namespace simgrid::mc::udpor {
-UdporChecker::UdporChecker(const std::vector<char*>& args) : Exploration(args, true) {}
+UdporChecker::UdporChecker(const std::vector<char*>& args) : Exploration(args) {}
void UdporChecker::run()
{
// possibility is that we've finished running everything, and
// we wouldn't be in deadlock then)
if (enC.empty()) {
- XBT_VERB("Maximal configuration detected. Checking for deadlock...");
+ XBT_VERB("**************************");
+ XBT_VERB("*** TRACE INVESTIGATED ***");
+ XBT_VERB("**************************");
+ XBT_VERB("Execution sequence:");
+ for (auto const& s : get_textual_trace())
+ XBT_VERB(" %s", s.c_str());
get_remote_app().check_deadlock();
}
// that we are searching again from `state(C)`. While the
// stack of states is properly adjusted to represent
// `state(C)` all together, the RemoteApp is currently sitting
- // at some *future* state with resepct to `state(C)` since the
- // recursive calls have moved it there.
+ // at some *future* state with respect to `state(C)` since the
+ // recursive calls had moved it there.
restore_program_state_with_current_stack();
// Explore(C, D + {e}, J \ C)
EventSet exC = prev_exC;
exC.remove(e_cur);
+ // IMPORTANT NOTE: In order to have deterministic results, we need to process
+ // the actors in a deterministic manner so that events are discovered by
+ // UDPOR in a deterministic order. The processing done here always processes
+ // actors in a consistent order since `std::map` is by-default ordered using
+ // `std::less<Key>` (see the return type of `State::get_actors_list()`)
for (const auto& [aid, actor_state] : stateC.get_actors_list()) {
- for (const auto& transition : actor_state.get_enabled_transitions()) {
- XBT_DEBUG("\t Considering partial extension for %s", transition->to_string().c_str());
- EventSet extension = ExtensionSetCalculator::partially_extend(C, &unfolding, transition);
- exC.form_union(extension);
+ const auto& enabled_transitions = actor_state.get_enabled_transitions();
+ if (enabled_transitions.empty()) {
+ XBT_DEBUG("\t Actor `%ld` is disabled: no partial extensions need to be considered", aid);
+ } else {
+ XBT_DEBUG("\t Actor `%ld` is enabled", aid);
+ for (const auto& transition : enabled_transitions) {
+ XBT_DEBUG("\t Considering partial extension for %s", transition->to_string().c_str());
+ EventSet extension = ExtensionSetCalculator::partially_extend(C, &unfolding, transition);
+ exC.form_union(extension);
+ }
}
}
return exC;
EventSet UdporChecker::compute_enC(const Configuration& C, const EventSet& exC) const
{
EventSet enC;
- for (const auto e : exC) {
+ for (const auto* e : exC) {
if (C.is_compatible_with(e)) {
enC.insert(e);
}
for (const std::unique_ptr<State>& state : state_stack) {
if (state == state_stack.back()) /* If we are arrived on the target state, don't replay the outgoing transition */
break;
- state->get_transition()->replay(get_remote_app());
+ state->get_transition_out()->replay(get_remote_app());
}
}
"empty before attempting to select an event from it?");
}
+ // UDPOR's exploration is non-deterministic (as is DPOR's)
+ // in the sense that at any given point there may
+ // be multiple paths that can be followed. The correctness and optimality
+ // of the algorithm remains unaffected by the route taken by UDPOR when
+ // given multiple choices; but to ensure that SimGrid itself has deterministic
+ // behavior on all platforms, we always pick events with lower id's
+ // to ensure we explore the unfolding deterministically.
if (A.empty()) {
- return const_cast<UnfoldingEvent*>(*(enC.begin()));
- }
-
- for (const auto& event : A) {
- if (enC.contains(event)) {
- return const_cast<UnfoldingEvent*>(event);
- }
+ const auto min_event = std::min_element(enC.begin(), enC.end(),
+ [](const auto e1, const auto e2) { return e1->get_id() < e2->get_id(); });
+ return const_cast<UnfoldingEvent*>(*min_event);
+ } else {
+ const auto intersection = A.make_intersection(enC);
+ const auto min_event = std::min_element(intersection.begin(), intersection.end(),
+ [](const auto e1, const auto e2) { return e1->get_id() < e2->get_id(); });
+ return const_cast<UnfoldingEvent*>(*min_event);
}
- return nullptr;
}
void UdporChecker::clean_up_explore(const UnfoldingEvent* e, const Configuration& C, const EventSet& D)
// "U (complicated expression)" portion
const EventSet conflict_union = std::accumulate(
- C_union_D.begin(), C_union_D.end(), EventSet(), [&](const EventSet acc, const UnfoldingEvent* e_prime) {
+ C_union_D.begin(), C_union_D.end(), EventSet(), [&](const EventSet& acc, const UnfoldingEvent* e_prime) {
return acc.make_union(unfolding.get_immediate_conflicts_of(e_prime));
});
XBT_DEBUG("Moving {%s} from U to G...", to_remove.to_string().c_str());
clean_up_set.form_union(to_remove);
}
- // TODO: We compute everything... but we don't actually
- // remove anything yet. This is a workaround until
- // we figure out how to deal with the fact that the previous
+
+ // TODO: We still perhaps need to
+ // figure out how to deal with the fact that the previous
// extension sets computed for past configurations
// contain events that may be removed from `U`. Perhaps
// it would be best to keep them around forever (they
// more efficient (we have to search all of `U` for such conflicts,
// and there would be no reason to search those events
// that UDPOR has marked as no longer being important)
- //
- // this->unfolding.remove(clean_up_set);
+ // For now, there appear to be no "obvious" issues (although
+ // UDPOR's behavior is often far from obvious...)
+ this->unfolding.mark_finished(clean_up_set);
}
RecordTrace UdporChecker::get_record_trace()
{
RecordTrace res;
for (auto const& state : state_stack)
- res.push_back(state->get_transition());
+ res.push_back(state->get_transition_out().get());
return res;
}
-std::vector<std::string> UdporChecker::get_textual_trace()
-{
- std::vector<std::string> trace;
- for (auto const& state : state_stack) {
- const auto* t = state->get_transition();
- trace.push_back(xbt::string_printf("%ld: %s", t->aid_, t->to_string().c_str()));
- }
- return trace;
-}
-
} // namespace simgrid::mc::udpor
namespace simgrid::mc {