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);
}
"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));
});