Question

I’m writing a program with a consumer thread and a producer thread, now it seems queue synchronization is a big overhead in the program, and I looked for some lock free queue implementations, but only found Lamport’s version and an improved version on PPoPP ’08:

enqueue_nonblock(data) {
    if (NULL != buffer[head]) {
        return EWOULDBLOCK;
    }
    buffer[head] = data;
    head = NEXT(head);
    return 0;
}

dequeue_nonblock(data) {
    data = buffer[tail];
    if (NULL == data) {
        return EWOULDBLOCK;
    }
    buffer[tail] = NULL;
    tail = NEXT(tail);
    return 0;
}

Both versions require a pre-allocated array for the data, my question is that is there any single-consumer single-producer lock-free queue implementation which uses malloc() to allocate space dynamically?

And another related question is, how can I measure exact overhead in queue synchronization? Such as how much time it takes of pthread_mutex_lock(), etc.

Answer 1

If you are worried about performance, adding malloc() to the mix won’t help things. And if you are not worried about performance, why not simply control access to the queue via a mutex. Have you actually measured the performance of such an implementation? It sounds to me as though you are going down the familar route of premature optimisation.