// Copyright 2020 The Chromium Authors. All rights reserved. // Use of this source code is governed by a BSD-style license that can be // found in the LICENSE file. // This program measures the time taken to decode the given JSON files (the // command line arguments). It is for manual benchmarking. // // Usage: // $ ninja -C out/foobar json_perftest_decodebench // $ out/foobar/json_perftest_decodebench -a -n=10 the/path/to/your/*.json // // The -n=10 switch controls the number of iterations. It defaults to 1. // // The -a switch means to print 1 non-comment line per input file (the average // iteration time). Without this switch (the default), it prints n non-comment // lines per input file (individual iteration times). For a single input file, // building and running this program before and after a particular commit can // work well with the 'ministat' tool: https://github.com/thorduri/ministat #include #include #include #include "base/command_line.h" #include "base/files/file_util.h" #include "base/json/json_reader.h" #include "base/logging.h" #include "base/time/time.h" int main(int argc, char* argv[]) { if (!base::ThreadTicks::IsSupported()) { std::cout << "# base::ThreadTicks is not supported\n"; return EXIT_FAILURE; } base::ThreadTicks::WaitUntilInitialized(); base::CommandLine::Init(argc, argv); base::CommandLine* command_line = base::CommandLine::ForCurrentProcess(); bool average = command_line->HasSwitch("a"); int iterations = 1; std::string iterations_str = command_line->GetSwitchValueASCII("n"); if (!iterations_str.empty()) { iterations = atoi(iterations_str.c_str()); if (iterations < 1) { std::cout << "# invalid -n command line switch\n"; return EXIT_FAILURE; } } if (average) { std::cout << "# Microseconds (μs), n=" << iterations << ", averaged" << std::endl; } else { std::cout << "# Microseconds (μs), n=" << iterations << std::endl; } for (const auto& filename : command_line->GetArgs()) { std::string src; if (!base::ReadFileToString(base::FilePath(filename), &src)) { std::cout << "# could not read " << filename << std::endl; return EXIT_FAILURE; } int64_t total_time = 0; std::string error_message; for (int i = 0; i < iterations; ++i) { auto start = base::ThreadTicks::Now(); auto v = base::JSONReader::ReadAndReturnValueWithError(src); auto end = base::ThreadTicks::Now(); int64_t iteration_time = (end - start).InMicroseconds(); total_time += iteration_time; if (i == 0) { if (average) { error_message = !v.has_value() ? std::move(v.error().message) : std::string(); } else { std::cout << "# " << filename; if (!v.has_value() && !v.error().message.empty()) { std::cout << ": " << v.error().message; } std::cout << std::endl; } } if (!average) { std::cout << iteration_time << std::endl; } } if (average) { int64_t average_time = total_time / iterations; std::cout << std::setw(12) << average_time << "\t# " << filename; if (!error_message.empty()) { std::cout << ": " << error_message; } std::cout << std::endl; } } return EXIT_SUCCESS; }