#include "src/mc/mc_exit.hpp"
#include "src/mc/mc_private.hpp"
#include "src/mc/mc_record.hpp"
+#include "src/mc/remote/mc_protocol.h"
#include "src/mc/transition/Transition.hpp"
-#if SIMGRID_HAVE_STATEFUL_MC
-#include "src/mc/VisitedState.hpp"
-#endif
-
-#include "src/xbt/mmalloc/mmprivate.h"
+#include "xbt/asserts.h"
#include "xbt/log.h"
#include "xbt/string.hpp"
#include "xbt/sysdep.h"
xbt::signal<void(RemoteApp&)> DFSExplorer::on_log_state_signal;
-void DFSExplorer::check_non_termination(const State* current_state)
-{
-#if SIMGRID_HAVE_STATEFUL_MC
- for (auto const& state : stack_) {
- if (state->get_system_state()->equals_to(*current_state->get_system_state(),
- *get_remote_app().get_remote_process_memory())) {
- XBT_INFO("Non-progressive cycle: state %ld -> state %ld", state->get_num(), current_state->get_num());
- XBT_INFO("******************************************");
- XBT_INFO("*** NON-PROGRESSIVE CYCLE DETECTED ***");
- XBT_INFO("******************************************");
- XBT_INFO("Counter-example execution trace:");
- for (auto const& s : get_textual_trace())
- XBT_INFO(" %s", s.c_str());
- XBT_INFO("You can debug the problem (and see the whole details) by rerunning out of simgrid-mc with "
- "--cfg=model-check/replay:'%s'",
- get_record_trace().to_string().c_str());
- log_state();
-
- throw McError(ExitStatus::NON_TERMINATION);
- }
- }
-#endif
-}
-
RecordTrace DFSExplorer::get_record_trace() // override
{
RecordTrace res;
void DFSExplorer::restore_stack(std::shared_ptr<State> state)
{
stack_.clear();
+ execution_seq_ = odpor::Execution();
auto current_state = state;
stack_.emplace_front(current_state);
// condition corresponds to reaching initial state
stack_.emplace_front(current_state);
}
XBT_DEBUG("Replaced stack by %s", get_record_trace().to_string().c_str());
-
if (reduction_mode_ == ReductionMode::sdpor || reduction_mode_ == ReductionMode::odpor) {
- execution_seq_ = odpor::Execution();
-
- // NOTE: The outgoing transition for the top-most
- // state of the stack refers to that which was taken
- // as part of the last trace explored by the algorithm.
- // Thus, only the sequence of transitions leading up to,
- // but not including, the last state must be included
- // when reconstructing the Exploration for SDPOR.
- for (auto iter = stack_.begin(); iter != stack_.end() - 1 and iter != stack_.end(); ++iter) {
- const auto& state = *(iter);
- execution_seq_.push_transition(state->get_transition_out());
+ // NOTE: The outgoing transition for the top-most state of the stack refers to that which was taken
+ // as part of the last trace explored by the algorithm. Thus, only the sequence of transitions leading up to,
+ // but not including, the last state must be included when reconstructing the Exploration for SDPOR.
+ for (auto iter = std::next(stack_.begin()); iter != stack_.end(); ++iter) {
+ execution_seq_.push_transition((*iter)->get_transition_in());
}
+ XBT_DEBUG("Replaced SDPOR/ODPOR execution to reflect the new stack");
}
- XBT_DEBUG("Additionally replaced corresponding SDPOR execution stack");
}
void DFSExplorer::log_state() // override
on_log_state_signal(get_remote_app());
XBT_INFO("DFS exploration ended. %ld unique states visited; %lu backtracks (%lu transition replays, %lu states "
"visited overall)",
- State::get_expanded_states(), backtrack_count_, visited_states_count_,
- Transition::get_replayed_transitions());
+ State::get_expanded_states(), backtrack_count_, Transition::get_replayed_transitions(),
+ visited_states_count_);
Exploration::log_state();
}
XBT_ERROR("/!\\ Max depth of %d reached! THIS **WILL** BREAK the reduction, which is not sound "
"when stopping at a fixed depth /!\\",
_sg_mc_max_depth.get());
- XBT_ERROR("/!\\ If bad things happen, disable dpor with --cfg=model-check/reduction:none /!\\");
+ XBT_ERROR("/!\\ If bad things happen, disable the reduction with --cfg=model-check/reduction:none /!\\");
} else {
XBT_WARN("/!\\ Max depth reached ! /!\\ ");
}
continue;
}
-#if SIMGRID_HAVE_STATEFUL_MC
- // Backtrack if we are revisiting a state we saw previously while applying state-equality reduction
- if (visited_state_ != nullptr) {
- XBT_DEBUG("State already visited (equal to state %ld), exploration stopped on this path.",
- visited_state_->original_num_ == -1 ? visited_state_->num_ : visited_state_->original_num_);
-
- visited_state_ = nullptr;
- this->backtrack();
- continue;
- }
-#endif
-
if (reduction_mode_ == ReductionMode::odpor) {
- // In the case of ODPOR, the wakeup tree for this
- // state may be empty if we're exploring new territory
- // (rather than following the partial execution of a
- // wakeup tree). This corresponds to lines 9 to 13 of
+ // In the case of ODPOR, the wakeup tree for this state may be empty if we're exploring new territory
+ // (rather than following the partial execution of a wakeup tree). This corresponds to lines 9 to 13 of
// the ODPOR pseudocode
//
- // INVARIANT: The execution sequence should be consistent
- // with the state when seeding the tree. If the sequence
- // gets out of sync with the state, selection will not
- // work as we intend
+ // INVARIANT: The execution sequence should be consistent with the state when seeding the tree. If the sequence
+ // gets out of sync with the state, selection will not work as we intend
state->seed_wakeup_tree_if_needed(execution_seq_);
}
const aid_t next = reduction_mode_ == ReductionMode::odpor ? state->next_odpor_transition()
: std::get<0>(state->next_transition_guided());
- if (next < 0) { // If there is no more transition in the current state, backtrack.
+ if (next < 0 || not state->is_actor_enabled(next)) {
+ if (next >= 0) { // Actor is not enabled, then
+ XBT_DEBUG(
+ "Reduction %s wants to execute a disabled transition %s. If it's ODPOR, ReversibleRace is suboptimal.",
+ to_c_str(reduction_mode_), state->get_actors_list().at(next).get_transition()->to_string(true).c_str());
+ if (reduction_mode_ == ReductionMode::odpor) {
+ // Remove the disabled transition from the wakeup tree so that ODPOR doesn't try it again
+ state->remove_subtree_at_aid(next);
+ state->add_sleep_set(state->get_actors_list().at(next).get_transition());
+ } else {
+ xbt_assert(false, "Only ODPOR should be confident enought in itself to try executing a disabled transition");
+ }
+ }
+ // If there is no more transition in the current state (or if ODPOR picked an actor that is not enabled --
+ // ReversibleRace is an overapproximation), backtrace
XBT_VERB("%lu actors remain, but none of them need to be interleaved (depth %zu).", state->get_actor_count(),
stack_.size() + 1);
continue;
}
- if (_sg_mc_sleep_set && XBT_LOG_ISENABLED(mc_dfs, xbt_log_priority_verbose)) {
+ if (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());
+ for (const auto& [aid, transition] : state->get_sleep_set())
+ XBT_VERB(" <%ld,%s>", aid, transition->to_string().c_str());
}
+ auto todo = state->get_actors_list().at(next).get_transition();
+ XBT_DEBUG("wanna execute %ld: %.60s", next, todo->to_string().c_str());
+
/* Actually answer the request: let's execute the selected request (MCed does one step) */
- const auto executed_transition = state->execute_next(next, get_remote_app());
+ auto executed_transition = state->execute_next(next, get_remote_app());
on_transition_execute_signal(state->get_transition_out().get(), get_remote_app());
// If there are processes to interleave and the maximum depth has not been
// reached then perform one step of the exploration algorithm.
- XBT_VERB("Execute %ld: %.60s (stack depth: %zu, state: %ld, %zu interleaves)", state->get_transition_out()->aid_,
+ XBT_VERB("Executed %ld: %.60s (stack depth: %zu, state: %ld, %zu interleaves)", state->get_transition_out()->aid_,
state->get_transition_out()->to_string().c_str(), stack_.size(), state->get_num(), state->count_todo());
/* Create the new expanded state (copy the state of MCed into our MCer data) */
on_state_creation_signal(next_state.get(), get_remote_app());
if (reduction_mode_ == ReductionMode::odpor) {
- // With ODPOR, after taking a step forward, we must
- // assign a copy of that subtree to the next state.
+ // With ODPOR, after taking a step forward, we must assign a copy of that subtree to the next state.
//
- // NOTE: We only add actions to the sleep set AFTER
- // we've regenerated states. We must perform the search
- // fully down a single path before we consider adding
- // any elements to the sleep set according to the pseudocode
+ // NOTE: We only add actions to the sleep set AFTER we've regenerated states. We must perform the search
+ // fully down a single path before we consider adding any elements to the sleep set according to the pseudocode
next_state->sprout_tree_from_parent_state();
-
- // TODO: Consider what we have to do to handle transitions
- // with multiple possible executions. We probably have to re-insert
- // something into `state` and make note of that for later (opened_states_)
} else {
/* Sleep set procedure:
* adding the taken transition to the sleep set of the original state.
continue;
} else if (prev_state->get_transition_out()->depends(state->get_transition_out().get())) {
XBT_VERB("Dependent Transitions:");
- XBT_VERB(" %s (state=%ld)", prev_state->get_transition_out()->to_string().c_str(), prev_state->get_num());
- XBT_VERB(" %s (state=%ld)", state->get_transition_out()->to_string().c_str(), state->get_num());
+ XBT_VERB(" #%ld %s (state=%ld)", prev_state->get_transition_out()->aid_,
+ prev_state->get_transition_out()->to_string().c_str(), prev_state->get_num());
+ XBT_VERB(" #%ld %s (state=%ld)", state->get_transition_out()->aid_,
+ state->get_transition_out()->to_string().c_str(), state->get_num());
if (prev_state->is_actor_enabled(issuer_id)) {
if (not prev_state->is_actor_done(issuer_id)) {
break;
} else {
XBT_VERB("INDEPENDENT Transitions:");
- XBT_VERB(" %s (state=%ld)", prev_state->get_transition_out()->to_string().c_str(), prev_state->get_num());
- XBT_VERB(" %s (state=%ld)", state->get_transition_out()->to_string().c_str(), state->get_num());
+ XBT_VERB(" #%ld %s (state=%ld)", prev_state->get_transition_out()->aid_,
+ prev_state->get_transition_out()->to_string().c_str(), prev_state->get_num());
+ XBT_VERB(" #%ld %s (state=%ld)", state->get_transition_out()->aid_,
+ state->get_transition_out()->to_string().c_str(), state->get_num());
}
tmp_stack.pop_back();
}
/**
* SDPOR Source Set Procedure:
*
- * Find "reversible races" in the current execution `E` with respect
- * to the latest action `p`. For each such race, determine one thread
- * not contained in the backtrack set at the "race point" `r` which
- * "represents" the trace formed by first executing everything after
- * `r` that doesn't depend on it (`v := notdep(r, E)`) and then `p` to
+ * Find "reversible races" in the current execution `E` with respect to the latest action `p`. For each such race,
+ * determine one thread not contained in the backtrack set at the "race point" `r` which "represents" the trace
+ * formed by first executing everything after `r` that doesn't depend on it (`v := notdep(r, E)`) and then `p` to
* flip the race.
*
- * The intuition is that some subsequence of `v` may enable `p`, so
- * we want to be sure that search "in that direction"
+ * The intuition is that some subsequence of `v` may enable `p`, so we want to be sure that search "in that
+ * direction"
*/
- const aid_t p = executed_transition->aid_;
execution_seq_.push_transition(std::move(executed_transition));
- xbt_assert(execution_seq_.get_latest_event_handle().has_value(),
- "No events are contained in the SDPOR/OPDPOR execution "
- "even though one was just added");
+ xbt_assert(execution_seq_.get_latest_event_handle().has_value(), "No events are contained in the SDPOR execution "
+ "even though one was just added");
const auto next_E_p = execution_seq_.get_latest_event_handle().value();
- for (const auto racing_event_handle : execution_seq_.get_racing_events_of(next_E_p)) {
- // To determine if the race is reversible, we have to ensure
- // that actor `p` running `next_E_p` (viz. the event such that
- // `racing_event -> (E_p) next_E_p` and no other event
- // "happens-between" the two) is enabled in any equivalent
- // execution where `racing_event` happens before `next_E_p`.
- //
- // Importantly, it is equivalent to checking if in ANY
- // such equivalent execution sequence where `racing_event`
- // happens-before `next_E_p` that `p` is enabled in `pre(racing_event, E.p)`.
- // Thus it suffices to check THIS execution
- //
- // If the actor `p` is not enabled at s_[E'], it is not a *reversible* race
- const std::shared_ptr<State> prev_state = stack_[racing_event_handle];
- if (prev_state->is_actor_enabled(p)) {
- // NOTE: To incorporate the idea of attempting to select the "best"
- // backtrack point into SDPOR, instead of selecting the `first` initial,
- // we should instead compute all choices and decide which is best
- const std::optional<aid_t> q =
- execution_seq_.get_first_sdpor_initial_from(racing_event_handle, prev_state->get_backtrack_set());
- if (q.has_value()) {
- prev_state->consider_one(q.value());
- opened_states_.emplace_back(std::move(prev_state));
- }
+ for (const auto e_race : execution_seq_.get_reversible_races_of(next_E_p)) {
+ State* prev_state = stack_[e_race].get();
+ const auto choices = execution_seq_.get_missing_source_set_actors_from(e_race, prev_state->get_backtrack_set());
+ if (not choices.empty()) {
+ // NOTE: To incorporate the idea of attempting to select the "best" backtrack point into SDPOR, instead of
+ // selecting the `first` initial, we should instead compute all choices and decide which is best
+ //
+ // Here, we choose the actor with the lowest ID to ensure we get deterministic results
+ const auto q =
+ std::min_element(choices.begin(), choices.end(), [](const aid_t a1, const aid_t a2) { return a1 < a2; });
+ prev_state->consider_one(*q);
+ opened_states_.emplace_back(std::move(prev_state));
}
}
} else if (reduction_mode_ == ReductionMode::odpor) {
- // In the case of ODPOR, we simply observe the transition that was executed
- // until we've reached a maximal trace
+ // In the case of ODPOR, we simply observe the transition that was executed until we've reached a maximal trace
execution_seq_.push_transition(std::move(executed_transition));
}
if (stack_.back()->count_todo_multiples() > 0)
opened_states_.emplace_back(stack_.back());
- if (_sg_mc_termination)
- this->check_non_termination(next_state.get());
-
-#if SIMGRID_HAVE_STATEFUL_MC
- /* Check whether we already explored next_state in the past (but only if interested in state-equality reduction)
- */
- if (_sg_mc_max_visited_states > 0)
- visited_state_ = visited_states_.addVisitedState(next_state->get_num(), next_state.get(), get_remote_app());
-#endif
-
stack_.emplace_back(std::move(next_state));
/* If this is a new state (or if we don't care about state-equality reduction) */
- if (visited_state_ == nullptr) {
- /* Get an enabled process and insert it in the interleave set of the next state */
- if (reduction_mode_ == ReductionMode::dpor)
- stack_.back()->consider_best(); // Take only one transition if DPOR: others may be considered later if required
- else {
- stack_.back()->consider_all();
- }
-
- dot_output("\"%ld\" -> \"%ld\" [%s];\n", state->get_num(), stack_.back()->get_num(),
- state->get_transition_out()->dot_string().c_str());
-#if SIMGRID_HAVE_STATEFUL_MC
- } else {
- dot_output("\"%ld\" -> \"%ld\" [%s];\n", state->get_num(),
- visited_state_->original_num_ == -1 ? visited_state_->num_ : visited_state_->original_num_,
- state->get_transition_out()->dot_string().c_str());
-#endif
+ /* Get an enabled process and insert it in the interleave set of the next state */
+ if (reduction_mode_ == ReductionMode::dpor)
+ stack_.back()->consider_best(); // Take only one transition if DPOR: others may be considered later if required
+ else {
+ stack_.back()->consider_all();
}
+
+ dot_output("\"%ld\" -> \"%ld\" [%s];\n", state->get_num(), stack_.back()->get_num(),
+ state->get_transition_out()->dot_string().c_str());
}
log_state();
}
continue;
if (valid != current)
*valid = std::move(*current);
- if (best == end(opened_states_) || prio > best_prio) {
+ if (best == end(opened_states_) || prio < best_prio) {
best_prio = prio;
best = valid;
}
{
for (auto iter = stack_.rbegin(); iter != stack_.rend(); ++iter) {
const auto& state = *iter;
- state->do_odpor_backtrack_cleanup();
- if (!state->has_empty_tree()) {
+ state->do_odpor_unwind();
+ XBT_DEBUG("\tPerformed ODPOR 'clean-up'. Sleep set has:");
+ for (const auto& [aid, transition] : state->get_sleep_set())
+ XBT_DEBUG("\t <%ld,%s>", aid, transition->to_string().c_str());
+ if (not state->has_empty_tree()) {
return state;
}
}
- xbt_die("There are no more states for ODPOR");
return nullptr;
}
/**
* ODPOR Race Detection Procedure:
*
- * For each reversible race in the current execution, we
- * note if there are any continuations `C` equivalent to that which
- * would reverse the race that have already either a) been searched by ODPOR or
- * b) been *noted* to be searched by the wakeup tree at the
- * appropriate reversal point, either as `C` directly or
- * an as equivalent to `C` ("eventually looks like C", viz. the `~_E`
- * relation)
+ * For each reversible race in the current execution, we note if there are any continuations `C` equivalent to that
+ * which would reverse the race that have already either a) been searched by ODPOR or b) been *noted* to be searched
+ * by the wakeup tree at the appropriate reversal point, either as `C` directly or an as equivalent to `C`
+ * ("eventually looks like C", viz. the `~_E` relation)
*/
for (auto e_prime = static_cast<odpor::Execution::EventHandle>(0); e_prime <= last_event.value(); ++e_prime) {
- for (const auto e : execution_seq_.get_racing_events_of(e_prime)) {
- // To determine if the race is reversible, we have to ensure
- // that actor `p` running `e_i` (viz. the event such that
- // `racing_event -> (E_p) e_i` and no other event
- // "happens-between" the two) is enabled in any equivalent
- // execution where `racing_event` happens before `e_i`.
- //
- // Importantly, it is equivalent to checking if in ANY
- // such equivalent execution sequence where `racing_event`
- // happens-before `next_E_p` that `p` is enabled in `pre(racing_event, E.p)`.
- // Thus it suffices to check THIS execution
- //
- // If the actor `p` is not enabled at s_[E'], it is not a *reversible* race
- const aid_t p = execution_seq_.get_actor_with_handle(e_prime);
+ XBT_DEBUG("ODPOR: Now considering all possible race with `%u`", e_prime);
+ for (const auto e : execution_seq_.get_reversible_races_of(e_prime)) {
+ XBT_DEBUG("ODPOR: Reversible race detected between events `%u` and `%u`", e, e_prime);
State& prev_state = *stack_[e];
- if (prev_state.is_actor_enabled(p)) {
- const std::optional<odpor::PartialExecution> v =
- execution_seq_.get_odpor_extension_from(e, e_prime, prev_state);
- if (v.has_value()) {
- prev_state.mark_path_interesting_for_odpor(v.value(), execution_seq_.get_prefix_before(e));
+ if (const auto v = execution_seq_.get_odpor_extension_from(e, e_prime, prev_state); v.has_value()) {
+ switch (prev_state.insert_into_wakeup_tree(v.value(), execution_seq_.get_prefix_before(e))) {
+ case odpor::WakeupTree::InsertionResult::root: {
+ XBT_DEBUG("ODPOR: Reversible race with `%u`(%ld: %.20s) unaccounted for in the wakeup tree for "
+ "the execution prior to event `%u`(%ld: %.20s):",
+ e_prime, stack_[e_prime]->get_transition_out()->aid_,
+ stack_[e_prime]->get_transition_out()->to_string(true).c_str(), e,
+ prev_state.get_transition_out()->aid_,
+ prev_state.get_transition_out()->to_string(true).c_str());
+ break;
+ }
+ case odpor::WakeupTree::InsertionResult::interior_node: {
+ XBT_DEBUG("ODPOR: Reversible race with `%u` partially accounted for in the wakeup tree for "
+ "the execution prior to event `%u`:",
+ e_prime, e);
+ break;
+ }
+ case odpor::WakeupTree::InsertionResult::leaf: {
+ XBT_DEBUG("ODPOR: Reversible race with `%u` accounted for in the wakeup tree for "
+ "the execution prior to event `%u`:",
+ e_prime, e);
+ break;
+ }
+ }
+ for (const auto& seq : simgrid::mc::odpor::get_textual_trace(v.value())) {
+ XBT_DEBUG(" %s", seq.c_str());
}
+ } else {
+ XBT_DEBUG("ODPOR: Ignoring race: `sleep(E')` intersects `WI_[E'](v := notdep(%u, E))`", e);
+ XBT_DEBUG("Sleep set contains:");
+ for (const auto& [aid, transition] : prev_state.get_sleep_set())
+ XBT_DEBUG(" <%ld,%s>", aid, transition->to_string().c_str());
}
}
}
backtrack_count_++;
XBT_DEBUG("Backtracking to state#%ld", backtracking_point->get_num());
-#if SIMGRID_HAVE_STATEFUL_MC
- /* If asked to rollback on a state that has a snapshot, restore it */
- if (const auto* system_state = backtracking_point->get_system_state()) {
- system_state->restore(*get_remote_app().get_remote_process_memory());
- on_restore_system_state_signal(backtracking_point.get(), get_remote_app());
- this->restore_stack(backtracking_point);
- return;
- }
-#endif
-
// Search how to restore the backtracking point
- State* init_state = nullptr;
std::deque<Transition*> replay_recipe;
- for (auto* s = backtracking_point.get(); s != nullptr; s = s->get_parent_state().get()) {
-#if SIMGRID_HAVE_STATEFUL_MC
- if (s->get_system_state() != nullptr) { // Found a state that I can restore
- init_state = s;
- break;
- }
-#endif
+ for (const auto* s = backtracking_point.get(); s != nullptr; s = s->get_parent_state().get()) {
if (s->get_transition_in() != nullptr) // The root has no transition_in
replay_recipe.push_front(s->get_transition_in().get());
}
- // Restore the init_state, if any
- if (init_state != nullptr) {
-#if SIMGRID_HAVE_STATEFUL_MC
- const auto* system_state = init_state->get_system_state();
- system_state->restore(*get_remote_app().get_remote_process_memory());
- on_restore_system_state_signal(init_state, get_remote_app());
-#endif
- } else { // Restore the initial state if no intermediate state was found
- get_remote_app().restore_initial_state();
- on_restore_initial_state_signal(get_remote_app());
- }
+ // Restore the initial state if no intermediate state was found
+ get_remote_app().restore_initial_state();
+ on_restore_initial_state_signal(get_remote_app());
/* if no snapshot, we need to restore the initial state and replay the transitions */
/* Traverse the stack from the state at position start and re-execute the transitions */
this->restore_stack(backtracking_point);
}
-DFSExplorer::DFSExplorer(const std::vector<char*>& args, ReductionMode mode, bool need_memory_info)
- : Exploration(args, need_memory_info || _sg_mc_termination
-#if SIMGRID_HAVE_STATEFUL_MC
- || _sg_mc_checkpoint > 0
-#endif
- )
- , reduction_mode_(mode)
+DFSExplorer::DFSExplorer(const std::vector<char*>& args, ReductionMode mode) : Exploration(args), reduction_mode_(mode)
{
- if (_sg_mc_termination) {
- if (mode != ReductionMode::none) {
- XBT_INFO("Check non progressive cycles (turning DPOR off)");
- reduction_mode_ = ReductionMode::none;
- } else {
- XBT_INFO("Check non progressive cycles");
- }
- } else
- XBT_INFO("Start a DFS exploration. Reduction is: %s.", to_c_str(reduction_mode_));
+ XBT_INFO("Start a DFS exploration. Reduction is: %s.", to_c_str(reduction_mode_));
auto initial_state = std::make_shared<State>(get_remote_app());
