HostTiming: Pause the hardware clock on pause.

src/common/wall_clock.cpp

@@ -53,6 +53,10 @@ public:
         return Common::Divide128On32(temporary, 1000000000).first;
     }
 
+    void Pause(bool is_paused) override {
+        // Do nothing in this clock type.
+    }
+
 private:
     base_time_point start_time;
 };

src/common/wall_clock.h

@@ -28,6 +28,8 @@ public:
     /// Returns current wall time in emulated cpu cycles
     virtual u64 GetCPUCycles() = 0;
 
+    virtual void Pause(bool is_paused) = 0;
+
     /// Tells if the wall clock, uses the host CPU's hardware clock
     bool IsNative() const {
         return is_native;

src/common/x64/native_clock.cpp

@@ -65,6 +65,13 @@ u64 NativeClock::GetRTSC() {
     return accumulated_ticks;
 }
 
+void NativeClock::Pause(bool is_paused) {
+    if (!is_paused) {
+        _mm_mfence();
+        last_measure = __rdtsc();
+    }
+}
+
 std::chrono::nanoseconds NativeClock::GetTimeNS() {
     const u64 rtsc_value = GetRTSC();
     return std::chrono::nanoseconds{MultiplyAndDivide64(rtsc_value, 1000000000, rtsc_frequency)};

src/common/x64/native_clock.h

@@ -26,6 +26,8 @@ public:
 
     u64 GetCPUCycles() override;
 
+    void Pause(bool is_paused) override;
+
 private:
     u64 GetRTSC();