sampling vs instrumentation

sleepy_fib.cpp

#include <chrono>
#include <random>
#include <iostream>
#include <thread>

int fib(int x) {
	if (x == 0)
		return 0;
	if (x == 1)
		return 1;
	return fib(x - 1) + fib(x - 2);
}

__declspec(noinline) void sleep(std::chrono::duration<double, std::milli> time) {
	std::cout << "sleep(" << time.count() << ")\n";
	std::this_thread::sleep_for(time);
}

int main()  {
	std::mt19937 rng;
	std::uniform_int_distribution<int> dis(28, 32);
	for (int i = 0; i < 1000; ++i) {
		auto start = std::chrono::high_resolution_clock::now();
		auto r = dis(rng);
		auto f = fib(r);
		std::cout << "fib(" << r << ") = " << f << "\n";
		auto end = std::chrono::high_resolution_clock::now();
		std::chrono::duration<double, std::milli> delta = end - start;
		sleep(delta);
	}
}