yuzu/src/common/wall_clock.cpp
Morph bb4e676155 wall_clock: Increase precision requirements
We are providing a conversion to nanoseconds in NativeClock, which is more precise than the GPU tick.
2023-07-27 18:40:56 -04:00

76 lines
2.1 KiB
C++

// SPDX-FileCopyrightText: Copyright 2020 yuzu Emulator Project
// SPDX-License-Identifier: GPL-2.0-or-later
#include "common/steady_clock.h"
#include "common/wall_clock.h"
#ifdef ARCHITECTURE_x86_64
#include "common/x64/cpu_detect.h"
#include "common/x64/native_clock.h"
#include "common/x64/rdtsc.h"
#endif
namespace Common {
class StandardWallClock final : public WallClock {
public:
explicit StandardWallClock() : start_time{SteadyClock::Now()} {}
std::chrono::nanoseconds GetTimeNS() const override {
return SteadyClock::Now() - start_time;
}
std::chrono::microseconds GetTimeUS() const override {
return static_cast<std::chrono::microseconds>(GetHostTicksElapsed() / NsToUsRatio::den);
}
std::chrono::milliseconds GetTimeMS() const override {
return static_cast<std::chrono::milliseconds>(GetHostTicksElapsed() / NsToMsRatio::den);
}
u64 GetCNTPCT() const override {
return GetHostTicksElapsed() * NsToCNTPCTRatio::num / NsToCNTPCTRatio::den;
}
u64 GetGPUTick() const override {
return GetHostTicksElapsed() * NsToGPUTickRatio::num / NsToGPUTickRatio::den;
}
u64 GetHostTicksNow() const override {
return static_cast<u64>(SteadyClock::Now().time_since_epoch().count());
}
u64 GetHostTicksElapsed() const override {
return static_cast<u64>(GetTimeNS().count());
}
bool IsNative() const override {
return false;
}
private:
SteadyClock::time_point start_time;
};
std::unique_ptr<WallClock> CreateOptimalClock() {
#ifdef ARCHITECTURE_x86_64
const auto& caps = GetCPUCaps();
if (caps.invariant_tsc && caps.tsc_frequency >= std::nano::den) {
return std::make_unique<X64::NativeClock>(caps.tsc_frequency);
} else {
// Fallback to StandardWallClock if the hardware TSC
// - Is not invariant
// - Is not more precise than 1 GHz (1ns resolution)
return std::make_unique<StandardWallClock>();
}
#else
return std::make_unique<StandardWallClock>();
#endif
}
std::unique_ptr<WallClock> CreateStandardWallClock() {
return std::make_unique<StandardWallClock>();
}
} // namespace Common