Work False Sharing

Work.h

// ConsoleApplication1.cpp : Defines the entry point for the console application.
//
// 
//  Protheus
//
//  Created by Joshua Waring on 4/06/2015. 
//

#include <iostream>
#include <thread> 

//#define FALSE_SHARING

#ifdef FALSE_SHARING

void worker(volatile unsigned long long* work_done, int thread_id, volatile bool* working, volatile bool* start) {
	while (!start);
	while (working)
		work_done[thread_id]++;
}

const int THREAD_COUNT = 4;

int main() {
	volatile bool working = true;
	volatile bool start = false;
	volatile unsigned long long work_done[THREAD_COUNT];
	memset((void*)work_done, 0, sizeof(unsigned long long) * THREAD_COUNT);
	for (int x = 0; x < THREAD_COUNT; x++)
		std::thread(&worker, work_done, x, &working, &start).detach();

	start = true;
	std::this_thread::sleep_for(std::chrono::seconds(5));

	// We check while the threads working, to fit in with
	// the use case
	for (int x = 0; x < THREAD_COUNT; x++)
		std::cout << work_done[x] << std::endl;
	working = false;
	return 0;
}

#else

int worker(volatile unsigned long long** work_done, volatile bool* working, volatile bool* start) {
	volatile unsigned long long value = 0;
	*work_done = &value;
	while (!start);
	while (working)
		value++;
	return value;
}

const int THREAD_COUNT = 4;

int main() {
	volatile bool working = true;
	volatile bool start = false;
	volatile unsigned long long* work_done[THREAD_COUNT];
	memset(work_done, 0, sizeof(unsigned long long) * THREAD_COUNT);
	for (int x = 0; x < THREAD_COUNT; x++)
		std::thread(&worker, &work_done[x], &working, &start).detach();

	start = true;
	std::this_thread::sleep_for(std::chrono::seconds(5));

	// We check while the threads working, to fit in with
	// the use case
	for (int x = 0; x < THREAD_COUNT; x++)
		std::cout << *work_done[x] << std::endl;
	working = false;
	return 0;
}
#endif