RecordTrace DFSExplorer::get_record_trace() // override
{
- RecordTrace res;
- for (auto const& state : stack_)
- res.push_back(state->get_transition());
- return res;
+ return get_record_trace_of_stack(stack_);
}
-RecordTrace get_record_trace_of_stack(stack_t stack)
+/* Usefull to show debug information */
+RecordTrace DFSExplorer::get_record_trace_of_stack(stack_t stack)
{
RecordTrace res;
for (auto const& state : stack)
Exploration::log_state();
}
+/* Copy a given stack by deep-copying it at the State level : this is required so we can backtrack at different
+ * points without interacting with the stacks in the opened_states_ waiting for their turn. On the other hand,
+ * the exploration of one stack in opened_states_ could only slightly modify the sleep set of another stack in
+ * opened_states_, so it is only a slight waste of performance in the exploration. */
void DFSExplorer::add_to_opened_states(stack_t stack)
{
stack_t tmp_stack;
for (auto& state : stack)
tmp_stack.push_back(std::make_shared<State>(State(*state)));
- opened_states_.emplace_back(tmp_stack);
+ opened_states_.emplace(tmp_stack);
}
void DFSExplorer::run()
}
// Search for the next transition
- // next_transition returns a pair<aid_t, double> in case we want to consider multiple state
+ // next_transition returns a pair<aid_t, double> in case we want to consider multiple state (eg. during backtrack)
auto [next, _] = state->next_transition_guided();
if (next < 0) { // If there is no more transition in the current state, backtrack.
this->backtrack();
continue;
}
+
if (_sg_mc_sleep_set && XBT_LOG_ISENABLED(mc_dfs, xbt_log_priority_verbose)) {
XBT_VERB("Sleep set actually containing:");
for (auto& [aid, transition] : state->get_sleep_set())
XBT_VERB(" <%ld,%s>", aid, transition.to_string().c_str());
}
- // if (stack_.back()->count_todo_multiples() <= 1)
- // add_to_opened_states(stack_);
-
/* Actually answer the request: let's execute the selected request (MCed does one step) */
state->execute_next(next, get_remote_app());
on_transition_execute_signal(state->get_transition(), get_remote_app());
XBT_DEBUG("Actor %ld is not enabled: DPOR may be failing. To stay sound, we are marking every enabled "
"transition as todo",
issuer_id);
- prev_state->consider_all();
- add_to_opened_states(tmp_stack);
+ if (prev_state->consider_all() >
+ 0) // If we ended up marking at least a transition, explore it at some point
+ add_to_opened_states(tmp_stack);
}
break;
} else {
}
}
+ // Before leaving that state, if the transition we just took can be taken multiple times, we
+ // need to give it to the opened states
+ if (stack_.back()->count_todo_multiples() > 0)
+ add_to_opened_states(stack_);
+
if (_sg_mc_termination)
this->check_non_termination(next_state.get());
else {
stack_.back()->consider_all();
}
- if (stack_.back()->count_todo_multiples() > 1)
- add_to_opened_states(stack_);
+
dot_output("\"%ld\" -> \"%ld\" [%s];\n", state->get_num(), stack_.back()->get_num(),
state->get_transition()->dot_string().c_str());
} else
visited_state_->original_num_ == -1 ? visited_state_->num_ : visited_state_->original_num_,
state->get_transition()->dot_string().c_str());
}
-
log_state();
}
void DFSExplorer::backtrack()
{
- backtrack_count_++;
XBT_VERB("Backtracking from %s", get_record_trace().to_string().c_str());
- XBT_DEBUG("%ld alternatives are yet to be explored:", opened_states_.size());
- for (auto& stack : opened_states_)
- XBT_DEBUG("--> %s", get_record_trace_of_stack(stack).to_string().c_str());
+ XBT_DEBUG("%lu alternatives are yet to be explored:", opened_states_.size());
+
on_backtracking_signal(get_remote_app());
get_remote_app().check_deadlock();
// if no backtracking point, then set the stack_ to empty so we can end the exploration
- if (opened_states_.size() == 0) {
+ if (opened_states_.empty()) {
stack_ = std::list<std::shared_ptr<State>>();
return;
}
- /* We may backtrack from somewhere either because it's leaf, or because every enabled process are in done/sleep set.
- * In the first case, we need to remove the last transition corresponding to the Finalize */
- if (stack_.back()->get_transition()->aid_ == 0)
- stack_.pop_back();
-
- stack_t backtrack;
- double min_dist = std::numeric_limits<double>::infinity();
- aid_t min_aid = -1;
- for (auto iter = opened_states_.begin(); iter != opened_states_.end();) {
- auto [aid, dist] = (*iter).back()->next_transition_guided();
- if (aid == -1) { // happens if no actors are todo anymore in this transition
- iter = opened_states_.erase(iter);
- continue;
- }
- if (dist < min_dist) {
- min_dist = dist;
- min_aid = aid;
- backtrack = (*iter);
- }
- iter++;
- }
+ stack_t backtrack = opened_states_.top(); // Take the point with smallest distance
+ opened_states_.pop();
- if (min_aid == -1) {
- stack_ = std::list<std::shared_ptr<State>>();
+ // if the smallest distance corresponded to no enable actor, remove this and let the
+ // exploration ask again for a backtrack
+ if (backtrack.back()->next_transition_guided().first == -1)
return;
- }
- if (backtrack.back()->count_todo_multiples() <= 1)
- opened_states_.remove(backtrack);
+ // We found a real backtracking point, let's go to it
+ backtrack_count_++;
/* If asked to rollback on a state that has a snapshot, restore it */
State* last_state = backtrack.back().get();
