diff options
Diffstat (limited to 'src/common/x64/native_clock.cpp')
| -rw-r--r-- | src/common/x64/native_clock.cpp | 59 |
1 files changed, 41 insertions, 18 deletions
diff --git a/src/common/x64/native_clock.cpp b/src/common/x64/native_clock.cpp index 347e41efc..7fd9d22f8 100644 --- a/src/common/x64/native_clock.cpp +++ b/src/common/x64/native_clock.cpp @@ -10,25 +10,49 @@ #include "common/uint128.h" #include "common/x64/native_clock.h" +#ifdef _MSC_VER +#include <intrin.h> +#endif + namespace Common { +#ifdef _MSC_VER +__forceinline static u64 FencedRDTSC() { + _mm_lfence(); + _ReadWriteBarrier(); + const u64 result = __rdtsc(); + _mm_lfence(); + _ReadWriteBarrier(); + return result; +} +#else +static u64 FencedRDTSC() { + u64 result; + asm volatile("lfence\n\t" + "rdtsc\n\t" + "shl $32, %%rdx\n\t" + "or %%rdx, %0\n\t" + "lfence" + : "=a"(result) + : + : "rdx", "memory", "cc"); + return result; +} +#endif + u64 EstimateRDTSCFrequency() { // Discard the first result measuring the rdtsc. - _mm_mfence(); - __rdtsc(); + FencedRDTSC(); std::this_thread::sleep_for(std::chrono::milliseconds{1}); - _mm_mfence(); - __rdtsc(); + FencedRDTSC(); // Get the current time. const auto start_time = std::chrono::steady_clock::now(); - _mm_mfence(); - const u64 tsc_start = __rdtsc(); + const u64 tsc_start = FencedRDTSC(); // Wait for 200 milliseconds. std::this_thread::sleep_for(std::chrono::milliseconds{200}); const auto end_time = std::chrono::steady_clock::now(); - _mm_mfence(); - const u64 tsc_end = __rdtsc(); + const u64 tsc_end = FencedRDTSC(); // Calculate differences. const u64 timer_diff = static_cast<u64>( std::chrono::duration_cast<std::chrono::nanoseconds>(end_time - start_time).count()); @@ -42,8 +66,7 @@ NativeClock::NativeClock(u64 emulated_cpu_frequency_, u64 emulated_clock_frequen u64 rtsc_frequency_) : WallClock(emulated_cpu_frequency_, emulated_clock_frequency_, true), rtsc_frequency{ rtsc_frequency_} { - _mm_mfence(); - time_point.inner.last_measure = __rdtsc(); + time_point.inner.last_measure = FencedRDTSC(); time_point.inner.accumulated_ticks = 0U; ns_rtsc_factor = GetFixedPoint64Factor(NS_RATIO, rtsc_frequency); us_rtsc_factor = GetFixedPoint64Factor(US_RATIO, rtsc_frequency); @@ -55,10 +78,10 @@ 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(); + const u64 current_measure = FencedRDTSC(); 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 @@ -66,7 +89,7 @@ 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 +98,13 @@ 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(); + new_time_point.inner.last_measure = FencedRDTSC(); } while (!Common::AtomicCompareAndSwap(time_point.pack.data(), new_time_point.pack, - current_time_point.pack)); + current_time_point.pack, current_time_point.pack)); } } |