1 // Copyright 2017 The Abseil Authors.
2 //
3 // Licensed under the Apache License, Version 2.0 (the "License");
4 // you may not use this file except in compliance with the License.
5 // You may obtain a copy of the License at
6 //
7 // https://www.apache.org/licenses/LICENSE-2.0
8 //
9 // Unless required by applicable law or agreed to in writing, software
10 // distributed under the License is distributed on an "AS IS" BASIS,
11 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12 // See the License for the specific language governing permissions and
13 // limitations under the License.
14 //
15 #include "absl/random/internal/randen.h"
16
17 #include <cstdint>
18 #include <cstdio>
19 #include <cstring>
20
21 #include "absl/base/internal/raw_logging.h"
22 #include "absl/random/internal/nanobenchmark.h"
23 #include "absl/random/internal/platform.h"
24 #include "absl/random/internal/randen_engine.h"
25 #include "absl/random/internal/randen_hwaes.h"
26 #include "absl/random/internal/randen_slow.h"
27 #include "absl/strings/numbers.h"
28
29 namespace {
30
31 using absl::random_internal::Randen;
32 using absl::random_internal::RandenHwAes;
33 using absl::random_internal::RandenSlow;
34
35 using absl::random_internal_nanobenchmark::FuncInput;
36 using absl::random_internal_nanobenchmark::FuncOutput;
37 using absl::random_internal_nanobenchmark::InvariantTicksPerSecond;
38 using absl::random_internal_nanobenchmark::MeasureClosure;
39 using absl::random_internal_nanobenchmark::Params;
40 using absl::random_internal_nanobenchmark::PinThreadToCPU;
41 using absl::random_internal_nanobenchmark::Result;
42
43 // Local state parameters.
44 static constexpr size_t kStateSizeT = Randen::kStateBytes / sizeof(uint64_t);
45 static constexpr size_t kSeedSizeT = Randen::kSeedBytes / sizeof(uint32_t);
46
47 // Randen implementation benchmarks.
48 template <typename T>
49 struct AbsorbFn : public T {
50 // These are both cast to uint128* in the RandenHwAes implementation, so
51 // ensure they are 16 byte aligned.
52 alignas(16) mutable uint64_t state[kStateSizeT] = {};
53 alignas(16) mutable uint32_t seed[kSeedSizeT] = {};
54
bytes__anon8b705eec0111::AbsorbFn55 static constexpr size_t bytes() { return sizeof(seed); }
56
operator ()__anon8b705eec0111::AbsorbFn57 FuncOutput operator()(const FuncInput num_iters) const {
58 for (size_t i = 0; i < num_iters; ++i) {
59 this->Absorb(seed, state);
60 }
61 return state[0];
62 }
63 };
64
65 template <typename T>
66 struct GenerateFn : public T {
67 mutable uint64_t state[kStateSizeT];
GenerateFn__anon8b705eec0111::GenerateFn68 GenerateFn() { std::memset(state, 0, sizeof(state)); }
69
bytes__anon8b705eec0111::GenerateFn70 static constexpr size_t bytes() { return sizeof(state); }
71
operator ()__anon8b705eec0111::GenerateFn72 FuncOutput operator()(const FuncInput num_iters) const {
73 const auto* keys = this->GetKeys();
74 for (size_t i = 0; i < num_iters; ++i) {
75 this->Generate(keys, state);
76 }
77 return state[0];
78 }
79 };
80
81 template <typename UInt>
82 struct Engine {
83 mutable absl::random_internal::randen_engine<UInt> rng;
84
bytes__anon8b705eec0111::Engine85 static constexpr size_t bytes() { return sizeof(UInt); }
86
operator ()__anon8b705eec0111::Engine87 FuncOutput operator()(const FuncInput num_iters) const {
88 for (size_t i = 0; i < num_iters - 1; ++i) {
89 rng();
90 }
91 return rng();
92 }
93 };
94
95 template <size_t N>
Print(const char * name,const size_t n,const Result (& results)[N],const size_t bytes)96 void Print(const char* name, const size_t n, const Result (&results)[N],
97 const size_t bytes) {
98 if (n == 0) {
99 ABSL_RAW_LOG(
100 WARNING,
101 "WARNING: Measurement failed, should not happen when using "
102 "PinThreadToCPU unless the region to measure takes > 1 second.\n");
103 return;
104 }
105
106 static const double ns_per_tick = 1e9 / InvariantTicksPerSecond();
107 static constexpr const double kNsPerS = 1e9; // ns/s
108 static constexpr const double kMBPerByte = 1.0 / 1048576.0; // Mb / b
109 static auto header = [] {
110 return printf("%20s %8s: %12s ticks; %9s (%9s) %8s\n", "Name", "Count",
111 "Total", "Variance", "Time", "bytes/s");
112 }();
113 (void)header;
114
115 for (size_t i = 0; i < n; ++i) {
116 const double ticks_per_call = results[i].ticks / results[i].input;
117 const double ns_per_call = ns_per_tick * ticks_per_call;
118 const double bytes_per_ns = bytes / ns_per_call;
119 const double mb_per_s = bytes_per_ns * kNsPerS * kMBPerByte;
120 // Output
121 printf("%20s %8zu: %12.2f ticks; MAD=%4.2f%% (%6.1f ns) %8.1f Mb/s\n",
122 name, results[i].input, results[i].ticks,
123 results[i].variability * 100.0, ns_per_call, mb_per_s);
124 }
125 }
126
127 // Fails here
128 template <typename Op, size_t N>
Measure(const char * name,const FuncInput (& inputs)[N])129 void Measure(const char* name, const FuncInput (&inputs)[N]) {
130 Op op;
131
132 Result results[N];
133 Params params;
134 params.verbose = false;
135 params.max_evals = 6; // avoid test timeout
136 const size_t num_results = MeasureClosure(op, inputs, N, results, params);
137 Print(name, num_results, results, op.bytes());
138 }
139
140 // unpredictable == 1 but the compiler does not know that.
RunAll(const int argc,char * argv[])141 void RunAll(const int argc, char* argv[]) {
142 if (argc == 2) {
143 int cpu = -1;
144 if (!absl::SimpleAtoi(argv[1], &cpu)) {
145 ABSL_RAW_LOG(FATAL, "The optional argument must be a CPU number >= 0.\n");
146 }
147 PinThreadToCPU(cpu);
148 }
149
150 // The compiler cannot reduce this to a constant.
151 const FuncInput unpredictable = (argc != 999);
152 static const FuncInput inputs[] = {unpredictable * 100, unpredictable * 1000};
153
154 #if !defined(ABSL_INTERNAL_DISABLE_AES) && ABSL_HAVE_ACCELERATED_AES
155 Measure<AbsorbFn<RandenHwAes>>("Absorb (HwAes)", inputs);
156 #endif
157 Measure<AbsorbFn<RandenSlow>>("Absorb (Slow)", inputs);
158
159 #if !defined(ABSL_INTERNAL_DISABLE_AES) && ABSL_HAVE_ACCELERATED_AES
160 Measure<GenerateFn<RandenHwAes>>("Generate (HwAes)", inputs);
161 #endif
162 Measure<GenerateFn<RandenSlow>>("Generate (Slow)", inputs);
163
164 // Measure the production engine.
165 static const FuncInput inputs1[] = {unpredictable * 1000,
166 unpredictable * 10000};
167 Measure<Engine<uint64_t>>("randen_engine<uint64_t>", inputs1);
168 Measure<Engine<uint32_t>>("randen_engine<uint32_t>", inputs1);
169 }
170
171 } // namespace
172
main(int argc,char * argv[])173 int main(int argc, char* argv[]) {
174 RunAll(argc, argv);
175 return 0;
176 }
177