1 /* Copyright (c) 2008-2023. The SimGrid Team. All rights reserved. */
3 /* This program is free software; you can redistribute it and/or modify it
4 * under the terms of the license (GNU LGPL) which comes with this package. */
6 #include "src/mc/api/State.hpp"
7 #include "src/mc/api/strategy/BasicStrategy.hpp"
8 #include "src/mc/api/strategy/WaitStrategy.hpp"
9 #include "src/mc/explo/Exploration.hpp"
10 #include "src/mc/mc_config.hpp"
13 #include <boost/range/algorithm.hpp>
15 XBT_LOG_NEW_DEFAULT_SUBCATEGORY(mc_state, mc, "Logging specific to MC states");
17 namespace simgrid::mc {
19 long State::expended_states_ = 0;
21 State::State(RemoteApp& remote_app) : num_(++expended_states_)
23 XBT_VERB("Creating a guide for the state");
24 if (_sg_mc_strategy == "none")
25 strategy_ = std::make_shared<BasicStrategy>();
26 else if (_sg_mc_strategy == "nb_wait")
27 strategy_ = std::make_shared<WaitStrategy>();
31 remote_app.get_actors_status(strategy_->actors_to_run_);
33 #if SIMGRID_HAVE_STATEFUL_MC
34 /* Stateful model checking */
35 if ((_sg_mc_checkpoint > 0 && (num_ % _sg_mc_checkpoint == 0)) || _sg_mc_termination)
36 system_state_ = std::make_shared<simgrid::mc::Snapshot>(num_, remote_app.get_page_store(),
37 *remote_app.get_remote_process_memory());
41 State::State(RemoteApp& remote_app, std::shared_ptr<State> parent_state)
42 : incoming_transition_(parent_state->get_transition_out()), num_(++expended_states_), parent_state_(parent_state)
44 if (_sg_mc_strategy == "none")
45 strategy_ = std::make_shared<BasicStrategy>();
46 else if (_sg_mc_strategy == "nb_wait")
47 strategy_ = std::make_shared<WaitStrategy>();
50 *strategy_ = *(parent_state->strategy_);
52 remote_app.get_actors_status(strategy_->actors_to_run_);
54 #if SIMGRID_HAVE_STATEFUL_MC /* Stateful model checking */
55 if ((_sg_mc_checkpoint > 0 && (num_ % _sg_mc_checkpoint == 0)) || _sg_mc_termination)
56 system_state_ = std::make_shared<simgrid::mc::Snapshot>(num_, remote_app.get_page_store(),
57 *remote_app.get_remote_process_memory());
60 /* If we want sleep set reduction, copy the sleep set and eventually removes things from it */
61 if (_sg_mc_sleep_set) {
62 /* For each actor in the previous sleep set, keep it if it is not dependent with current transition.
63 * And if we kept it and the actor is enabled in this state, mark the actor as already done, so that
64 * it is not explored*/
65 for (auto& [aid, transition] : parent_state_->get_sleep_set()) {
66 if (not incoming_transition_->depends(transition.get())) {
67 sleep_set_.try_emplace(aid, transition);
68 if (strategy_->actors_to_run_.count(aid) != 0) {
69 XBT_DEBUG("Actor %ld will not be explored, for it is in the sleep set", aid);
70 strategy_->actors_to_run_.at(aid).mark_done();
73 XBT_DEBUG("Transition >>%s<< removed from the sleep set because it was dependent with incoming >>%s<<",
74 transition->to_string().c_str(), incoming_transition_->to_string().c_str());
79 std::size_t State::count_todo() const
81 return boost::range::count_if(this->strategy_->actors_to_run_, [](auto& pair) { return pair.second.is_todo(); });
84 std::size_t State::count_todo_multiples() const
87 for (auto const& [_, actor] : strategy_->actors_to_run_)
89 count += actor.get_times_not_considered();
94 aid_t State::next_transition() const
96 XBT_DEBUG("Search for an actor to run. %zu actors to consider", strategy_->actors_to_run_.size());
97 for (auto const& [aid, actor] : strategy_->actors_to_run_) {
98 /* Only consider actors (1) marked as interleaving by the checker and (2) currently enabled in the application */
99 if (not actor.is_todo() || not actor.is_enabled() || actor.is_done()) {
100 if (not actor.is_todo())
101 XBT_DEBUG("Can't run actor %ld because it is not todo", aid);
103 if (not actor.is_enabled())
104 XBT_DEBUG("Can't run actor %ld because it is not enabled", aid);
107 XBT_DEBUG("Can't run actor %ld because it has already been done", aid);
117 std::pair<aid_t, int> State::next_transition_guided() const
119 return strategy_->next_transition();
122 aid_t State::next_odpor_transition() const
124 return wakeup_tree_.get_min_single_process_actor().value_or(-1);
127 // This should be done in GuidedState, or at least interact with it
128 std::shared_ptr<Transition> State::execute_next(aid_t next, RemoteApp& app)
130 // First, warn the guide, so it knows how to build a proper child state
131 strategy_->execute_next(next, app);
133 // This actor is ready to be executed. Execution involves three phases:
135 // 1. Identify the appropriate ActorState to prepare for execution
136 // when simcall_handle will be called on it
137 auto& actor_state = strategy_->actors_to_run_.at(next);
138 const unsigned times_considered = actor_state.do_consider();
139 const auto* expected_executed_transition = actor_state.get_transition(times_considered).get();
140 xbt_assert(expected_executed_transition != nullptr,
141 "Expected a transition with %u times considered to be noted in actor %ld", times_considered, next);
143 XBT_DEBUG("Let's run actor %ld (times_considered = %u)", next, times_considered);
145 // 2. Execute the actor according to the preparation above
146 Transition::executed_transitions_++;
147 auto* just_executed = app.handle_simcall(next, times_considered, true);
148 xbt_assert(just_executed->type_ == expected_executed_transition->type_,
149 "The transition that was just executed by actor %ld, viz:\n"
151 "is not what was purportedly scheduled to execute, which was:\n"
153 next, just_executed->to_string().c_str(), expected_executed_transition->to_string().c_str());
155 // 3. Update the state with the newest information. This means recording
157 // 1. what action was last taken from this state (viz. `executed_transition`)
158 // 2. what action actor `next` was able to take given `times_considered`
159 // The latter update is important as *more* information is potentially available
160 // about a transition AFTER it has executed.
161 outgoing_transition_ = std::shared_ptr<Transition>(just_executed);
163 actor_state.set_transition(outgoing_transition_, times_considered);
164 app.wait_for_requests();
166 return outgoing_transition_;
169 std::unordered_set<aid_t> State::get_backtrack_set() const
171 std::unordered_set<aid_t> actors;
172 for (const auto& [aid, state] : get_actors_list()) {
173 if (state.is_todo() or state.is_done()) {
180 std::unordered_set<aid_t> State::get_sleeping_actors() const
182 std::unordered_set<aid_t> actors;
183 for (const auto& [aid, _] : get_sleep_set()) {
189 std::unordered_set<aid_t> State::get_enabled_actors() const
191 std::unordered_set<aid_t> actors;
192 for (const auto& [aid, state] : get_actors_list()) {
193 if (state.is_enabled()) {
200 void State::seed_wakeup_tree_if_needed(const odpor::Execution& prior)
202 // TODO: It would be better not to have such a flag.
203 if (has_initialized_wakeup_tree) {
206 // TODO: Note that the next action taken by the actor may be updated
207 // after it executes. But we will have already inserted it into the
208 // tree and decided upon "happens-before" at that point for different
210 if (wakeup_tree_.empty()) {
211 // Find an enabled transition to pick
212 for (const auto& [_, actor] : get_actors_list()) {
213 if (actor.is_enabled()) {
214 // For each variant of the transition, we want
215 // to insert the action into the tree. This ensures
216 // that all variants are searched
217 for (unsigned times = 0; times < actor.get_max_considered(); ++times) {
218 wakeup_tree_.insert(prior, odpor::PartialExecution{actor.get_transition(times)});
220 break; // Only one actor gets inserted (see pseudocode)
224 has_initialized_wakeup_tree = true;
227 void State::sprout_tree_from_parent_state()
229 xbt_assert(parent_state_ != nullptr, "Attempting to construct a wakeup tree for the root state "
230 "(or what appears to be, rather for state without a parent defined)");
231 const auto min_process_node = parent_state_->wakeup_tree_.get_min_single_process_node();
232 xbt_assert(min_process_node.has_value(), "Attempting to construct a subtree for a substate from a "
233 "parent with an empty wakeup tree. This indicates either that ODPOR "
234 "actor selection in State.cpp is incorrect, or that the code "
235 "deciding when to make subtrees in ODPOR is incorrect");
236 xbt_assert((get_transition_in()->aid_ == min_process_node.value()->get_actor()) &&
237 (get_transition_in()->type_ == min_process_node.value()->get_action()->type_),
238 "We tried to make a subtree from a parent state who claimed to have executed `%s` "
239 "but whose wakeup tree indicates it should have executed `%s`. This indicates "
240 "that exploration is not following ODPOR. Are you sure you're choosing actors "
241 "to schedule from the wakeup tree?",
242 get_transition_in()->to_string(false).c_str(),
243 min_process_node.value()->get_action()->to_string(false).c_str());
244 this->wakeup_tree_ = odpor::WakeupTree::make_subtree_rooted_at(min_process_node.value());
247 void State::remove_subtree_using_current_out_transition()
249 if (auto out_transition = get_transition_out(); out_transition != nullptr) {
250 if (const auto min_process_node = wakeup_tree_.get_min_single_process_node(); min_process_node.has_value()) {
251 xbt_assert((out_transition->aid_ == min_process_node.value()->get_actor()) &&
252 (out_transition->type_ == min_process_node.value()->get_action()->type_),
253 "We tried to make a subtree from a parent state who claimed to have executed `%s` "
254 "but whose wakeup tree indicates it should have executed `%s`. This indicates "
255 "that exploration is not following ODPOR. Are you sure you're choosing actors "
256 "to schedule from the wakeup tree?",
257 out_transition->to_string(false).c_str(),
258 min_process_node.value()->get_action()->to_string(false).c_str());
261 wakeup_tree_.remove_min_single_process_subtree();
264 odpor::WakeupTree::InsertionResult State::insert_into_wakeup_tree(const odpor::PartialExecution& pe,
265 const odpor::Execution& E)
267 return this->wakeup_tree_.insert(E, pe);
270 void State::do_odpor_unwind()
272 if (auto out_transition = get_transition_out(); out_transition != nullptr) {
273 remove_subtree_using_current_out_transition();
275 // Only when we've exhausted all variants of the transition which
276 // can be chosen from this state do we finally add the actor to the
277 // sleep set. This ensures that the current logic handling sleep sets
278 // works with ODPOR in the way we intend it to work. There is not a
279 // good way to perform transition equality in SimGrid; instead, we
280 // effectively simply check for the presence of an actor in the sleep set.
281 if (!get_actors_list().at(out_transition->aid_).has_more_to_consider())
282 add_sleep_set(std::move(out_transition));
286 } // namespace simgrid::mc