From a6d5fdeb22df5f5b1ca02a3dad8ba6094202a4f3 Mon Sep 17 00:00:00 2001 From: mlaurent Date: Thu, 23 Mar 2023 09:50:33 +0100 Subject: [PATCH] try to fix stack handling --- src/mc/explo/DFSExplorer.cpp | 136 ++++++++++++++++++++--------------- src/mc/explo/DFSExplorer.hpp | 9 ++- 2 files changed, 85 insertions(+), 60 deletions(-) diff --git a/src/mc/explo/DFSExplorer.cpp b/src/mc/explo/DFSExplorer.cpp index c58d581120..792383ecee 100644 --- a/src/mc/explo/DFSExplorer.cpp +++ b/src/mc/explo/DFSExplorer.cpp @@ -133,8 +133,8 @@ void DFSExplorer::run() auto [next, _] = state->next_transition_guided(); if (next < 0) { // If there is no more transition in the current state, backtrack. - XBT_DEBUG("There remains %lu actors, but none to interleave (depth %zu).", state->get_actor_count(), - stack_.size() + 1); + XBT_VERB("There remains %lu actors, but none to interleave (depth %zu).", state->get_actor_count(), + stack_.size() + 1); if (state->get_actor_count() == 0) { get_remote_app().finalize_app(); @@ -162,9 +162,8 @@ void DFSExplorer::run() state->get_transition()->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) */ - std::unique_ptr next_state; - - next_state = std::make_unique(get_remote_app(), state); + std::shared_ptr next_state; + next_state = std::make_shared(get_remote_app(), state); on_state_creation_signal(next_state.get(), get_remote_app()); /* Sleep set procedure: @@ -180,12 +179,14 @@ void DFSExplorer::run() * 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()->aid_; - for (auto i = stack_.rbegin(); i != stack_.rend(); ++i) { - State* prev_state = i->get(); + aid_t issuer_id = state->get_transition()->aid_; + stack_t tmp_stack = std::list(stack_); + while (not tmp_stack.empty()) { + State* prev_state = tmp_stack.back().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); + tmp_stack.pop_back(); continue; } else if (prev_state->get_transition()->depends(state->get_transition())) { XBT_VERB("Dependent Transitions:"); @@ -193,15 +194,17 @@ void DFSExplorer::run() XBT_VERB(" %s (state=%ld)", state->get_transition()->to_string().c_str(), state->get_num()); if (prev_state->is_actor_enabled(issuer_id)) { - if (not prev_state->is_actor_done(issuer_id)) + if (not prev_state->is_actor_done(issuer_id)) { prev_state->consider_one(issuer_id); - else + opened_states.emplace_back(tmp_stack); + } 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); prev_state->consider_all(); + opened_states.emplace_back(tmp_stack); } break; } else { @@ -209,6 +212,7 @@ void DFSExplorer::run() 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()); } + tmp_stack.pop_back(); } } @@ -219,22 +223,23 @@ void DFSExplorer::run() if (_sg_mc_max_visited_states > 0) visited_state_ = visited_states_.addVisitedState(next_state->get_num(), next_state.get(), get_remote_app()); + stack_.push_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) - next_state->consider_best(); // Take only one transition if DPOR: others may be considered later if required - else - next_state->consider_all(); - - dot_output("\"%ld\" -> \"%ld\" [%s];\n", state->get_num(), next_state->get_num(), + stack_.back()->consider_best(); // Take only one transition if DPOR: others may be considered later if required + else { + stack_.back()->consider_all(); + opened_states.emplace_back(stack_); + } + dot_output("\"%ld\" -> \"%ld\" [%s];\n", state->get_num(), stack_.back()->get_num(), state->get_transition()->dot_string().c_str()); } 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()->dot_string().c_str()); - - stack_.push_back(std::move(next_state)); } log_state(); @@ -247,53 +252,64 @@ void DFSExplorer::backtrack() 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) { + stack_ = std::list>(); + 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(); - /* 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. */ - bool found_backtracking_point = false; - while (not stack_.empty() && not found_backtracking_point) { - std::unique_ptr state = std::move(stack_.back()); - - stack_.pop_back(); + stack_t backtrack; + double min_dist = std::numeric_limits::infinity(); + aid_t min_aid = -1; + for (auto& stack : opened_states) { + auto [aid, dist] = stack.back()->next_transition_guided(); + if (aid == -1) + continue; + if (dist < min_dist) { + min_dist = dist; + min_aid = aid; + backtrack = stack; + } + } - if (state->count_todo() == 0) { // Empty interleaving set: exploration at this level is over - XBT_DEBUG("Delete state %ld at depth %zu", state->get_num(), stack_.size() + 1); + if (min_aid == -1) { + stack_ = std::list>(); + return; + } - } else { - XBT_DEBUG("Back-tracking to state %ld at depth %zu: %lu transitions left to be explored", state->get_num(), - stack_.size() + 1, state->count_todo()); - stack_.push_back( - std::move(state)); // Put it back on the stack so we can explore the next transition of the interleave - found_backtracking_point = true; - } + if (backtrack.back()->count_todo() <= 1) + opened_states.pop_back(); + XBT_VERB("%lu todo actors in last states of the next backtracking point %s (remaining %lu opened stacks)", + backtrack.back()->count_todo(), backtrack.back()->get_transition()->to_string().c_str(), + opened_states.size()); + + /* If asked to rollback on a state that has a snapshot, restore it */ + State* last_state = backtrack.back().get(); + if (const auto* system_state = last_state->get_system_state()) { + system_state->restore(get_remote_app().get_remote_process_memory()); + on_restore_system_state_signal(last_state, get_remote_app()); + 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_memory()); - 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()); - /* 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(get_remote_app()); - on_transition_replay_signal(state->get_transition(), get_remote_app()); - visited_states_count_++; - } - } // If no backtracing point, then the stack is empty and the exploration is over + /* Traverse the stack from the state at position start and re-execute the transitions */ + for (std::shared_ptr const& state : backtrack) { + if (state == backtrack.back()) /* If we are arrived on the target state, don't replay the outgoing transition */ + break; + state->get_transition()->replay(get_remote_app()); + on_transition_replay_signal(state->get_transition(), get_remote_app()); + visited_states_count_++; + } + stack_ = backtrack; + XBT_VERB(">> Backtracked to %s", get_record_trace().to_string().c_str()); } DFSExplorer::DFSExplorer(const std::vector& args, bool with_dpor) : Exploration(args) @@ -317,14 +333,16 @@ DFSExplorer::DFSExplorer(const std::vector& args, bool with_dpor) : Explo XBT_DEBUG("**************************************************"); + stack_.push_back(std::move(initial_state)); + /* Get an enabled actor and insert it in the interleave set of the initial state */ XBT_DEBUG("Initial state. %lu actors to consider", initial_state->get_actor_count()); if (reduction_mode_ == ReductionMode::dpor) - initial_state->consider_best(); - else - initial_state->consider_all(); - - stack_.push_back(std::move(initial_state)); + stack_.back()->consider_best(); + else { + stack_.back()->consider_all(); + opened_states.emplace_back(stack_); + } } Exploration* create_dfs_exploration(const std::vector& args, bool with_dpor) diff --git a/src/mc/explo/DFSExplorer.hpp b/src/mc/explo/DFSExplorer.hpp index 8d63ca4e23..e20e267614 100644 --- a/src/mc/explo/DFSExplorer.hpp +++ b/src/mc/explo/DFSExplorer.hpp @@ -16,7 +16,10 @@ namespace simgrid::mc { +typedef std::list> stack_t; + class XBT_PRIVATE DFSExplorer : public Exploration { + XBT_DECLARE_ENUM_CLASS(ReductionMode, none, dpor); ReductionMode reduction_mode_; @@ -86,9 +89,13 @@ private: void backtrack(); /** Stack representing the position in the exploration graph */ - std::list> stack_; + stack_t stack_; VisitedStates visited_states_; std::unique_ptr visited_state_; + + /** Opened states are states that still contains todo actors. + * When backtracking, we pick a state from it*/ + std::vector opened_states; }; } // namespace simgrid::mc -- 2.20.1