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-rw-r--r--src/common/x64/native_clock.cpp51
-rw-r--r--src/common/x64/native_clock.h5
2 files changed, 46 insertions, 10 deletions
diff --git a/src/common/x64/native_clock.cpp b/src/common/x64/native_clock.cpp
index 8b08332ab..76c66e7ee 100644
--- a/src/common/x64/native_clock.cpp
+++ b/src/common/x64/native_clock.cpp
@@ -6,6 +6,7 @@
#include <thread>
#include "common/atomic_ops.h"
+#include "common/steady_clock.h"
#include "common/uint128.h"
#include "common/x64/native_clock.h"
@@ -39,6 +40,12 @@ static u64 FencedRDTSC() {
}
#endif
+template <u64 Nearest>
+static u64 RoundToNearest(u64 value) {
+ const auto mod = value % Nearest;
+ return mod >= (Nearest / 2) ? (value - mod + Nearest) : (value - mod);
+}
+
u64 EstimateRDTSCFrequency() {
// Discard the first result measuring the rdtsc.
FencedRDTSC();
@@ -46,18 +53,18 @@ u64 EstimateRDTSCFrequency() {
FencedRDTSC();
// Get the current time.
- const auto start_time = std::chrono::steady_clock::now();
+ const auto start_time = Common::RealTimeClock::Now();
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();
+ // Wait for 250 milliseconds.
+ std::this_thread::sleep_for(std::chrono::milliseconds{250});
+ const auto end_time = Common::RealTimeClock::Now();
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());
const u64 tsc_diff = tsc_end - tsc_start;
const u64 tsc_freq = MultiplyAndDivide64(tsc_diff, 1000000000ULL, timer_diff);
- return tsc_freq;
+ return RoundToNearest<1000>(tsc_freq);
}
namespace X64 {
@@ -65,13 +72,29 @@ 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_} {
+ // Thread to re-adjust the RDTSC frequency after 10 seconds has elapsed.
+ time_sync_thread = std::jthread{[this](std::stop_token token) {
+ // Get the current time.
+ const auto start_time = Common::RealTimeClock::Now();
+ const u64 tsc_start = FencedRDTSC();
+ // Wait for 10 seconds.
+ if (!Common::StoppableTimedWait(token, std::chrono::seconds{10})) {
+ return;
+ }
+ const auto end_time = Common::RealTimeClock::Now();
+ 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());
+ const u64 tsc_diff = tsc_end - tsc_start;
+ const u64 tsc_freq = MultiplyAndDivide64(tsc_diff, 1000000000ULL, timer_diff);
+ rtsc_frequency = tsc_freq;
+ CalculateAndSetFactors();
+ }};
+
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);
- ms_rtsc_factor = GetFixedPoint64Factor(MS_RATIO, rtsc_frequency);
- clock_rtsc_factor = GetFixedPoint64Factor(emulated_clock_frequency, rtsc_frequency);
- cpu_rtsc_factor = GetFixedPoint64Factor(emulated_cpu_frequency, rtsc_frequency);
+ CalculateAndSetFactors();
}
u64 NativeClock::GetRTSC() {
@@ -131,6 +154,14 @@ u64 NativeClock::GetCPUCycles() {
return MultiplyHigh(rtsc_value, cpu_rtsc_factor);
}
+void NativeClock::CalculateAndSetFactors() {
+ ns_rtsc_factor = GetFixedPoint64Factor(NS_RATIO, rtsc_frequency);
+ us_rtsc_factor = GetFixedPoint64Factor(US_RATIO, rtsc_frequency);
+ ms_rtsc_factor = GetFixedPoint64Factor(MS_RATIO, rtsc_frequency);
+ clock_rtsc_factor = GetFixedPoint64Factor(emulated_clock_frequency, rtsc_frequency);
+ cpu_rtsc_factor = GetFixedPoint64Factor(emulated_cpu_frequency, rtsc_frequency);
+}
+
} // namespace X64
} // namespace Common
diff --git a/src/common/x64/native_clock.h b/src/common/x64/native_clock.h
index 38ae7a462..03ca291d8 100644
--- a/src/common/x64/native_clock.h
+++ b/src/common/x64/native_clock.h
@@ -3,6 +3,7 @@
#pragma once
+#include "common/polyfill_thread.h"
#include "common/wall_clock.h"
namespace Common {
@@ -28,6 +29,8 @@ public:
private:
u64 GetRTSC();
+ void CalculateAndSetFactors();
+
union alignas(16) TimePoint {
TimePoint() : pack{} {}
u128 pack{};
@@ -47,6 +50,8 @@ private:
u64 ms_rtsc_factor{};
u64 rtsc_frequency;
+
+ std::jthread time_sync_thread;
};
} // namespace X64