1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
|
// Copyright 2020 yuzu Emulator Project
// Licensed under GPLv2 or any later version
// Refer to the license.txt file included.
#include <array>
#include <chrono>
#include <thread>
#include "common/atomic_ops.h"
#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.
FencedRDTSC();
std::this_thread::sleep_for(std::chrono::milliseconds{1});
FencedRDTSC();
// Get the current time.
const auto start_time = std::chrono::steady_clock::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();
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;
}
namespace X64 {
NativeClock::NativeClock(u64 emulated_cpu_frequency_, u64 emulated_clock_frequency_,
u64 rtsc_frequency_)
: WallClock(emulated_cpu_frequency_, emulated_clock_frequency_, true), rtsc_frequency{
rtsc_frequency_} {
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);
}
u64 NativeClock::GetRTSC() {
TimePoint new_time_point{};
TimePoint current_time_point{};
current_time_point.pack = Common::AtomicLoad128(time_point.pack.data());
do {
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
? current_measure
: 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));
/// The clock cannot be more precise than the guest timer, remove the lower bits
return new_time_point.inner.accumulated_ticks & inaccuracy_mask;
}
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 {
new_time_point.pack = current_time_point.pack;
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));
}
}
std::chrono::nanoseconds NativeClock::GetTimeNS() {
const u64 rtsc_value = GetRTSC();
return std::chrono::nanoseconds{MultiplyHigh(rtsc_value, ns_rtsc_factor)};
}
std::chrono::microseconds NativeClock::GetTimeUS() {
const u64 rtsc_value = GetRTSC();
return std::chrono::microseconds{MultiplyHigh(rtsc_value, us_rtsc_factor)};
}
std::chrono::milliseconds NativeClock::GetTimeMS() {
const u64 rtsc_value = GetRTSC();
return std::chrono::milliseconds{MultiplyHigh(rtsc_value, ms_rtsc_factor)};
}
u64 NativeClock::GetClockCycles() {
const u64 rtsc_value = GetRTSC();
return MultiplyHigh(rtsc_value, clock_rtsc_factor);
}
u64 NativeClock::GetCPUCycles() {
const u64 rtsc_value = GetRTSC();
return MultiplyHigh(rtsc_value, cpu_rtsc_factor);
}
} // namespace X64
} // namespace Common
|
