PowerUser/mutex-cpp
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mutex: add random sleep intervals to test stability

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PowerUser64 2024-11-19 17:52:18 -08:00
parent 4a2c82247e
commit 1043680b19
1 changed files with 17 additions and 17 deletions
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34
main.cpp
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@ -53,7 +53,7 @@ void *thread_task_increment(const struct thread_data &thread) {
<< "! (inside run loop, before mutex)" << std::endl; << "! (inside run loop, before mutex)" << std::endl;
} }
usleep(rand() % 20); usleep(rand() % 200);
// mutex // mutex
{ {
@ -63,7 +63,7 @@ void *thread_task_increment(const struct thread_data &thread) {
; ;
// say we want the mutex // say we want the mutex
(*thread.wants_mutex) = true; (*thread.wants_mutex) = true;
usleep(rand() % 20); usleep(rand() % 200);
// block until we have the mutex // block until we have the mutex
while (!*thread.has_mutex) while (!*thread.has_mutex)
; ;
@ -73,7 +73,7 @@ void *thread_task_increment(const struct thread_data &thread) {
std::cout << "Hello from thread " << thread.id std::cout << "Hello from thread " << thread.id
<< "! (inside run loop, inside mutex)" << std::endl; << "! (inside run loop, inside mutex)" << std::endl;
usleep(rand() % 20); usleep(rand() % 200);
*static_cast<int *>(thread.data) += 1; *static_cast<int *>(thread.data) += 1;
@ -129,11 +129,11 @@ void do_threading(struct thread_group threads) {
// spawn threads (none will enter the mutex yet) // spawn threads (none will enter the mutex yet)
for (size_t tid = 0; tid < threads.total_threads; ++tid) { for (size_t tid = 0; tid < threads.total_threads; ++tid) {
usleep(rand() % 20); usleep(rand() % 200);
pthread_create(&my_pthreads[tid], NULL, pthread_create(&my_pthreads[tid], NULL,
reinterpret_cast<PthreadFun>(thread_task_increment), reinterpret_cast<PthreadFun>(thread_task_increment),
&thread_data[tid]); &thread_data[tid]);
usleep(rand() % 20); usleep(rand() % 200);
} }
std::cout << "Threads have been spawned." << std::endl; std::cout << "Threads have been spawned." << std::endl;
@ -141,17 +141,17 @@ void do_threading(struct thread_group threads) {
// loop until all threads are done // loop until all threads are done
for (size_t finished_threads = 0; finished_threads < threads.total_threads;) { for (size_t finished_threads = 0; finished_threads < threads.total_threads;) {
usleep(rand() % 20); usleep(rand() % 200);
// TODO: make sure we cycle the mutex through threads round-robin style // TODO: make sure we cycle the mutex through threads round-robin style
// hand off the mutex to threads that want it // hand off the mutex to threads that want it
for (size_t tid_wants = 0; tid_wants < threads.total_threads; ++tid_wants) { for (size_t tid_wants = 0; tid_wants < threads.total_threads; ++tid_wants) {
usleep(rand() % 20); usleep(rand() % 200);
if (threads.wants_mutex[tid_wants]) { if (threads.wants_mutex[tid_wants]) {
// in case the mutex isn't used at all // in case the mutex isn't used at all
bool mutex_was_found = false; bool mutex_was_found = false;
usleep(rand() % 20); usleep(rand() % 200);
// find which thread has the mutex and hand it off if it's done // 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) { for (size_t tid_has = 0; tid_has < threads.total_threads; ++tid_has) {
@ -159,22 +159,22 @@ void do_threading(struct thread_group threads) {
if (threads.has_mutex[tid_has]) { if (threads.has_mutex[tid_has]) {
// we found who has the mutex! // we found who has the mutex!
mutex_was_found = true; mutex_was_found = true;
usleep(rand() % 20); usleep(rand() % 200);
// is the thread still using the mutex? // is the thread still using the mutex?
if (!threads.wants_mutex[tid_has]) { if (!threads.wants_mutex[tid_has]) {
usleep(rand() % 20); usleep(rand() % 200);
// take the mutex from the thread that has it // take the mutex from the thread that has it
threads.has_mutex[tid_has] = false; threads.has_mutex[tid_has] = false;
usleep(rand() % 20); usleep(rand() % 200);
threads.can_ask_for_mutex[tid_has] = true; threads.can_ask_for_mutex[tid_has] = true;
usleep(rand() % 20); usleep(rand() % 200);
// give the mutex to the thread that wants it // give the mutex to the thread that wants it
threads.can_ask_for_mutex[tid_wants] = false; threads.can_ask_for_mutex[tid_wants] = false;
usleep(rand() % 20); usleep(rand() % 200);
threads.has_mutex[tid_wants] = true; threads.has_mutex[tid_wants] = true;
usleep(rand() % 20); usleep(rand() % 200);
} }
break; // no need to look at the rest if we found who has the mutex break; // no need to look at the rest if we found who has the mutex
@ -183,10 +183,10 @@ void do_threading(struct thread_group threads) {
// give the thread the mutex if it wasn't found to be in use // give the thread the mutex if it wasn't found to be in use
if (!mutex_was_found) { if (!mutex_was_found) {
usleep(rand() % 20); usleep(rand() % 200);
threads.has_mutex[tid_wants] = true; threads.has_mutex[tid_wants] = true;
} }
usleep(rand() % 20); usleep(rand() % 200);
} }
} }
@ -195,7 +195,7 @@ void do_threading(struct thread_group threads) {
for (size_t tid = 0; tid < threads.total_threads; ++tid) { for (size_t tid = 0; tid < threads.total_threads; ++tid) {
if (threads.threads_finished[tid]) if (threads.threads_finished[tid])
finished_threads += 1; finished_threads += 1;
usleep(rand() % 20); usleep(rand() % 200);
} }
} }