X-Git-Url: http://info.iut-bm.univ-fcomte.fr/pub/gitweb/simgrid.git/blobdiff_plain/54b931da542487537ab6ec3c4c8f5a9ec06822a7..4436a8d7307514469bb78664ea83359da0d57b4a:/src/mc/explo/DFSExplorer.cpp diff --git a/src/mc/explo/DFSExplorer.cpp b/src/mc/explo/DFSExplorer.cpp index 9ef0daf463..4e9c03b8c3 100644 --- a/src/mc/explo/DFSExplorer.cpp +++ b/src/mc/explo/DFSExplorer.cpp @@ -1,18 +1,22 @@ -/* Copyright (c) 2016-2022. The SimGrid Team. All rights reserved. */ +/* Copyright (c) 2016-2023. The SimGrid Team. All rights reserved. */ /* This program is free software; you can redistribute it and/or modify it * under the terms of the license (GNU LGPL) which comes with this package. */ #include "src/mc/explo/DFSExplorer.hpp" -#include "src/mc/VisitedState.hpp" #include "src/mc/mc_config.hpp" #include "src/mc/mc_exit.hpp" #include "src/mc/mc_private.hpp" #include "src/mc/mc_record.hpp" #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/log.h" +#include "xbt/string.hpp" #include "xbt/sysdep.h" #include @@ -40,47 +44,69 @@ xbt::signal DFSExplorer::on_log_state_signal; void DFSExplorer::check_non_termination(const State* current_state) { - for (auto state = stack_.rbegin(); state != stack_.rend(); ++state) - if (*(*state)->get_system_state() == *current_state->get_system_state()) { - XBT_INFO("Non-progressive cycle: state %ld -> state %ld", (*state)->get_num(), current_state->get_num()); +#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("Path = %s", get_record_trace().to_string().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 TerminationError(); + throw McError(ExitStatus::NON_TERMINATION); } + } +#endif } RecordTrace DFSExplorer::get_record_trace() // override { RecordTrace res; - for (auto const& state : stack_) - res.push_back(state->get_transition()); + for (auto const& transition : stack_.back()->get_recipe()) + res.push_back(transition); + res.push_back(stack_.back()->get_transition_out()); return res; } std::vector DFSExplorer::get_textual_trace() // override { std::vector trace; - for (auto const& state : stack_) { - const auto* t = state->get_transition(); - trace.push_back(xbt::string_printf("%ld: %s", t->aid_, t->to_string().c_str())); + for (auto const& transition : stack_.back()->get_recipe()) { + trace.push_back(xbt::string_printf("%ld: %s", transition->aid_, transition->to_string().c_str())); } + if (const auto* trans = stack_.back()->get_transition_out(); trans != nullptr) + trace.push_back(xbt::string_printf("%ld: %s", trans->aid_, trans->to_string().c_str())); return trace; } +void DFSExplorer::restore_stack(std::shared_ptr state) +{ + stack_.clear(); + auto current_state = state; + stack_.emplace_front(current_state); + // condition corresponds to reaching initial state + while (current_state->get_parent_state() != nullptr) { + current_state = current_state->get_parent_state(); + stack_.emplace_front(current_state); + } + XBT_DEBUG("Replaced stack by %s", get_record_trace().to_string().c_str()); +} + void DFSExplorer::log_state() // override { on_log_state_signal(get_remote_app()); - XBT_INFO("DFS exploration ended. %ld unique states visited; %ld backtracks (%lu transition replays, %lu states " + XBT_INFO("DFS exploration ended. %ld unique states visited; %lu backtracks (%lu transition replays, %lu states " "visited overall)", - State::get_expanded_states(), backtrack_count_, mc_model_checker->get_visited_states(), + State::get_expanded_states(), backtrack_count_, visited_states_count_, Transition::get_replayed_transitions()); + Exploration::log_state(); } void DFSExplorer::run() @@ -92,13 +118,13 @@ void DFSExplorer::run() while (not stack_.empty()) { /* Get current state */ - State* state = stack_.back().get(); + auto state = stack_.back(); XBT_DEBUG("**************************************************"); - XBT_DEBUG("Exploration depth=%zu (state:%ld; %zu interleaves)", stack_.size(), state->get_num(), + XBT_DEBUG("Exploration depth=%zu (state:#%ld; %zu interleaves todo)", stack_.size(), state->get_num(), state->count_todo()); - mc_model_checker->inc_visited_states(); + visited_states_count_++; // Backtrack if we reached the maximum depth if (stack_.size() > (std::size_t)_sg_mc_max_depth) { @@ -112,157 +138,225 @@ void DFSExplorer::run() continue; } - // Backtrack if we are revisiting a state we saw previously +#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_->original_num_ == -1 ? visited_state_->num_ : visited_state_->original_num_); visited_state_ = nullptr; this->backtrack(); continue; } +#endif // Search for the next transition - int next = state->next_transition(); + // next_transition returns a pair 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. - XBT_DEBUG("There remains %d actors, but none to interleave (depth %zu).", state->get_actor_count(), - stack_.size() + 1); + XBT_VERB("%lu actors remain, but none of them need to be interleaved (depth %zu).", state->get_actor_count(), + stack_.size() + 1); if (state->get_actor_count() == 0) { - mc_model_checker->finalize_app(); + get_remote_app().finalize_app(); XBT_VERB("Execution came to an end at %s (state: %ld, depth: %zu)", get_record_trace().to_string().c_str(), state->get_num(), stack_.size()); } + 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()); + } + /* Actually answer the request: let's execute the selected request (MCed does one step) */ - state->execute_next(next); - on_transition_execute_signal(state->get_transition(), get_remote_app()); + state->execute_next(next, get_remote_app()); + on_transition_execute_signal(state->get_transition_out(), 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()->aid_, - state->get_transition()->to_string().c_str(), stack_.size(), state->get_num(), state->count_todo()); + XBT_VERB("Execute %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) */ - auto next_state = std::make_unique(get_remote_app()); + auto next_state = std::make_shared(get_remote_app(), state); on_state_creation_signal(next_state.get(), get_remote_app()); + /* Sleep set procedure: + * adding the taken transition to the sleep set of the original state. + * Since the parent sleep set is used to compute the child sleep set, this need to be + * done after next_state creation */ + XBT_DEBUG("Marking Transition >>%s<< of process %ld done and adding it to the sleep set", + state->get_transition_out()->to_string().c_str(), state->get_transition_out()->aid_); + state->add_sleep_set(state->get_transition_out()); // Actors are marked done when they are considerd in ActorState + + /* DPOR persistent set procedure: + * for each new transition considered, check if it depends on any other previous transition executed before it + * on another process. If there exists one, find the more recent, and add its process to the interleave set. + * If the process is not enabled at this point, then add every enabled process to the interleave */ + if (reduction_mode_ == ReductionMode::dpor) { + aid_t issuer_id = state->get_transition_out()->aid_; + stack_t tmp_stack = stack_; + while (not tmp_stack.empty()) { + if (const State* prev_state = tmp_stack.back().get(); + state->get_transition_out()->aid_ == prev_state->get_transition_out()->aid_) { + XBT_DEBUG("Simcall >>%s<< and >>%s<< with same issuer %ld", state->get_transition_out()->to_string().c_str(), + prev_state->get_transition_out()->to_string().c_str(), issuer_id); + tmp_stack.pop_back(); + continue; + } else if (prev_state->get_transition_out()->depends(state->get_transition_out())) { + 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()); + + if (prev_state->is_actor_enabled(issuer_id)) { + if (not prev_state->is_actor_done(issuer_id)) { + prev_state->consider_one(issuer_id); + opened_states_.emplace_back(tmp_stack.back()); + } else + XBT_DEBUG("Actor %ld is already in done set: no need to explore it again", issuer_id); + } else { + XBT_DEBUG("Actor %ld is not enabled: DPOR may be failing. To stay sound, we are marking every enabled " + "transition as todo", + issuer_id); + // If we ended up marking at least a transition, explore it at some point + if (prev_state->consider_all() > 0) + opened_states_.emplace_back(tmp_stack.back()); + } + 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()); + } + tmp_stack.pop_back(); + } + } + + // 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) + 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()); + 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 */ - for (auto const& [aid, _] : next_state->get_actors_list()) { - if (next_state->is_actor_enabled(aid)) { - next_state->mark_todo(aid); - if (reduction_mode_ == ReductionMode::dpor) - break; // With DPOR, we take the first enabled transition - } + 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(); } - mc_model_checker->dot_output("\"%ld\" -> \"%ld\" [%s];\n", state->get_num(), next_state->get_num(), - state->get_transition()->dot_string().c_str()); + 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 + } + } + log_state(); +} - } else - mc_model_checker->dot_output("\"%ld\" -> \"%ld\" [%s];\n", state->get_num(), - visited_state_->original_num == -1 ? visited_state_->num - : visited_state_->original_num, - state->get_transition()->dot_string().c_str()); +std::shared_ptr DFSExplorer::best_opened_state() +{ + int best_prio = 0; // cache the value for the best priority found so far (initialized to silence gcc) + auto best = end(opened_states_); // iterator to the state to explore having the best priority + auto valid = begin(opened_states_); // iterator marking the limit between states still to explore, and already + // explored ones + + // Keep only still non-explored states (aid != -1), and record the one with the best (greater) priority. + for (auto current = begin(opened_states_); current != end(opened_states_); ++current) { + auto [aid, prio] = (*current)->next_transition_guided(); + if (aid == -1) + continue; + if (valid != current) + *valid = std::move(*current); + if (best == end(opened_states_) || prio > best_prio) { + best_prio = prio; + best = valid; + } + ++valid; + } - stack_.push_back(std::move(next_state)); + std::shared_ptr best_state; + if (best < valid) { + // There are non-explored states, and one of them has the best priority. Remove it from opened_states_ before + // returning. + best_state = std::move(*best); + --valid; + if (best != valid) + *best = std::move(*valid); } + opened_states_.erase(valid, end(opened_states_)); - log_state(); + return best_state; } void DFSExplorer::backtrack() { - backtrack_count_++; XBT_VERB("Backtracking from %s", get_record_trace().to_string().c_str()); - on_backtracking_signal(get_remote_app()); - stack_.pop_back(); + XBT_DEBUG("%lu alternatives are yet to be explored:", opened_states_.size()); + on_backtracking_signal(get_remote_app()); get_remote_app().check_deadlock(); - /* Traverse the stack backwards until a state with a non empty interleave set is found, deleting all the states that - * have it empty in the way. For each deleted state, check if the request that has generated it (from its - * predecessor state), depends on any other previous request executed before it. If it does then add it to the - * interleave set of the state that executed that previous request. */ - bool found_backtracking_point = false; - while (not stack_.empty() && not found_backtracking_point) { - std::unique_ptr state = std::move(stack_.back()); - stack_.pop_back(); - if (reduction_mode_ == ReductionMode::dpor) { - aid_t issuer_id = state->get_transition()->aid_; - for (auto i = stack_.rbegin(); i != stack_.rend(); ++i) { - State* prev_state = i->get(); - if (state->get_transition()->aid_ == prev_state->get_transition()->aid_) { - XBT_DEBUG("Simcall >>%s<< and >>%s<< with same issuer %ld", state->get_transition()->to_string().c_str(), - prev_state->get_transition()->to_string().c_str(), issuer_id); - break; - } else if (prev_state->get_transition()->depends(state->get_transition())) { - XBT_VERB("Dependent Transitions:"); - XBT_VERB(" %s (state=%ld)", prev_state->get_transition()->to_string().c_str(), prev_state->get_num()); - XBT_VERB(" %s (state=%ld)", state->get_transition()->to_string().c_str(), state->get_num()); + // Take the point with smallest distance + auto backtracking_point = best_opened_state(); - if (not prev_state->is_done(issuer_id)) - prev_state->mark_todo(issuer_id); - else - XBT_DEBUG("Actor %ld is in done set", issuer_id); - break; - } else { - XBT_VERB("INDEPENDENT Transitions:"); - XBT_VERB(" %s (state=%ld)", prev_state->get_transition()->to_string().c_str(), prev_state->get_num()); - XBT_VERB(" %s (state=%ld)", state->get_transition()->to_string().c_str(), state->get_num()); - } - } - } - - if (state->count_todo() == 0) { // Empty interleaving set - XBT_DEBUG("Delete state %ld at depth %zu", state->get_num(), stack_.size() + 1); - - } else { - XBT_DEBUG("Back-tracking to state %ld at depth %zu", state->get_num(), stack_.size() + 1); - stack_.push_back(std::move(state)); // Put it back on the stack - found_backtracking_point = true; - } + // if no backtracking point, then set the stack_ to empty so we can end the exploration + if (not backtracking_point) { + XBT_DEBUG("No more opened point of exploration, the search will end"); + stack_.clear(); + return; } - if (found_backtracking_point) { - /* If asked to rollback on a state that has a snapshot, restore it */ - State* last_state = stack_.back().get(); - if (const auto* system_state = last_state->get_system_state()) { - system_state->restore(&get_remote_app().get_remote_process()); - on_restore_system_state_signal(last_state, get_remote_app()); - return; - } - - /* if no snapshot, we need to restore the initial state and replay the transitions */ - get_remote_app().restore_initial_state(); - on_restore_initial_state_signal(get_remote_app()); - - /* Traverse the stack from the state at position start and re-execute the transitions */ - for (std::unique_ptr const& state : stack_) { - if (state == stack_.back()) /* If we are arrived on the target state, don't replay the outgoing transition */ - break; - state->get_transition()->replay(); - on_transition_replay_signal(state->get_transition(), get_remote_app()); - /* Update statistics */ - mc_model_checker->inc_visited_states(); - } - } // If no backtracing point, then the stack is empty and the exploration is over + // We found a backtracking point, let's go to it + 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 + + /* if no snapshot, we need to restore the initial state and replay the transitions */ + get_remote_app().restore_initial_state(); + on_restore_initial_state_signal(get_remote_app()); + /* Traverse the stack from the state at position start and re-execute the transitions */ + for (auto& state : backtracking_point->get_recipe()) { + state->replay(get_remote_app()); + on_transition_replay_signal(state, get_remote_app()); + visited_states_count_++; + } + this->restore_stack(backtracking_point); } -DFSExplorer::DFSExplorer(const std::vector& args, bool with_dpor) : Exploration(args) +DFSExplorer::DFSExplorer(const std::vector& args, bool with_dpor, bool need_memory_info) + : Exploration(args, need_memory_info || _sg_mc_termination) { if (with_dpor) reduction_mode_ = ReductionMode::dpor; @@ -279,24 +373,21 @@ DFSExplorer::DFSExplorer(const std::vector& args, bool with_dpor) : Explo } else XBT_INFO("Start a DFS exploration. Reduction is: %s.", to_c_str(reduction_mode_)); - auto initial_state = std::make_unique(get_remote_app()); + auto initial_state = std::make_shared(get_remote_app()); XBT_DEBUG("**************************************************"); + stack_.emplace_back(std::move(initial_state)); + /* Get an enabled actor and insert it in the interleave set of the initial state */ - XBT_DEBUG("Initial state. %d actors to consider", initial_state->get_actor_count()); - for (auto const& [aid, _] : initial_state->get_actors_list()) { - if (initial_state->is_actor_enabled(aid)) { - initial_state->mark_todo(aid); - if (reduction_mode_ == ReductionMode::dpor) { - XBT_DEBUG("Actor %ld is TODO, DPOR is ON so let's go for this one.", aid); - break; - } - XBT_DEBUG("Actor %ld is TODO", aid); - } + XBT_DEBUG("Initial state. %lu actors to consider", stack_.back()->get_actor_count()); + if (reduction_mode_ == ReductionMode::dpor) + stack_.back()->consider_best(); + else { + stack_.back()->consider_all(); } - - stack_.push_back(std::move(initial_state)); + if (stack_.back()->count_todo_multiples() > 1) + opened_states_.emplace_back(stack_.back()); } Exploration* create_dfs_exploration(const std::vector& args, bool with_dpor)