simdjson/benchmark/perfdiff.cpp

115 lines
3.8 KiB
C++

#include <cstdio>
#include <iostream>
#include <memory>
#include <stdexcept>
#include <string>
#include <sstream>
#include <array>
#include <algorithm>
#include <vector>
#include <cmath>
#ifdef _WIN32
#define popen _popen
#define pclose _pclose
#endif
int closepipe(FILE *pipe) {
int exit_code = pclose(pipe);
if (exit_code != EXIT_SUCCESS) {
std::cerr << "Error " << exit_code << " running benchmark command!" << std::endl;
exit(EXIT_FAILURE);
};
return exit_code;
}
std::string exec(const char* cmd) {
std::cerr << cmd << std::endl;
std::array<char, 128> buffer;
std::string result;
std::unique_ptr<FILE, decltype(&closepipe)> pipe(popen(cmd, "r"), closepipe);
if (!pipe) {
std::cerr << "popen() failed!" << std::endl;
abort();
}
while (fgets(buffer.data(), int(buffer.size()), pipe.get()) != nullptr) {
result += buffer.data();
}
return result;
}
double readThroughput(std::string parseOutput) {
std::istringstream output(parseOutput);
std::string line;
double result = 0;
int numResults = 0;
while (std::getline(output, line)) {
std::string::size_type pos = 0;
for (int i=0; i<5; i++) {
pos = line.find('\t', pos);
if (pos == std::string::npos) {
std::cerr << "Command printed out a line with less than 5 fields in it:\n" << line << std::endl;
}
pos++;
}
result += std::stod(line.substr(pos));
numResults++;
}
if (numResults == 0) {
std::cerr << "No results returned from benchmark command!" << std::endl;
exit(EXIT_FAILURE);
}
return result / numResults;
}
const double INTERLEAVED_ATTEMPTS = 7;
int main(int argc, const char *argv[]) {
if (argc < 3) {
std::cerr << "Usage: " << argv[0] << " <old parse exe> <new parse exe> [<parse arguments>]" << std::endl;
return 1;
}
std::string newCommand = argv[1];
std::string refCommand = argv[2];
for (int i=3; i<argc; i++) {
newCommand += " ";
newCommand += argv[i];
refCommand += " ";
refCommand += argv[i];
}
std::vector<double> ref;
std::vector<double> newcode;
for (int attempt=0; attempt < INTERLEAVED_ATTEMPTS; attempt++) {
std::cout << "Attempt #" << (attempt+1) << " of " << INTERLEAVED_ATTEMPTS << std::endl;
// Read new throughput
double newThroughput = readThroughput(exec(newCommand.c_str()));
std::cout << "New throughput: " << newThroughput << std::endl;
newcode.push_back(newThroughput);
// Read reference throughput
double referenceThroughput = readThroughput(exec(refCommand.c_str()));
std::cout << "Ref throughput: " << referenceThroughput << std::endl;
ref.push_back(referenceThroughput);
}
// we check if the maximum of newcode is lower than minimum of ref, if so we have a problem so fail!
double worseref = *std::min_element(ref.begin(), ref.end());
double bestnewcode = *std::max_element(newcode.begin(), newcode.end());
double bestref = *std::max_element(ref.begin(), ref.end());
double worsenewcode = *std::min_element(newcode.begin(), newcode.end());
std::cout << "The new code has a throughput in " << worsenewcode << " -- " << bestnewcode << std::endl;
std::cout << "The reference code has a throughput in " << worseref << " -- " << bestref << std::endl;
if(bestnewcode < worseref) {
std::cerr << "You probably have a performance degradation." << std::endl;
return EXIT_FAILURE;
}
if(bestnewcode < worseref) {
std::cout << "You probably have a performance gain." << std::endl;
return EXIT_SUCCESS;
}
std::cout << "There is no obvious performance difference. A manual check might be needed." << std::endl;
return EXIT_SUCCESS;
}