diff --git a/main.cpp b/main.cpp index 2912aad..1874018 100644 --- a/main.cpp +++ b/main.cpp @@ -5,6 +5,7 @@ #include // size_t #include // memset +#include #include // cout #include // vector @@ -52,6 +53,8 @@ void *thread_task_increment(const struct thread_data &thread) { << "! (inside run loop, before mutex)" << std::endl; } + usleep(rand() % 20); + // mutex { @@ -60,6 +63,7 @@ void *thread_task_increment(const struct thread_data &thread) { ; // say we want the mutex (*thread.wants_mutex) = true; + usleep(rand() % 20); // block until we have the mutex while (!*thread.has_mutex) ; @@ -69,6 +73,8 @@ void *thread_task_increment(const struct thread_data &thread) { std::cout << "Hello from thread " << thread.id << "! (inside run loop, inside mutex)" << std::endl; + usleep(rand() % 20); + *static_cast(thread.data) += 1; // tell the thread manager we don't need the mutex @@ -123,9 +129,11 @@ void do_threading(struct thread_group threads) { // spawn threads (none will enter the mutex yet) for (size_t tid = 0; tid < threads.total_threads; ++tid) { + usleep(rand() % 20); pthread_create(&my_pthreads[tid], NULL, reinterpret_cast(thread_task_increment), &thread_data[tid]); + usleep(rand() % 20); } std::cout << "Threads have been spawned." << std::endl; @@ -133,14 +141,17 @@ void do_threading(struct thread_group threads) { // loop until all threads are done for (size_t finished_threads = 0; finished_threads < threads.total_threads;) { + usleep(rand() % 20); // TODO: make sure we cycle the mutex through threads round-robin style // hand off the mutex to threads that want it for (size_t tid_wants = 0; tid_wants < threads.total_threads; ++tid_wants) { + usleep(rand() % 20); if (threads.wants_mutex[tid_wants]) { // in case the mutex isn't used at all bool mutex_was_found = false; + usleep(rand() % 20); // find which thread has the mutex and hand it off if it's done for (size_t tid_has = 0; tid_has < threads.total_threads; ++tid_has) { @@ -148,16 +159,22 @@ void do_threading(struct thread_group threads) { if (threads.has_mutex[tid_has]) { // we found who has the mutex! mutex_was_found = true; + usleep(rand() % 20); // is the thread still using the mutex? if (!threads.wants_mutex[tid_has]) { + usleep(rand() % 20); // take the mutex from the thread that has it threads.has_mutex[tid_has] = false; + usleep(rand() % 20); threads.can_ask_for_mutex[tid_has] = true; + usleep(rand() % 20); // give the mutex to the thread that wants it threads.can_ask_for_mutex[tid_wants] = false; + usleep(rand() % 20); threads.has_mutex[tid_wants] = true; + usleep(rand() % 20); } break; // no need to look at the rest if we found who has the mutex @@ -166,8 +183,10 @@ void do_threading(struct thread_group threads) { // give the thread the mutex if it wasn't found to be in use if (!mutex_was_found) { + usleep(rand() % 20); threads.has_mutex[tid_wants] = true; } + usleep(rand() % 20); } } @@ -176,6 +195,7 @@ void do_threading(struct thread_group threads) { for (size_t tid = 0; tid < threads.total_threads; ++tid) { if (threads.threads_finished[tid]) finished_threads += 1; + usleep(rand() % 20); } } @@ -190,6 +210,8 @@ void do_threading(struct thread_group threads) { int main(void) { struct thread_group mythreads; + srand(time(NULL)); + // the count int count = 0;