
- return MultiplyAndDivide64(rtsc_value, emulated_clock_frequency, rtsc_frequency);
+ return MultiplyHigh(rtsc_value, clock_rtsc_factor);
}
u64 NativeClock::GetCPUCycles() {
const u64 rtsc_value = GetRTSC();
- return MultiplyAndDivide64(rtsc_value, emulated_cpu_frequency, rtsc_frequency);
+ return MultiplyHigh(rtsc_value, cpu_rtsc_factor);
}
} // namespace X64
diff --git a/src/common/x64/native_clock.h b/src/common/x64/native_clock.h
index 6d1e32ac8..7cbd400d2 100644
--- a/src/common/x64/native_clock.h
+++ b/src/common/x64/native_clock.h
@@ -6,7 +6,6 @@
#include <optional>
-#include "common/spin_lock.h"
#include "common/wall_clock.h"
namespace Common {
@@ -32,14 +31,28 @@ public:
private:
u64 GetRTSC();
+ union alignas(16) TimePoint {
+ TimePoint() : pack{} {}
+ u128 pack{};
+ struct Inner {
+ u64 last_measure{};
+ u64 accumulated_ticks{};
+ } 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);
- SpinLock rtsc_serialize{};
- u64 last_measure{};
- u64 accumulated_ticks{};
+ TimePoint time_point;
+ // factors
+ u64 clock_rtsc_factor{};
+ u64 cpu_rtsc_factor{};
+ u64 ns_rtsc_factor{};
+ u64 us_rtsc_factor{};
+ u64 ms_rtsc_factor{};
+
u64 rtsc_frequency;
};
} // namespace X64