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