forked from catchorg/Catch2
-
Notifications
You must be signed in to change notification settings - Fork 0
/
catch_estimate_clock.hpp
122 lines (108 loc) · 5.38 KB
/
catch_estimate_clock.hpp
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
// Copyright Catch2 Authors
// Distributed under the Boost Software License, Version 1.0.
// (See accompanying file LICENSE_1_0.txt or copy at
// https://www.boost.org/LICENSE_1_0.txt)
// SPDX-License-Identifier: BSL-1.0
// Adapted from donated nonius code.
#ifndef CATCH_ESTIMATE_CLOCK_HPP_INCLUDED
#define CATCH_ESTIMATE_CLOCK_HPP_INCLUDED
#include <catch2/benchmark/catch_clock.hpp>
#include <catch2/benchmark/catch_environment.hpp>
#include <catch2/benchmark/detail/catch_stats.hpp>
#include <catch2/benchmark/detail/catch_measure.hpp>
#include <catch2/benchmark/detail/catch_run_for_at_least.hpp>
#include <catch2/benchmark/catch_clock.hpp>
#include <catch2/internal/catch_compiler_capabilities.hpp>
#include <catch2/internal/catch_unique_ptr.hpp>
#include <algorithm>
#include <iterator>
#include <vector>
#include <cmath>
namespace Catch {
namespace Benchmark {
namespace Detail {
template <typename Clock>
std::vector<double> resolution(int k) {
std::vector<TimePoint<Clock>> times;
times.reserve(static_cast<size_t>(k + 1));
std::generate_n(std::back_inserter(times), k + 1, now<Clock>{});
std::vector<double> deltas;
deltas.reserve(static_cast<size_t>(k));
std::transform(std::next(times.begin()), times.end(), times.begin(),
std::back_inserter(deltas),
[](TimePoint<Clock> a, TimePoint<Clock> b) { return static_cast<double>((a - b).count()); });
return deltas;
}
const auto warmup_iterations = 10000;
const auto warmup_time = std::chrono::milliseconds(100);
const auto minimum_ticks = 1000;
const auto warmup_seed = 10000;
const auto clock_resolution_estimation_time = std::chrono::milliseconds(500);
const auto clock_cost_estimation_time_limit = std::chrono::seconds(1);
const auto clock_cost_estimation_tick_limit = 100000;
const auto clock_cost_estimation_time = std::chrono::milliseconds(10);
const auto clock_cost_estimation_iterations = 10000;
template <typename Clock>
int warmup() {
return run_for_at_least<Clock>(std::chrono::duration_cast<ClockDuration<Clock>>(warmup_time), warmup_seed, &resolution<Clock>)
.iterations;
}
template <typename Clock>
EnvironmentEstimate<FloatDuration<Clock>> estimate_clock_resolution(int iterations) {
auto r = run_for_at_least<Clock>(std::chrono::duration_cast<ClockDuration<Clock>>(clock_resolution_estimation_time), iterations, &resolution<Clock>)
.result;
return {
FloatDuration<Clock>(mean(r.begin(), r.end())),
classify_outliers(r.begin(), r.end()),
};
}
template <typename Clock>
EnvironmentEstimate<FloatDuration<Clock>> estimate_clock_cost(FloatDuration<Clock> resolution) {
auto time_limit = (std::min)(
resolution * clock_cost_estimation_tick_limit,
FloatDuration<Clock>(clock_cost_estimation_time_limit));
auto time_clock = [](int k) {
return Detail::measure<Clock>([k] {
for (int i = 0; i < k; ++i) {
volatile auto ignored = Clock::now();
(void)ignored;
}
}).elapsed;
};
time_clock(1);
int iters = clock_cost_estimation_iterations;
auto&& r = run_for_at_least<Clock>(std::chrono::duration_cast<ClockDuration<Clock>>(clock_cost_estimation_time), iters, time_clock);
std::vector<double> times;
int nsamples = static_cast<int>(std::ceil(time_limit / r.elapsed));
times.reserve(static_cast<size_t>(nsamples));
std::generate_n(std::back_inserter(times), nsamples, [time_clock, &r] {
return static_cast<double>((time_clock(r.iterations) / r.iterations).count());
});
return {
FloatDuration<Clock>(mean(times.begin(), times.end())),
classify_outliers(times.begin(), times.end()),
};
}
template <typename Clock>
Environment<FloatDuration<Clock>> measure_environment() {
#if defined(CATCH_COMPILER_CLANG)
# pragma clang diagnostic push
# pragma clang diagnostic ignored "-Wexit-time-destructors"
#endif
static Catch::Detail::unique_ptr<Environment<FloatDuration<Clock>>> env;
#if defined(CATCH_COMPILER_CLANG)
# pragma clang diagnostic pop
#endif
if (env) {
return *env;
}
auto iters = Detail::warmup<Clock>();
auto resolution = Detail::estimate_clock_resolution<Clock>(iters);
auto cost = Detail::estimate_clock_cost<Clock>(resolution.mean);
env = Catch::Detail::make_unique<Environment<FloatDuration<Clock>>>( Environment<FloatDuration<Clock>>{resolution, cost} );
return *env;
}
} // namespace Detail
} // namespace Benchmark
} // namespace Catch
#endif // CATCH_ESTIMATE_CLOCK_HPP_INCLUDED