Shared Memory Computing
Understanding Basics of Shared Memory Computing with OpenMP
Processes
- Independent execution units with separate memory spaces
- Each process has its own resources and address space
- Higher overhead for creation and context switching
- Better isolation, security, and stability
#include <iostream>
#include <thread>
#include <unistd.h>
// Process example
int main() {
pid_t pid = fork();
if (pid == 0) {
// Child process
std::cout << "Child process with PID: " << getpid() << std::endl;
} else {
// Parent process
std::cout << "Parent process with PID: " << getpid() << std::endl;
}
return 0;
}Threads
- Lightweight execution units within a single process
- Share memory space, resources, and state
- Lower overhead for creation and context switching
- Efficient communication, but requires synchronization for safe shared access
#include <iostream>
#include <thread>
void threadFunction(int id) {
std::cout << "Thread " << id << " running" << std::endl;
}
int main() {
std::thread t1(threadFunction, 1);
std::thread t2(threadFunction, 2);
t1.join();
t2.join();
return 0;
}Note: This example does not include synchronization. Without synchronization, threads may interleave outputs.