io_measure

io_measure.cpp

#include <string>
#include <iostream>
#include <chrono>


void synced(const std::string& s, unsigned int n = 0) {
	std::cout.sync_with_stdio(true);
	while (n--) std::cout << s << std::endl;
}


void unsynced(const std::string& s, unsigned int n = 0) {
	std::string tmp = s + "\n";
	std::cout.sync_with_stdio(false);
	while (n--) std::cout << tmp;
}


int main(int argc, char *argv[]) {
	std::string s = "Quite long test string to test the difference in synced and unsynced output stream performance";
	unsigned int n = 1000000;

	if (argc>=2) {
		n = std::strtoul(argv[1], NULL, 10);
	}
	
	auto s1 = std::chrono::high_resolution_clock::now();
	synced(s, n);
	auto e1 = std::chrono::high_resolution_clock::now();
	
	auto s2 = std::chrono::high_resolution_clock::now();
	unsynced(s, n);
	auto e2 = std::chrono::high_resolution_clock::now();

	std::chrono::duration<double> el1 = e1 - s1;
	std::chrono::duration<double> el2 = e2 - s2;

	std::cout << "synced: " << 
		std::chrono::duration_cast<std::chrono::milliseconds>(el1).count()
		<< std::endl;

	std::cout << "unsynced: " << 
		std::chrono::duration_cast<std::chrono::milliseconds>(el2).count()
		<< std::endl;


	return 0;
}