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Merge pull request #7809 from Morph1984/clock-constants

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common: wall_clock: Utilize constants for ms, us, and ns ratios
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bunnei 2022-02-01 18:34:31 -07:00 committed by GitHub
commit 50e9ba34b4
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3 changed files with 19 additions and 11 deletions
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16
src/common/wall_clock.cpp
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@ -65,16 +65,20 @@ private:
#ifdef ARCHITECTURE_x86_64
std::unique_ptr<WallClock> CreateBestMatchingClock(u32 emulated_cpu_frequency,
u32 emulated_clock_frequency) {
std::unique_ptr<WallClock> CreateBestMatchingClock(u64 emulated_cpu_frequency,
u64 emulated_clock_frequency) {
const auto& caps = GetCPUCaps();
u64 rtsc_frequency = 0;
if (caps.invariant_tsc) {
rtsc_frequency = EstimateRDTSCFrequency();
}
// Fallback to StandardWallClock if rtsc period is higher than a nano second
if (rtsc_frequency <= 1000000000) {
// Fallback to StandardWallClock if the hardware TSC does not have the precision greater than:
// - A nanosecond
// - The emulated CPU frequency
// - The emulated clock counter frequency (CNTFRQ)
if (rtsc_frequency <= WallClock::NS_RATIO || rtsc_frequency <= emulated_cpu_frequency ||
rtsc_frequency <= emulated_clock_frequency) {
return std::make_unique<StandardWallClock>(emulated_cpu_frequency,
emulated_clock_frequency);
} else {
@ -85,8 +89,8 @@ std::unique_ptr<WallClock> CreateBestMatchingClock(u32 emulated_cpu_frequency,
#else
std::unique_ptr<WallClock> CreateBestMatchingClock(u32 emulated_cpu_frequency,
u32 emulated_clock_frequency) {
std::unique_ptr<WallClock> CreateBestMatchingClock(u64 emulated_cpu_frequency,
u64 emulated_clock_frequency) {
return std::make_unique<StandardWallClock>(emulated_cpu_frequency, emulated_clock_frequency);
}

8
src/common/wall_clock.h
View file

@ -13,6 +13,10 @@ namespace Common {
class WallClock {
public:
static constexpr u64 NS_RATIO = 1'000'000'000;
static constexpr u64 US_RATIO = 1'000'000;
static constexpr u64 MS_RATIO = 1'000;
virtual ~WallClock() = default;
/// Returns current wall time in nanoseconds
@ -49,7 +53,7 @@ private:
bool is_native;
};
[[nodiscard]] std::unique_ptr<WallClock> CreateBestMatchingClock(u32 emulated_cpu_frequency,
u32 emulated_clock_frequency);
[[nodiscard]] std::unique_ptr<WallClock> CreateBestMatchingClock(u64 emulated_cpu_frequency,
u64 emulated_clock_frequency);
} // namespace Common

6
src/common/x64/native_clock.cpp
View file

@ -47,9 +47,9 @@ NativeClock::NativeClock(u64 emulated_cpu_frequency_, u64 emulated_clock_frequen
_mm_mfence();
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);
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);
}