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/reporter.h"
16
17#include <cstdlib>
18#include <vector>
19
20#include "check.h"
21#include "stat.h"
22
23namespace benchmark {
24
25void BenchmarkReporter::ComputeStats(
26    const std::vector<Run>& reports,
27    Run* mean_data, Run* stddev_data) {
28  CHECK(reports.size() >= 2) << "Cannot compute stats for less than 2 reports";
29  // Accumulators.
30  Stat1_d real_accumulated_time_stat;
31  Stat1_d cpu_accumulated_time_stat;
32  Stat1_d bytes_per_second_stat;
33  Stat1_d items_per_second_stat;
34  // All repetitions should be run with the same number of iterations so we
35  // can take this information from the first benchmark.
36  int64_t const run_iterations = reports.front().iterations;
37
38  // Populate the accumulators.
39  for (Run const& run : reports) {
40    CHECK_EQ(reports[0].benchmark_name, run.benchmark_name);
41    CHECK_EQ(run_iterations, run.iterations);
42    real_accumulated_time_stat +=
43        Stat1_d(run.real_accumulated_time/run.iterations, run.iterations);
44    cpu_accumulated_time_stat +=
45        Stat1_d(run.cpu_accumulated_time/run.iterations, run.iterations);
46    items_per_second_stat += Stat1_d(run.items_per_second, run.iterations);
47    bytes_per_second_stat += Stat1_d(run.bytes_per_second, run.iterations);
48  }
49
50  // Get the data from the accumulator to BenchmarkReporter::Run's.
51  mean_data->benchmark_name = reports[0].benchmark_name + "_mean";
52  mean_data->iterations = run_iterations;
53  mean_data->real_accumulated_time = real_accumulated_time_stat.Mean() *
54                                     run_iterations;
55  mean_data->cpu_accumulated_time = cpu_accumulated_time_stat.Mean() *
56                                    run_iterations;
57  mean_data->bytes_per_second = bytes_per_second_stat.Mean();
58  mean_data->items_per_second = items_per_second_stat.Mean();
59
60  // Only add label to mean/stddev if it is same for all runs
61  mean_data->report_label = reports[0].report_label;
62  for (std::size_t i = 1; i < reports.size(); i++) {
63    if (reports[i].report_label != reports[0].report_label) {
64      mean_data->report_label = "";
65      break;
66    }
67  }
68
69  stddev_data->benchmark_name = reports[0].benchmark_name + "_stddev";
70  stddev_data->report_label = mean_data->report_label;
71  stddev_data->iterations = 0;
72  stddev_data->real_accumulated_time =
73      real_accumulated_time_stat.StdDev();
74  stddev_data->cpu_accumulated_time =
75      cpu_accumulated_time_stat.StdDev();
76  stddev_data->bytes_per_second = bytes_per_second_stat.StdDev();
77  stddev_data->items_per_second = items_per_second_stat.StdDev();
78}
79
80void BenchmarkReporter::Finalize() {
81}
82
83BenchmarkReporter::~BenchmarkReporter() {
84}
85
86} // end namespace benchmark
87