94 lines
2.2 KiB
C++
94 lines
2.2 KiB
C++
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#include <chrono>
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#include <cmath>
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#include <iomanip>
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#include <iostream>
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#include <glog/logging.h>
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#include <glog/raw_logging.h>
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const size_t kNumIterations = 50 * 1000;
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const size_t kNumRuns = 10;
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const double kPi = 3.1415926535897932384626433;
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static long long now_ns()
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{
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using namespace std::chrono;
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return duration_cast<nanoseconds>(high_resolution_clock::now().time_since_epoch()).count();
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}
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template<typename Function>
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double time_sec(const Function& function)
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{
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auto start_ns = now_ns();
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function();
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return (now_ns() - start_ns) * 1e-9;
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}
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template<typename Function>
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void bench(const std::string& name, const Function& function)
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{
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function(); // Warm-up
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printf("%-30s ", name.c_str());
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fflush(stdout);
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std::vector<double> times;
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double sum = 0;
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for (size_t i = 0; i < kNumRuns; ++i)
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{
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times.push_back(time_sec(function) / kNumIterations);
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sum += times.back();
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}
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double mean = sum / kNumRuns;
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double std_dev_sum = 0;
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for (double time : times) {
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std_dev_sum += (time - mean) * (time - mean);
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}
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double variance = std::sqrt(std_dev_sum / kNumRuns);
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printf("%6.3f +- %.3f us per call\n", mean * 1e6, variance * 1e6);
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fflush(stdout);
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}
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// ----------------------------------------------------------------------------
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void stream_strings()
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{
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for (size_t i = 0; i < kNumIterations; ++i) {
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LOG(WARNING) << "Some long, complex message.";
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}
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google::FlushLogFiles(google::GLOG_INFO);
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}
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void stream_float()
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{
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for (size_t i = 0; i < kNumIterations; ++i) {
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LOG(WARNING) << std::setfill('0') << std::setw(6) << std::setprecision(3) << kPi;
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}
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google::FlushLogFiles(google::GLOG_INFO);
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}
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void raw_string_float()
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{
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for (size_t i = 0; i < kNumIterations; ++i) {
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RAW_LOG(WARNING, "Some long, complex message.");
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}
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google::FlushLogFiles(google::GLOG_INFO);
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}
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int main(int argc, char* argv[])
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{
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FLAGS_alsologtostderr = true;
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google::ParseCommandLineFlags(&argc, &argv, true);
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google::InitGoogleLogging(argv[0]);
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bench("LOG(WARNING) << string (buffered):", stream_strings);
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bench("LOG(WARNING) << float (buffered):", stream_float);
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FLAGS_logbufsecs = 0; // Flush all output in realtime
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bench("LOG(WARNING) << string (unbuffered):", stream_strings);
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bench("LOG(WARNING) << float (unbuffered):", stream_float);
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}
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