src/mc/checker/CommunicationDeterminismChecker.cpp

   1 /* Copyright (c) 2008-2022. The SimGrid Team. All rights reserved.          */
   2
   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. */
   5
   6 #include "src/mc/checker/CommunicationDeterminismChecker.hpp"
   7 #include "src/kernel/activity/MailboxImpl.hpp"
   8 #include "src/mc/Session.hpp"
   9 #include "src/mc/api/TransitionComm.hpp"
  10 #include "src/mc/mc_config.hpp"
  11 #include "src/mc/mc_exit.hpp"
  12 #include "src/mc/mc_private.hpp"
  13
  14 #include <cstdint>
  15
  16 using api = simgrid::mc::Api;
  17
  18 XBT_LOG_NEW_DEFAULT_SUBCATEGORY(mc_comm_determinism, mc, "Logging specific to MC communication determinism detection");
  19
  20 namespace simgrid {
  21 namespace mc {
  22
  23 enum class CallType { NONE, SEND, RECV, WAIT, WAITANY };
  24 enum class CommPatternDifference { NONE, TYPE, MBOX, TAG, SRC_PROC, DST_PROC, DATA_SIZE };
  25 enum class PatternCommunicationType {
  26   none    = 0,
  27   send    = 1,
  28   receive = 2,
  29 };
  30
  31 class PatternCommunication {
  32 public:
  33   int num = 0;
  34   uintptr_t comm_addr           = 0;
  35   PatternCommunicationType type = PatternCommunicationType::send;
  36   unsigned long src_proc        = 0;
  37   unsigned long dst_proc        = 0;
  38   unsigned mbox                 = 0;
  39   unsigned size                 = 0;
  40   int tag   = 0;
  41   int index = 0;
  42
  43   PatternCommunication dup() const
  44   {
  45     simgrid::mc::PatternCommunication res;
  46     // num?
  47     res.comm_addr = this->comm_addr;
  48     res.type      = this->type;
  49     // src_proc?
  50     // dst_proc?
  51     res.dst_proc = this->dst_proc;
  52     res.mbox     = this->mbox;
  53     // tag?
  54     res.index = this->index;
  55     return res;
  56   }
  57 };
  58
  59 struct PatternCommunicationList {
  60   unsigned int index_comm = 0;
  61   std::vector<std::unique_ptr<simgrid::mc::PatternCommunication>> list;
  62 };
  63
  64 /********** Checker extension **********/
  65
  66 struct CommDetExtension {
  67   static simgrid::xbt::Extension<simgrid::mc::Checker, CommDetExtension> EXTENSION_ID;
  68
  69   CommDetExtension()
  70   {
  71     const unsigned long maxpid = api::get().get_maxpid();
  72
  73     initial_communications_pattern.resize(maxpid);
  74     incomplete_communications_pattern.resize(maxpid);
  75   }
  76
  77   std::vector<simgrid::mc::PatternCommunicationList> initial_communications_pattern;
  78   std::vector<std::vector<simgrid::mc::PatternCommunication*>> incomplete_communications_pattern;
  79
  80   bool initial_communications_pattern_done = false;
  81   bool recv_deterministic                  = true;
  82   bool send_deterministic                  = true;
  83   std::string send_diff;
  84   std::string recv_diff;
  85
  86   void restore_communications_pattern(const simgrid::mc::State* state);
  87   void deterministic_comm_pattern(aid_t process, const PatternCommunication* comm, bool backtracking);
  88   void get_comm_pattern(const Transition* transition, bool backtracking);
  89   void complete_comm_pattern(const CommWaitTransition* transition, bool backtracking);
  90   void handle_comm_pattern(const Transition* transition, bool backtracking);
  91 };
  92 simgrid::xbt::Extension<simgrid::mc::Checker, CommDetExtension> CommDetExtension::EXTENSION_ID;
  93 /********** State Extension ***********/
  94
  95 class StateCommDet {
  96   CommDetExtension* checker_;
  97
  98 public:
  99   std::vector<std::vector<simgrid::mc::PatternCommunication>> incomplete_comm_pattern_;
 100   std::vector<unsigned> communication_indices_;
 101
 102   static simgrid::xbt::Extension<simgrid::mc::State, StateCommDet> EXTENSION_ID;
 103   explicit StateCommDet(CommDetExtension* checker) : checker_(checker)
 104   {
 105     copy_incomplete_comm_pattern();
 106     copy_index_comm_pattern();
 107   }
 108
 109   void copy_incomplete_comm_pattern()
 110   {
 111     incomplete_comm_pattern_.clear();
 112     const unsigned long maxpid = api::get().get_maxpid();
 113     for (unsigned long i = 0; i < maxpid; i++) {
 114       std::vector<simgrid::mc::PatternCommunication> res;
 115       for (auto const& comm : checker_->incomplete_communications_pattern[i])
 116         res.push_back(comm->dup());
 117       incomplete_comm_pattern_.push_back(std::move(res));
 118     }
 119   }
 120
 121   void copy_index_comm_pattern()
 122   {
 123     communication_indices_.clear();
 124     for (auto const& list_process_comm : checker_->initial_communications_pattern)
 125       this->communication_indices_.push_back(list_process_comm.index_comm);
 126   }
 127 };
 128 simgrid::xbt::Extension<simgrid::mc::State, StateCommDet> StateCommDet::EXTENSION_ID;
 129
 130 static simgrid::mc::CommPatternDifference compare_comm_pattern(const simgrid::mc::PatternCommunication* comm1,
 131                                                                const simgrid::mc::PatternCommunication* comm2)
 132 {
 133   using simgrid::mc::CommPatternDifference;
 134   if (comm1->type != comm2->type)
 135     return CommPatternDifference::TYPE;
 136   if (comm1->mbox != comm2->mbox)
 137     return CommPatternDifference::MBOX;
 138   if (comm1->src_proc != comm2->src_proc)
 139     return CommPatternDifference::SRC_PROC;
 140   if (comm1->dst_proc != comm2->dst_proc)
 141     return CommPatternDifference::DST_PROC;
 142   if (comm1->tag != comm2->tag)
 143     return CommPatternDifference::TAG;
 144   if (comm1->size != comm2->size)
 145     return CommPatternDifference::DATA_SIZE;
 146   return CommPatternDifference::NONE;
 147 }
 148
 149 void CommDetExtension::restore_communications_pattern(const simgrid::mc::State* state)
 150 {
 151   for (size_t i = 0; i < initial_communications_pattern.size(); i++)
 152     initial_communications_pattern[i].index_comm =
 153         state->extension<simgrid::mc::StateCommDet>()->communication_indices_[i];
 154
 155   const unsigned long maxpid = api::get().get_maxpid();
 156   for (unsigned long i = 0; i < maxpid; i++) {
 157     incomplete_communications_pattern[i].clear();
 158     for (simgrid::mc::PatternCommunication const& comm :
 159          state->extension<simgrid::mc::StateCommDet>()->incomplete_comm_pattern_[i])
 160       incomplete_communications_pattern[i].push_back(new simgrid::mc::PatternCommunication(comm.dup()));
 161   }
 162 }
 163
 164 static std::string print_determinism_result(simgrid::mc::CommPatternDifference diff, aid_t process,
 165                                             const simgrid::mc::PatternCommunication* comm, unsigned int cursor)
 166 {
 167   std::string type;
 168   std::string res;
 169
 170   if (comm->type == simgrid::mc::PatternCommunicationType::send)
 171     type = xbt::string_printf("The send communications pattern of the process %ld is different!", process - 1);
 172   else
 173     type = xbt::string_printf("The recv communications pattern of the process %ld is different!", process - 1);
 174
 175   using simgrid::mc::CommPatternDifference;
 176   switch (diff) {
 177     case CommPatternDifference::TYPE:
 178       res = xbt::string_printf("%s Different type for communication #%u", type.c_str(), cursor);
 179       break;
 180     case CommPatternDifference::MBOX:
 181       res = xbt::string_printf("%s Different mailbox for communication #%u", type.c_str(), cursor);
 182       break;
 183     case CommPatternDifference::TAG:
 184       res = xbt::string_printf("%s Different tag for communication #%u", type.c_str(), cursor);
 185       break;
 186     case CommPatternDifference::SRC_PROC:
 187       res = xbt::string_printf("%s Different source for communication #%u", type.c_str(), cursor);
 188       break;
 189     case CommPatternDifference::DST_PROC:
 190       res = xbt::string_printf("%s Different destination for communication #%u", type.c_str(), cursor);
 191       break;
 192     case CommPatternDifference::DATA_SIZE:
 193       res = xbt::string_printf("%s Different data size for communication #%u", type.c_str(), cursor);
 194       break;
 195     default:
 196       res = "";
 197       break;
 198   }
 199
 200   return res;
 201 }
 202
 203 void CommDetExtension::deterministic_comm_pattern(aid_t actor, const PatternCommunication* comm, bool backtracking)
 204 {
 205   if (not backtracking) {
 206     PatternCommunicationList& list = initial_communications_pattern[actor];
 207     CommPatternDifference diff     = compare_comm_pattern(list.list[list.index_comm].get(), comm);
 208
 209     if (diff != CommPatternDifference::NONE) {
 210       if (comm->type == PatternCommunicationType::send) {
 211         send_deterministic = false;
 212         send_diff          = print_determinism_result(diff, actor, comm, list.index_comm + 1);
 213       } else {
 214         recv_deterministic = false;
 215         recv_diff          = print_determinism_result(diff, actor, comm, list.index_comm + 1);
 216       }
 217       if (_sg_mc_send_determinism && not send_deterministic) {
 218         XBT_INFO("*********************************************************");
 219         XBT_INFO("***** Non-send-deterministic communications pattern *****");
 220         XBT_INFO("*********************************************************");
 221         XBT_INFO("%s", send_diff.c_str());
 222         api::get().log_state();
 223         api::get().mc_exit(SIMGRID_MC_EXIT_NON_DETERMINISM);
 224       } else if (_sg_mc_comms_determinism && (not send_deterministic && not recv_deterministic)) {
 225         XBT_INFO("****************************************************");
 226         XBT_INFO("***** Non-deterministic communications pattern *****");
 227         XBT_INFO("****************************************************");
 228         if (not send_diff.empty())
 229           XBT_INFO("%s", send_diff.c_str());
 230         if (not recv_diff.empty())
 231           XBT_INFO("%s", recv_diff.c_str());
 232         api::get().log_state();
 233         api::get().mc_exit(SIMGRID_MC_EXIT_NON_DETERMINISM);
 234       }
 235     }
 236   }
 237 }
 238
 239 /********** Non Static functions ***********/
 240
 241 void CommDetExtension::get_comm_pattern(const Transition* transition, bool backtracking)
 242 {
 243   const mc::PatternCommunicationList& initial_pattern          = initial_communications_pattern[transition->aid_];
 244   const std::vector<PatternCommunication*>& incomplete_pattern = incomplete_communications_pattern[transition->aid_];
 245
 246   auto pattern   = std::make_unique<PatternCommunication>();
 247   pattern->index = initial_pattern.index_comm + incomplete_pattern.size();
 248
 249   if (transition->type_ == Transition::Type::COMM_SEND) {
 250     auto* send = dynamic_cast<const CommSendTransition*>(transition);
 251     /* Create comm pattern */
 252     pattern->type      = PatternCommunicationType::send;
 253     pattern->comm_addr = send->get_comm();
 254     pattern->mbox      = send->get_mailbox();
 255     pattern->src_proc  = send->aid_;
 256
 257 #if HAVE_SMPI
 258     pattern->tag = 0; // FIXME: replace it by the real tag from the observer
 259 #endif
 260
 261 #if HAVE_SMPI
 262     // auto send_detached = api::get().check_send_request_detached(request);
 263     if (false) { // send_detached) {
 264       if (initial_communications_pattern_done) {
 265         /* Evaluate comm determinism */
 266         deterministic_comm_pattern(pattern->src_proc, pattern.get(), backtracking);
 267         initial_communications_pattern[pattern->src_proc].index_comm++;
 268       } else {
 269         /* Store comm pattern */
 270         initial_communications_pattern[pattern->src_proc].list.push_back(std::move(pattern));
 271       }
 272       return;
 273     }
 274 #endif
 275   } else if (transition->type_ == Transition::Type::COMM_RECV) {
 276     auto* recv = static_cast<const CommRecvTransition*>(transition);
 277
 278     pattern->type = PatternCommunicationType::receive;
 279     pattern->comm_addr = recv->get_comm();
 280
 281 #if HAVE_SMPI
 282     pattern->tag = 0; // FIXME: replace it by the real tag from the observer
 283 #endif
 284     pattern->mbox     = recv->get_mailbox();
 285     pattern->dst_proc = recv->aid_;
 286   }
 287
 288   XBT_DEBUG("Insert incomplete comm pattern %p type:%d for process %ld (comm: %" PRIxPTR ")", pattern.get(),
 289             (int)pattern->type, transition->aid_, pattern->comm_addr);
 290   incomplete_communications_pattern[transition->aid_].push_back(pattern.release());
 291 }
 292
 293 void CommDetExtension::complete_comm_pattern(const CommWaitTransition* transition, bool backtracking)
 294 {
 295   /* Complete comm pattern */
 296   std::vector<PatternCommunication*>& incomplete_pattern = incomplete_communications_pattern[transition->aid_];
 297   uintptr_t comm_addr                                    = transition->get_comm();
 298   auto current_comm_pattern =
 299       std::find_if(begin(incomplete_pattern), end(incomplete_pattern),
 300                    [&comm_addr](const PatternCommunication* comm) { return (comm->comm_addr == comm_addr); });
 301   xbt_assert(current_comm_pattern != std::end(incomplete_pattern), "Corresponding communication not found!");
 302   std::unique_ptr<PatternCommunication> comm_pattern(*current_comm_pattern);
 303
 304   comm_pattern->src_proc = transition->get_sender();
 305   comm_pattern->dst_proc = transition->get_receiver();
 306
 307   XBT_DEBUG("Remove incomplete comm pattern for actor %ld at cursor %zd", transition->aid_,
 308             std::distance(begin(incomplete_pattern), current_comm_pattern));
 309   incomplete_pattern.erase(current_comm_pattern);
 310
 311   if (initial_communications_pattern_done) {
 312     /* Evaluate comm determinism */
 313     deterministic_comm_pattern(transition->aid_, comm_pattern.get(), backtracking);
 314     initial_communications_pattern[transition->aid_].index_comm++;
 315   } else {
 316     /* Store comm pattern */
 317     initial_communications_pattern[transition->aid_].list.push_back(std::move(comm_pattern));
 318   }
 319 }
 320
 321 CommunicationDeterminismChecker::CommunicationDeterminismChecker(Session* session) : Checker(session)
 322 {
 323   CommDetExtension::EXTENSION_ID = simgrid::mc::Checker::extension_create<CommDetExtension>();
 324   StateCommDet::EXTENSION_ID = simgrid::mc::State::extension_create<StateCommDet>();
 325 }
 326
 327 CommunicationDeterminismChecker::~CommunicationDeterminismChecker() = default;
 328
 329 RecordTrace CommunicationDeterminismChecker::get_record_trace() // override
 330 {
 331   RecordTrace res;
 332   for (auto const& state : stack_)
 333     res.push_back(state->get_transition());
 334   return res;
 335 }
 336
 337 std::vector<std::string> CommunicationDeterminismChecker::get_textual_trace() // override
 338 {
 339   std::vector<std::string> trace;
 340   for (auto const& state : stack_)
 341     trace.push_back(state->get_transition()->to_string());
 342   return trace;
 343 }
 344
 345 void CommunicationDeterminismChecker::log_state() // override
 346 {
 347   if (_sg_mc_comms_determinism) {
 348     if (extension<CommDetExtension>()->send_deterministic && not extension<CommDetExtension>()->recv_deterministic) {
 349       XBT_INFO("*******************************************************");
 350       XBT_INFO("**** Only-send-deterministic communication pattern ****");
 351       XBT_INFO("*******************************************************");
 352       XBT_INFO("%s", extension<CommDetExtension>()->recv_diff.c_str());
 353     }
 354     if (not extension<CommDetExtension>()->send_deterministic && extension<CommDetExtension>()->recv_deterministic) {
 355       XBT_INFO("*******************************************************");
 356       XBT_INFO("**** Only-recv-deterministic communication pattern ****");
 357       XBT_INFO("*******************************************************");
 358       XBT_INFO("%s", extension<CommDetExtension>()->send_diff.c_str());
 359     }
 360   }
 361   XBT_INFO("Expanded states = %ld", State::get_expanded_states());
 362   XBT_INFO("Visited states = %lu", api::get().mc_get_visited_states());
 363   XBT_INFO("Executed transitions = %lu", Transition::get_executed_transitions());
 364   XBT_INFO("Send-deterministic : %s", extension<CommDetExtension>()->send_deterministic ? "Yes" : "No");
 365   if (_sg_mc_comms_determinism)
 366     XBT_INFO("Recv-deterministic : %s", extension<CommDetExtension>()->recv_deterministic ? "Yes" : "No");
 367 }
 368
 369 void CommunicationDeterminismChecker::prepare()
 370 {
 371   auto initial_state = std::make_unique<State>();
 372   extension_set(new CommDetExtension());
 373   initial_state->extension_set(new StateCommDet(extension<CommDetExtension>()));
 374
 375   XBT_DEBUG("********* Start communication determinism verification *********");
 376
 377   /* Add all enabled actors to the interleave set of the initial state */
 378   for (auto& act : api::get().get_actors()) {
 379     auto actor = act.copy.get_buffer();
 380     if (get_session().actor_is_enabled(actor->get_pid()))
 381       initial_state->mark_todo(actor->get_pid());
 382   }
 383
 384   stack_.push_back(std::move(initial_state));
 385 }
 386
 387 void CommunicationDeterminismChecker::restoreState()
 388 {
 389   auto extension = this->extension<CommDetExtension>();
 390
 391   /* If asked to rollback on a state that has a snapshot, restore it */
 392   State* last_state = stack_.back().get();
 393   if (last_state->system_state_) {
 394     api::get().restore_state(last_state->system_state_);
 395     extension->restore_communications_pattern(last_state);
 396     return;
 397   }
 398
 399   /* if no snapshot, we need to restore the initial state and replay the transitions */
 400   get_session().restore_initial_state();
 401
 402   const unsigned long maxpid = api::get().get_maxpid();
 403   assert(maxpid == extension->incomplete_communications_pattern.size());
 404   assert(maxpid == extension->initial_communications_pattern.size());
 405   for (unsigned long j = 0; j < maxpid; j++) {
 406     extension->incomplete_communications_pattern[j].clear();
 407     extension->initial_communications_pattern[j].index_comm = 0;
 408   }
 409
 410   /* Traverse the stack from the state at position start and re-execute the transitions */
 411   for (std::unique_ptr<simgrid::mc::State> const& state : stack_) {
 412     if (state == stack_.back())
 413       break;
 414
 415     auto* transition = state->get_transition();
 416     transition->replay();
 417     extension->handle_comm_pattern(transition, true);
 418
 419     /* Update statistics */
 420     api::get().mc_inc_visited_states();
 421   }
 422 }
 423
 424 void CommDetExtension::handle_comm_pattern(const Transition* transition, bool backtracking)
 425 {
 426   if (not _sg_mc_comms_determinism && not _sg_mc_send_determinism)
 427     return;
 428
 429   switch (transition->type_) {
 430     case Transition::Type::COMM_SEND:
 431       get_comm_pattern(transition, backtracking);
 432       break;
 433     case Transition::Type::COMM_RECV:
 434       get_comm_pattern(transition, backtracking);
 435       break;
 436     case Transition::Type::COMM_WAIT: {
 437       complete_comm_pattern(static_cast<const CommWaitTransition*>(transition), backtracking);
 438       break;
 439     }
 440     case Transition::Type::WAITANY: {
 441       auto const* t    = static_cast<const WaitAnyTransition*>(transition)->get_current_transition();
 442       auto const* wait = dynamic_cast<const CommWaitTransition*>(t);
 443       if (wait != nullptr) // Ignore wait on non-comm
 444         complete_comm_pattern(wait, backtracking);
 445     } break;
 446     default: /* Ignore unhandled transition types */
 447       break;
 448   }
 449 }
 450
 451 void CommunicationDeterminismChecker::real_run()
 452 {
 453   auto extension = this->extension<CommDetExtension>();
 454
 455   std::unique_ptr<VisitedState> visited_state = nullptr;
 456   const unsigned long maxpid                  = api::get().get_maxpid();
 457
 458   while (not stack_.empty()) {
 459     /* Get current state */
 460     State* cur_state = stack_.back().get();
 461
 462     XBT_DEBUG("**************************************************");
 463     XBT_DEBUG("Exploration depth = %zu (state = %ld, interleaved processes = %zu)", stack_.size(), cur_state->num_,
 464               cur_state->count_todo());
 465
 466     /* Update statistics */
 467     api::get().mc_inc_visited_states();
 468
 469     int next_transition = -1;
 470     if (stack_.size() <= (std::size_t)_sg_mc_max_depth)
 471       next_transition = cur_state->next_transition();
 472
 473     if (next_transition >= 0 && visited_state == nullptr) {
 474       cur_state->execute_next(next_transition);
 475
 476       auto* transition  = cur_state->get_transition();
 477       XBT_DEBUG("Execute: %s", transition->to_string().c_str());
 478
 479       std::string req_str;
 480       if (dot_output != nullptr)
 481         req_str = api::get().request_get_dot_output(transition);
 482
 483       extension->handle_comm_pattern(transition, false);
 484
 485       /* Create the new expanded state */
 486       auto next_state = std::make_unique<State>();
 487       next_state->extension_set(new StateCommDet(extension));
 488
 489       bool all_communications_are_finished = true;
 490       for (size_t current_actor = 1; all_communications_are_finished && current_actor < maxpid; current_actor++) {
 491         if (not extension->incomplete_communications_pattern[current_actor].empty()) {
 492           XBT_DEBUG("Some communications are not finished, cannot stop the exploration! State not visited.");
 493           all_communications_are_finished = false;
 494         }
 495       }
 496
 497       /* If comm determinism verification, we cannot stop the exploration if some communications are not finished (at
 498        * least, data are transferred). These communications  are incomplete and they cannot be analyzed and compared
 499        * with the initial pattern. */
 500       bool compare_snapshots = extension->initial_communications_pattern_done && all_communications_are_finished;
 501
 502       if (_sg_mc_max_visited_states != 0)
 503         visited_state = visited_states_.addVisitedState(next_state->num_, next_state.get(), compare_snapshots);
 504       else
 505         visited_state = nullptr;
 506
 507       if (visited_state == nullptr) {
 508         /* Add all enabled actors to the interleave set of the next state */
 509         for (auto& act : api::get().get_actors()) {
 510           auto actor = act.copy.get_buffer();
 511           if (get_session().actor_is_enabled(actor->get_pid()))
 512             next_state->mark_todo(actor->get_pid());
 513         }
 514
 515         if (dot_output != nullptr)
 516           fprintf(dot_output, "\"%ld\" -> \"%ld\" [%s];\n", cur_state->num_, next_state->num_, req_str.c_str());
 517
 518       } else if (dot_output != nullptr)
 519         fprintf(dot_output, "\"%ld\" -> \"%ld\" [%s];\n", cur_state->num_,
 520                 visited_state->original_num == -1 ? visited_state->num : visited_state->original_num, req_str.c_str());
 521
 522       stack_.push_back(std::move(next_state));
 523     } else {
 524       if (stack_.size() > (std::size_t)_sg_mc_max_depth)
 525         XBT_WARN("/!\\ Max depth reached! /!\\ ");
 526       else if (visited_state != nullptr)
 527         XBT_DEBUG("State already visited (equal to state %ld), exploration stopped on this path.",
 528                   visited_state->original_num == -1 ? visited_state->num : visited_state->original_num);
 529       else
 530         XBT_DEBUG("There are no more processes to interleave. (depth %zu)", stack_.size());
 531
 532       extension->initial_communications_pattern_done = true;
 533
 534       /* Trash the current state, no longer needed */
 535       XBT_DEBUG("Delete state %ld at depth %zu", cur_state->num_, stack_.size());
 536       stack_.pop_back();
 537
 538       visited_state = nullptr;
 539
 540       api::get().mc_check_deadlock();
 541
 542       while (not stack_.empty()) {
 543         std::unique_ptr<State> state(std::move(stack_.back()));
 544         stack_.pop_back();
 545         if (state->count_todo() && stack_.size() < (std::size_t)_sg_mc_max_depth) {
 546           /* We found a back-tracking point, let's loop */
 547           XBT_DEBUG("Back-tracking to state %ld at depth %zu", state->num_, stack_.size() + 1);
 548           stack_.push_back(std::move(state));
 549
 550           this->restoreState();
 551
 552           XBT_DEBUG("Back-tracking to state %ld at depth %zu done", stack_.back()->num_, stack_.size());
 553
 554           break;
 555         } else {
 556           XBT_DEBUG("Delete state %ld at depth %zu", state->num_, stack_.size() + 1);
 557         }
 558       }
 559     }
 560   }
 561
 562   api::get().log_state();
 563 }
 564
 565 void CommunicationDeterminismChecker::run()
 566 {
 567   XBT_INFO("Check communication determinism");
 568   get_session().take_initial_snapshot();
 569
 570   this->prepare();
 571   this->real_run();
 572 }
 573
 574 Checker* create_communication_determinism_checker(Session* session)
 575 {
 576   return new CommunicationDeterminismChecker(session);
 577 }
 578
 579 } // namespace mc
 580 } // namespace simgrid