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Merge pull request #8105 from merryhime/atomicload128

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native_clock: Use AtomicLoad128
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bunnei 2022-04-03 14:26:28 -07:00 committed by GitHub
commit e9cf2d43f1
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GPG key ID: 4AEE18F83AFDEB23
2 changed files with 96 additions and 4 deletions
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90
src/common/atomic_ops.h
View file

@ -46,6 +46,50 @@ namespace Common {
reinterpret_cast<__int64*>(expected.data())) != 0;
}
[[nodiscard]] inline bool AtomicCompareAndSwap(volatile u8* pointer, u8 value, u8 expected,
u8& actual) {
actual =
_InterlockedCompareExchange8(reinterpret_cast<volatile char*>(pointer), value, expected);
return actual == expected;
}
[[nodiscard]] inline bool AtomicCompareAndSwap(volatile u16* pointer, u16 value, u16 expected,
u16& actual) {
actual =
_InterlockedCompareExchange16(reinterpret_cast<volatile short*>(pointer), value, expected);
return actual == expected;
}
[[nodiscard]] inline bool AtomicCompareAndSwap(volatile u32* pointer, u32 value, u32 expected,
u32& actual) {
actual =
_InterlockedCompareExchange(reinterpret_cast<volatile long*>(pointer), value, expected);
return actual == expected;
}
[[nodiscard]] inline bool AtomicCompareAndSwap(volatile u64* pointer, u64 value, u64 expected,
u64& actual) {
actual = _InterlockedCompareExchange64(reinterpret_cast<volatile __int64*>(pointer), value,
expected);
return actual == expected;
}
[[nodiscard]] inline bool AtomicCompareAndSwap(volatile u64* pointer, u128 value, u128 expected,
u128& actual) {
const bool result =
_InterlockedCompareExchange128(reinterpret_cast<volatile __int64*>(pointer), value[1],
value[0], reinterpret_cast<__int64*>(expected.data())) != 0;
actual = expected;
return result;
}
[[nodiscard]] inline u128 AtomicLoad128(volatile u64* pointer) {
u128 result{};
_InterlockedCompareExchange128(reinterpret_cast<volatile __int64*>(pointer), result[1],
result[0], reinterpret_cast<__int64*>(result.data()));
return result;
}
#else
[[nodiscard]] inline bool AtomicCompareAndSwap(volatile u8* pointer, u8 value, u8 expected) {
@ -72,6 +116,52 @@ namespace Common {
return __sync_bool_compare_and_swap((unsigned __int128*)pointer, expected_a, value_a);
}
[[nodiscard]] inline bool AtomicCompareAndSwap(volatile u8* pointer, u8 value, u8 expected,
u8& actual) {
actual = __sync_val_compare_and_swap(pointer, expected, value);
return actual == expected;
}
[[nodiscard]] inline bool AtomicCompareAndSwap(volatile u16* pointer, u16 value, u16 expected,
u16& actual) {
actual = __sync_val_compare_and_swap(pointer, expected, value);
return actual == expected;
}
[[nodiscard]] inline bool AtomicCompareAndSwap(volatile u32* pointer, u32 value, u32 expected,
u32& actual) {
actual = __sync_val_compare_and_swap(pointer, expected, value);
return actual == expected;
}
[[nodiscard]] inline bool AtomicCompareAndSwap(volatile u64* pointer, u64 value, u64 expected,
u64& actual) {
actual = __sync_val_compare_and_swap(pointer, expected, value);
return actual == expected;
}
[[nodiscard]] inline bool AtomicCompareAndSwap(volatile u64* pointer, u128 value, u128 expected,
u128& actual) {
unsigned __int128 value_a;
unsigned __int128 expected_a;
unsigned __int128 actual_a;
std::memcpy(&value_a, value.data(), sizeof(u128));
std::memcpy(&expected_a, expected.data(), sizeof(u128));
actual_a = __sync_val_compare_and_swap((unsigned __int128*)pointer, expected_a, value_a);
std::memcpy(actual.data(), &actual_a, sizeof(u128));
return actual_a == expected_a;
}
[[nodiscard]] inline u128 AtomicLoad128(volatile u64* pointer) {
unsigned __int128 zeros_a = 0;
unsigned __int128 result_a =
__sync_val_compare_and_swap((unsigned __int128*)pointer, zeros_a, zeros_a);
u128 result;
std::memcpy(result.data(), &result_a, sizeof(u128));
return result;
}
#endif
} // namespace Common

10
src/common/x64/native_clock.cpp
View file

@ -55,8 +55,9 @@ NativeClock::NativeClock(u64 emulated_cpu_frequency_, u64 emulated_clock_frequen
u64 NativeClock::GetRTSC() {
TimePoint new_time_point{};
TimePoint current_time_point{};
current_time_point.pack = Common::AtomicLoad128(time_point.pack.data());
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;
@ -66,7 +67,7 @@ u64 NativeClock::GetRTSC() {
: 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));
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;
}
@ -75,13 +76,14 @@ void NativeClock::Pause(bool is_paused) {
if (!is_paused) {
TimePoint current_time_point{};
TimePoint new_time_point{};
current_time_point.pack = Common::AtomicLoad128(time_point.pack.data());
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));
current_time_point.pack, current_time_point.pack));
}
}