add thread choosing in switch func
authorDerek Yeh <djyeh@plrg-1.ics.uci.edu>
Fri, 24 Jul 2020 06:00:55 +0000 (23:00 -0700)
committerDerek Yeh <djyeh@plrg-1.ics.uci.edu>
Fri, 24 Jul 2020 06:00:55 +0000 (23:00 -0700)
model.cc
model.h

index 0493e7e..ad2e0d9 100644 (file)
--- a/model.cc
+++ b/model.cc
@@ -365,14 +365,7 @@ uint64_t ModelChecker::switch_thread(ModelAction *act)
        }
 
        old->set_pending(act);
-       //Thread *next;
-       /*do {
-               curr_thread_num++;
-               thread_id_t tid = int_to_id(curr_thread_num);
-               next = get_thread(tid);
 
-       } while (next->is_model_thread() || next->is_complete() || next->get_pending() && curr_thread_num < get_num_threads()); 
-       */
        Thread *next = NULL;
        curr_thread_num++;
        while (curr_thread_num < get_num_threads()) {
@@ -384,14 +377,38 @@ uint64_t ModelChecker::switch_thread(ModelAction *act)
        }
        if (curr_thread_num < get_num_threads()) {
                scheduler->set_current_thread(next);
+               if (old->is_waiting_on(old))
+                       assert_bug("Deadlock detected (thread %u)", curr_thread_num);
+
+               ModelAction *act = old->get_pending();
+               
+               if (act && execution->is_enabled(old) && !execution->check_action_enabled(act)) {
+                       scheduler->sleep(old);
+               }
+               if (!thread_chosen && act && execution->is_enabled(old) && (old->get_state() != THREAD_BLOCKED) ) {
+                       if (act->is_write()) {
+                               std::memory_order order = act->get_mo();
+                               if (order == std::memory_order_relaxed || \
+                                               order == std::memory_order_release) {
+                                       chosen_thread = old;
+                                       thread_chosen = true;
+                               }
+                       } else if (act->get_type() == THREAD_CREATE || \
+                                                               act->get_type() == PTHREAD_CREATE || \
+                                                               act->get_type() == THREAD_START || \
+                                                               act->get_type() == THREAD_FINISH) {
+                               chosen_thread = old;
+                               thread_chosen = true;
+                       }
+               }
+
                if (Thread::swap(old, next) < 0) {
                        perror("swap threads");
                        exit(EXIT_FAILURE);
-               }
-               if (next->is_waiting_on(next))
-                       assert_bug("Deadlock detected (thread %u)", curr_thread_num);
+               }               
        } else {
                scheduler->set_current_thread(NULL);
+
                if (Thread::swap(old, &system_context) < 0) {
                        perror("swap threads");
                        exit(EXIT_FAILURE);
@@ -430,8 +447,8 @@ void ModelChecker::run()
        initstate(423121, random_state, sizeof(random_state));
        modelclock_t checkfree = params.checkthreshold;
        for(int exec = 0;exec < params.maxexecutions;exec++) {
-               Thread * t = init_thread;
-
+               chosen_thread = init_thread;
+               thread_chosen = false;
                do {
                        /* Check whether we need to free model actions. */
 
@@ -463,15 +480,15 @@ void ModelChecker::run()
                        }
                        */
                        /* Don't schedule threads which should be disabled */
-                       for (unsigned int i = 0;i < get_num_threads();i++) {
+                       /*for (unsigned int i = 0;i < get_num_threads();i++) {
                                Thread *th = get_thread(int_to_id(i));
                                ModelAction *act = th->get_pending();
                                if (act && execution->is_enabled(th) && !execution->check_action_enabled(act)) {
                                        scheduler->sleep(th);
                                }
                        }
-
-                       for (unsigned int i = 1;i < get_num_threads();i++) {
+                       */
+                       /*for (unsigned int i = 1;i < get_num_threads();i++) {
                                Thread *th = get_thread(int_to_id(i));
                                ModelAction *act = th->get_pending();
                                if (act && execution->is_enabled(th) && (th->get_state() != THREAD_BLOCKED) ) {
@@ -491,27 +508,27 @@ void ModelChecker::run()
                                        }
                                }
                        }
-
+                       */
                        /* Catch assertions from prior take_step or from
                        * between-ModelAction bugs (e.g., data races) */
 
                        if (execution->has_asserted())
                                break;
-                       if (!t)
-                               t = get_next_thread();
-                       if (!t || t->is_model_thread())
+                       if (!chosen_thread)
+                               chosen_thread = get_next_thread();
+                       if (!chosen_thread || chosen_thread->is_model_thread())
                                break;
-                       if (t->just_woken_up()) {
-                               t->set_wakeup_state(false);
-                               t->set_pending(NULL);
-                               t = NULL;
+                       if (chosen_thread->just_woken_up()) {
+                               chosen_thread->set_wakeup_state(false);
+                               chosen_thread->set_pending(NULL);
+                               chosen_thread = NULL;
                                continue;       // Allow this thread to stash the next pending action
                        }
 
                        /* Consume the next action for a Thread */
-                       ModelAction *curr = t->get_pending();
-                       t->set_pending(NULL);
-                       t = execution->take_step(curr);
+                       ModelAction *curr = chosen_thread->get_pending();
+                       chosen_thread->set_pending(NULL);
+                       chosen_thread = execution->take_step(curr);
                } while (!should_terminate_execution());
                finish_execution((exec+1) < params.maxexecutions);
                //restore random number generator state after rollback
diff --git a/model.h b/model.h
index 8a2f9c6..ed364b1 100644 (file)
--- a/model.h
+++ b/model.h
@@ -80,6 +80,10 @@ private:
 
        unsigned int curr_thread_num;
 
+       Thread * chosen_thread;
+
+       bool thread_chosen;
+
        unsigned int get_num_threads() const;
 
        void finish_execution(bool moreexecutions);