1// Copyright 2015 Google Inc. All rights reserved.
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// http://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 "benchmark_runner.h"
16#include "benchmark/benchmark.h"
17#include "benchmark_api_internal.h"
18#include "internal_macros.h"
19
20#ifndef BENCHMARK_OS_WINDOWS
21#ifndef BENCHMARK_OS_FUCHSIA
22#include <sys/resource.h>
23#endif
24#include <sys/time.h>
25#include <unistd.h>
26#endif
27
28#include <algorithm>
29#include <atomic>
30#include <condition_variable>
31#include <cstdio>
32#include <cstdlib>
33#include <fstream>
34#include <iostream>
35#include <memory>
36#include <string>
37#include <thread>
38#include <utility>
39
40#include "check.h"
41#include "colorprint.h"
42#include "commandlineflags.h"
43#include "complexity.h"
44#include "counter.h"
45#include "internal_macros.h"
46#include "log.h"
47#include "mutex.h"
48#include "re.h"
49#include "statistics.h"
50#include "string_util.h"
51#include "thread_manager.h"
52#include "thread_timer.h"
53
54namespace benchmark {
55
56namespace internal {
57
58MemoryManager* memory_manager = nullptr;
59
60namespace {
61
62static constexpr IterationCount kMaxIterations = 1000000000;
63
64BenchmarkReporter::Run CreateRunReport(
65 const benchmark::internal::BenchmarkInstance& b,
66 const internal::ThreadManager::Result& results,
67 IterationCount memory_iterations,
68 const MemoryManager::Result& memory_result, double seconds,
69 int64_t repetition_index) {
70 // Create report about this benchmark run.
71 BenchmarkReporter::Run report;
72
73 report.run_name = b.name;
74 report.error_occurred = results.has_error_;
75 report.error_message = results.error_message_;
76 report.report_label = results.report_label_;
77 // This is the total iterations across all threads.
78 report.iterations = results.iterations;
79 report.time_unit = b.time_unit;
80 report.threads = b.threads;
81 report.repetition_index = repetition_index;
82 report.repetitions = b.repetitions;
83
84 if (!report.error_occurred) {
85 if (b.use_manual_time) {
86 report.real_accumulated_time = results.manual_time_used;
87 } else {
88 report.real_accumulated_time = results.real_time_used;
89 }
90 report.cpu_accumulated_time = results.cpu_time_used;
91 report.complexity_n = results.complexity_n;
92 report.complexity = b.complexity;
93 report.complexity_lambda = b.complexity_lambda;
94 report.statistics = b.statistics;
95 report.counters = results.counters;
96
97 if (memory_iterations > 0) {
98 report.has_memory_result = true;
99 report.allocs_per_iter =
100 memory_iterations ? static_cast<double>(memory_result.num_allocs) /
101 memory_iterations
102 : 0;
103 report.max_bytes_used = memory_result.max_bytes_used;
104 }
105
106 internal::Finish(&report.counters, results.iterations, seconds, b.threads);
107 }
108 return report;
109}
110
111// Execute one thread of benchmark b for the specified number of iterations.
112// Adds the stats collected for the thread into *total.
113void RunInThread(const BenchmarkInstance* b, IterationCount iters,
114 int thread_id, ThreadManager* manager) {
115 internal::ThreadTimer timer(
116 b->measure_process_cpu_time
117 ? internal::ThreadTimer::CreateProcessCpuTime()
118 : internal::ThreadTimer::Create());
119 State st = b->Run(iters, thread_id, &timer, manager);
120 CHECK(st.iterations() >= st.max_iterations)
121 << "Benchmark returned before State::KeepRunning() returned false!";
122 {
123 MutexLock l(manager->GetBenchmarkMutex());
124 internal::ThreadManager::Result& results = manager->results;
125 results.iterations += st.iterations();
126 results.cpu_time_used += timer.cpu_time_used();
127 results.real_time_used += timer.real_time_used();
128 results.manual_time_used += timer.manual_time_used();
129 results.complexity_n += st.complexity_length_n();
130 internal::Increment(&results.counters, st.counters);
131 }
132 manager->NotifyThreadComplete();
133}
134
135class BenchmarkRunner {
136 public:
137 BenchmarkRunner(const benchmark::internal::BenchmarkInstance& b_,
138 std::vector<BenchmarkReporter::Run>* complexity_reports_)
139 : b(b_),
140 complexity_reports(*complexity_reports_),
141 min_time(!IsZero(b.min_time) ? b.min_time : FLAGS_benchmark_min_time),
142 repeats(b.repetitions != 0 ? b.repetitions
143 : FLAGS_benchmark_repetitions),
144 has_explicit_iteration_count(b.iterations != 0),
145 pool(b.threads - 1),
146 iters(has_explicit_iteration_count ? b.iterations : 1) {
147 run_results.display_report_aggregates_only =
148 (FLAGS_benchmark_report_aggregates_only ||
149 FLAGS_benchmark_display_aggregates_only);
150 run_results.file_report_aggregates_only =
151 FLAGS_benchmark_report_aggregates_only;
152 if (b.aggregation_report_mode != internal::ARM_Unspecified) {
153 run_results.display_report_aggregates_only =
154 (b.aggregation_report_mode &
155 internal::ARM_DisplayReportAggregatesOnly);
156 run_results.file_report_aggregates_only =
157 (b.aggregation_report_mode & internal::ARM_FileReportAggregatesOnly);
158 }
159
160 for (int repetition_num = 0; repetition_num < repeats; repetition_num++) {
161 DoOneRepetition(repetition_num);
162 }
163
164 // Calculate additional statistics
165 run_results.aggregates_only = ComputeStats(run_results.non_aggregates);
166
167 // Maybe calculate complexity report
168 if ((b.complexity != oNone) && b.last_benchmark_instance) {
169 auto additional_run_stats = ComputeBigO(complexity_reports);
170 run_results.aggregates_only.insert(run_results.aggregates_only.end(),
171 additional_run_stats.begin(),
172 additional_run_stats.end());
173 complexity_reports.clear();
174 }
175 }
176
177 RunResults&& get_results() { return std::move(run_results); }
178
179 private:
180 RunResults run_results;
181
182 const benchmark::internal::BenchmarkInstance& b;
183 std::vector<BenchmarkReporter::Run>& complexity_reports;
184
185 const double min_time;
186 const int repeats;
187 const bool has_explicit_iteration_count;
188
189 std::vector<std::thread> pool;
190
191 IterationCount iters; // preserved between repetitions!
192 // So only the first repetition has to find/calculate it,
193 // the other repetitions will just use that precomputed iteration count.
194
195 struct IterationResults {
196 internal::ThreadManager::Result results;
197 IterationCount iters;
198 double seconds;
199 };
200 IterationResults DoNIterations() {
201 VLOG(2) << "Running " << b.name.str() << " for " << iters << "\n";
202
203 std::unique_ptr<internal::ThreadManager> manager;
204 manager.reset(new internal::ThreadManager(b.threads));
205
206 // Run all but one thread in separate threads
207 for (std::size_t ti = 0; ti < pool.size(); ++ti) {
208 pool[ti] = std::thread(&RunInThread, &b, iters, static_cast<int>(ti + 1),
209 manager.get());
210 }
211 // And run one thread here directly.
212 // (If we were asked to run just one thread, we don't create new threads.)
213 // Yes, we need to do this here *after* we start the separate threads.
214 RunInThread(&b, iters, 0, manager.get());
215
216 // The main thread has finished. Now let's wait for the other threads.
217 manager->WaitForAllThreads();
218 for (std::thread& thread : pool) thread.join();
219
220 IterationResults i;
221 // Acquire the measurements/counters from the manager, UNDER THE LOCK!
222 {
223 MutexLock l(manager->GetBenchmarkMutex());
224 i.results = manager->results;
225 }
226
227 // And get rid of the manager.
228 manager.reset();
229
230 // Adjust real/manual time stats since they were reported per thread.
231 i.results.real_time_used /= b.threads;
232 i.results.manual_time_used /= b.threads;
233 // If we were measuring whole-process CPU usage, adjust the CPU time too.
234 if (b.measure_process_cpu_time) i.results.cpu_time_used /= b.threads;
235
236 VLOG(2) << "Ran in " << i.results.cpu_time_used << "/"
237 << i.results.real_time_used << "\n";
238
239 // So for how long were we running?
240 i.iters = iters;
241 // Base decisions off of real time if requested by this benchmark.
242 i.seconds = i.results.cpu_time_used;
243 if (b.use_manual_time) {
244 i.seconds = i.results.manual_time_used;
245 } else if (b.use_real_time) {
246 i.seconds = i.results.real_time_used;
247 }
248
249 return i;
250 }
251
252 IterationCount PredictNumItersNeeded(const IterationResults& i) const {
253 // See how much iterations should be increased by.
254 // Note: Avoid division by zero with max(seconds, 1ns).
255 double multiplier = min_time * 1.4 / std::max(i.seconds, 1e-9);
256 // If our last run was at least 10% of FLAGS_benchmark_min_time then we
257 // use the multiplier directly.
258 // Otherwise we use at most 10 times expansion.
259 // NOTE: When the last run was at least 10% of the min time the max
260 // expansion should be 14x.
261 bool is_significant = (i.seconds / min_time) > 0.1;
262 multiplier = is_significant ? multiplier : std::min(10.0, multiplier);
263 if (multiplier <= 1.0) multiplier = 2.0;
264
265 // So what seems to be the sufficiently-large iteration count? Round up.
266 const IterationCount max_next_iters =
267 0.5 + std::max(multiplier * i.iters, i.iters + 1.0);
268 // But we do have *some* sanity limits though..
269 const IterationCount next_iters = std::min(max_next_iters, kMaxIterations);
270
271 VLOG(3) << "Next iters: " << next_iters << ", " << multiplier << "\n";
272 return next_iters; // round up before conversion to integer.
273 }
274
275 bool ShouldReportIterationResults(const IterationResults& i) const {
276 // Determine if this run should be reported;
277 // Either it has run for a sufficient amount of time
278 // or because an error was reported.
279 return i.results.has_error_ ||
280 i.iters >= kMaxIterations || // Too many iterations already.
281 i.seconds >= min_time || // The elapsed time is large enough.
282 // CPU time is specified but the elapsed real time greatly exceeds
283 // the minimum time.
284 // Note that user provided timers are except from this sanity check.
285 ((i.results.real_time_used >= 5 * min_time) && !b.use_manual_time);
286 }
287
288 void DoOneRepetition(int64_t repetition_index) {
289 const bool is_the_first_repetition = repetition_index == 0;
290 IterationResults i;
291
292 // We *may* be gradually increasing the length (iteration count)
293 // of the benchmark until we decide the results are significant.
294 // And once we do, we report those last results and exit.
295 // Please do note that the if there are repetitions, the iteration count
296 // is *only* calculated for the *first* repetition, and other repetitions
297 // simply use that precomputed iteration count.
298 for (;;) {
299 i = DoNIterations();
300
301 // Do we consider the results to be significant?
302 // If we are doing repetitions, and the first repetition was already done,
303 // it has calculated the correct iteration time, so we have run that very
304 // iteration count just now. No need to calculate anything. Just report.
305 // Else, the normal rules apply.
306 const bool results_are_significant = !is_the_first_repetition ||
307 has_explicit_iteration_count ||
308 ShouldReportIterationResults(i);
309
310 if (results_are_significant) break; // Good, let's report them!
311
312 // Nope, bad iteration. Let's re-estimate the hopefully-sufficient
313 // iteration count, and run the benchmark again...
314
315 iters = PredictNumItersNeeded(i);
316 assert(iters > i.iters &&
317 "if we did more iterations than we want to do the next time, "
318 "then we should have accepted the current iteration run.");
319 }
320
321 // Oh, one last thing, we need to also produce the 'memory measurements'..
322 MemoryManager::Result memory_result;
323 IterationCount memory_iterations = 0;
324 if (memory_manager != nullptr) {
325 // Only run a few iterations to reduce the impact of one-time
326 // allocations in benchmarks that are not properly managed.
327 memory_iterations = std::min<IterationCount>(16, iters);
328 memory_manager->Start();
329 std::unique_ptr<internal::ThreadManager> manager;
330 manager.reset(new internal::ThreadManager(1));
331 RunInThread(&b, memory_iterations, 0, manager.get());
332 manager->WaitForAllThreads();
333 manager.reset();
334
335 memory_manager->Stop(&memory_result);
336 }
337
338 // Ok, now actualy report.
339 BenchmarkReporter::Run report =
340 CreateRunReport(b, i.results, memory_iterations, memory_result,
341 i.seconds, repetition_index);
342
343 if (!report.error_occurred && b.complexity != oNone)
344 complexity_reports.push_back(report);
345
346 run_results.non_aggregates.push_back(report);
347 }
348};
349
350} // end namespace
351
352RunResults RunBenchmark(
353 const benchmark::internal::BenchmarkInstance& b,
354 std::vector<BenchmarkReporter::Run>* complexity_reports) {
355 internal::BenchmarkRunner r(b, complexity_reports);
356 return r.get_results();
357}
358
359} // end namespace internal
360
361} // end namespace benchmark
362