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/mc_config.hpp"
  10 #include "src/mc/mc_exit.hpp"
  11 #include "src/mc/mc_private.hpp"
  12
  13 #include <cstdint>
  14
  15 using api = simgrid::mc::Api;
  16
  17 XBT_LOG_NEW_DEFAULT_SUBCATEGORY(mc_comm_determinism, mc, "Logging specific to MC communication determinism detection");
  18
  19 namespace simgrid {
  20 namespace mc {
  21
  22 enum class CallType { NONE, SEND, RECV, WAIT, WAITANY };
  23 enum class CommPatternDifference { NONE, TYPE, RDV, TAG, SRC_PROC, DST_PROC, DATA_SIZE, DATA };
  24 enum class PatternCommunicationType {
  25   none    = 0,
  26   send    = 1,
  27   receive = 2,
  28 };
  29
  30 class PatternCommunication {
  31 public:
  32   int num = 0;
  33   RemotePtr<simgrid::kernel::activity::CommImpl> comm_addr{nullptr};
  34   PatternCommunicationType type = PatternCommunicationType::send;
  35   unsigned long src_proc        = 0;
  36   unsigned long dst_proc        = 0;
  37   std::string rdv;
  38   std::vector<char> data;
  39   int tag   = 0;
  40   int index = 0;
  41
  42   PatternCommunication dup() const
  43   {
  44     simgrid::mc::PatternCommunication res;
  45     // num?
  46     res.comm_addr = this->comm_addr;
  47     res.type      = this->type;
  48     // src_proc?
  49     // dst_proc?
  50     res.dst_proc = this->dst_proc;
  51     res.rdv      = this->rdv;
  52     res.data     = this->data;
  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 static inline simgrid::mc::CallType MC_get_call_type(const s_smx_simcall* req)
  65 {
  66   using simgrid::mc::CallType;
  67   using simgrid::simix::Simcall;
  68   switch (req->call_) {
  69     case Simcall::COMM_ISEND:
  70       return CallType::SEND;
  71     case Simcall::COMM_IRECV:
  72       return CallType::RECV;
  73     case Simcall::COMM_WAIT:
  74       return CallType::WAIT;
  75     case Simcall::COMM_WAITANY:
  76       return CallType::WAITANY;
  77     default:
  78       return CallType::NONE;
  79   }
  80 }
  81
  82 /********** Checker extension **********/
  83
  84 struct CommDetExtension {
  85   static simgrid::xbt::Extension<simgrid::mc::Checker, CommDetExtension> EXTENSION_ID;
  86
  87   CommDetExtension()
  88   {
  89     const unsigned long maxpid = api::get().get_maxpid();
  90
  91     initial_communications_pattern.resize(maxpid);
  92     incomplete_communications_pattern.resize(maxpid);
  93   }
  94
  95   std::vector<simgrid::mc::PatternCommunicationList> initial_communications_pattern;
  96   std::vector<std::vector<simgrid::mc::PatternCommunication*>> incomplete_communications_pattern;
  97
  98   bool initial_communications_pattern_done = false;
  99   bool recv_deterministic                  = true;
 100   bool send_deterministic                  = true;
 101   std::string send_diff;
 102   std::string recv_diff;
 103
 104   void restore_communications_pattern(simgrid::mc::State* state);
 105   void deterministic_comm_pattern(aid_t process, const PatternCommunication* comm, bool backtracking);
 106   void get_comm_pattern(smx_simcall_t request, CallType call_type, bool backtracking);
 107   void complete_comm_pattern(RemotePtr<kernel::activity::CommImpl> const& comm_addr, aid_t issuer, bool backtracking);
 108   void handle_comm_pattern(simgrid::mc::CallType call_type, smx_simcall_t req, int value, bool backtracking);
 109 };
 110 simgrid::xbt::Extension<simgrid::mc::Checker, CommDetExtension> CommDetExtension::EXTENSION_ID;
 111 /********** State Extension ***********/
 112
 113 class StateCommDet {
 114   CommDetExtension* checker_;
 115
 116 public:
 117   std::vector<std::vector<simgrid::mc::PatternCommunication>> incomplete_comm_pattern_;
 118   std::vector<unsigned> communication_indices_;
 119
 120   static simgrid::xbt::Extension<simgrid::mc::State, StateCommDet> EXTENSION_ID;
 121   explicit StateCommDet(CommDetExtension* checker) : checker_(checker)
 122   {
 123     copy_incomplete_comm_pattern();
 124     copy_index_comm_pattern();
 125   }
 126
 127   void copy_incomplete_comm_pattern()
 128   {
 129     incomplete_comm_pattern_.clear();
 130     const unsigned long maxpid = api::get().get_maxpid();
 131     for (unsigned long i = 0; i < maxpid; i++) {
 132       std::vector<simgrid::mc::PatternCommunication> res;
 133       for (auto const& comm : checker_->incomplete_communications_pattern[i])
 134         res.push_back(comm->dup());
 135       incomplete_comm_pattern_.push_back(std::move(res));
 136     }
 137   }
 138
 139   void copy_index_comm_pattern()
 140   {
 141     communication_indices_.clear();
 142     for (auto const& list_process_comm : checker_->initial_communications_pattern)
 143       this->communication_indices_.push_back(list_process_comm.index_comm);
 144   }
 145 };
 146 simgrid::xbt::Extension<simgrid::mc::State, StateCommDet> StateCommDet::EXTENSION_ID;
 147
 148 static simgrid::mc::CommPatternDifference compare_comm_pattern(const simgrid::mc::PatternCommunication* comm1,
 149                                                                const simgrid::mc::PatternCommunication* comm2)
 150 {
 151   using simgrid::mc::CommPatternDifference;
 152   if (comm1->type != comm2->type)
 153     return CommPatternDifference::TYPE;
 154   if (comm1->rdv != comm2->rdv)
 155     return CommPatternDifference::RDV;
 156   if (comm1->src_proc != comm2->src_proc)
 157     return CommPatternDifference::SRC_PROC;
 158   if (comm1->dst_proc != comm2->dst_proc)
 159     return CommPatternDifference::DST_PROC;
 160   if (comm1->tag != comm2->tag)
 161     return CommPatternDifference::TAG;
 162   if (comm1->data.size() != comm2->data.size())
 163     return CommPatternDifference::DATA_SIZE;
 164   if (comm1->data != comm2->data)
 165     return CommPatternDifference::DATA;
 166   return CommPatternDifference::NONE;
 167 }
 168
 169 static void patterns_copy(std::vector<simgrid::mc::PatternCommunication*>& dest,
 170                              std::vector<simgrid::mc::PatternCommunication> const& source)
 171 {
 172   dest.clear();
 173   for (simgrid::mc::PatternCommunication const& comm : source) {
 174     auto* copy_comm = new simgrid::mc::PatternCommunication(comm.dup());
 175     dest.push_back(copy_comm);
 176   }
 177 }
 178
 179 void CommDetExtension::restore_communications_pattern(simgrid::mc::State* state)
 180 {
 181   for (size_t i = 0; i < initial_communications_pattern.size(); i++)
 182     initial_communications_pattern[i].index_comm =
 183         state->extension<simgrid::mc::StateCommDet>()->communication_indices_[i];
 184
 185   const unsigned long maxpid = api::get().get_maxpid();
 186   for (unsigned long i = 0; i < maxpid; i++)
 187     patterns_copy(incomplete_communications_pattern[i],
 188                   state->extension<simgrid::mc::StateCommDet>()->incomplete_comm_pattern_[i]);
 189 }
 190
 191 static std::string print_determinism_result(simgrid::mc::CommPatternDifference diff, aid_t process,
 192                                             const simgrid::mc::PatternCommunication* comm, unsigned int cursor)
 193 {
 194   std::string type;
 195   std::string res;
 196
 197   if (comm->type == simgrid::mc::PatternCommunicationType::send)
 198     type = xbt::string_printf("The send communications pattern of the process %ld is different!", process - 1);
 199   else
 200     type = xbt::string_printf("The recv communications pattern of the process %ld is different!", process - 1);
 201
 202   using simgrid::mc::CommPatternDifference;
 203   switch (diff) {
 204     case CommPatternDifference::TYPE:
 205       res = xbt::string_printf("%s Different type for communication #%u", type.c_str(), cursor);
 206       break;
 207     case CommPatternDifference::RDV:
 208       res = xbt::string_printf("%s Different rdv for communication #%u", type.c_str(), cursor);
 209       break;
 210     case CommPatternDifference::TAG:
 211       res = xbt::string_printf("%s Different tag for communication #%u", type.c_str(), cursor);
 212       break;
 213     case CommPatternDifference::SRC_PROC:
 214       res = xbt::string_printf("%s Different source for communication #%u", type.c_str(), cursor);
 215       break;
 216     case CommPatternDifference::DST_PROC:
 217       res = xbt::string_printf("%s Different destination for communication #%u", type.c_str(), cursor);
 218       break;
 219     case CommPatternDifference::DATA_SIZE:
 220       res = xbt::string_printf("%s Different data size for communication #%u", type.c_str(), cursor);
 221       break;
 222     case CommPatternDifference::DATA:
 223       res = xbt::string_printf("%s Different data for communication #%u", type.c_str(), cursor);
 224       break;
 225     default:
 226       res = "";
 227       break;
 228   }
 229
 230   return res;
 231 }
 232
 233 static void update_comm_pattern(simgrid::mc::PatternCommunication* comm_pattern,
 234                                 simgrid::mc::RemotePtr<simgrid::kernel::activity::CommImpl> const& comm_addr)
 235 {
 236   auto src_proc = api::get().get_src_actor(comm_addr);
 237   auto dst_proc = api::get().get_dst_actor(comm_addr);
 238   comm_pattern->src_proc = src_proc->get_pid();
 239   comm_pattern->dst_proc = dst_proc->get_pid();
 240
 241   if (comm_pattern->data.empty()) {
 242     comm_pattern->data = api::get().get_pattern_comm_data(comm_addr);
 243   }
 244 }
 245
 246 void CommDetExtension::deterministic_comm_pattern(aid_t actor, const PatternCommunication* comm, bool backtracking)
 247 {
 248   if (not backtracking) {
 249     PatternCommunicationList& list = initial_communications_pattern[actor];
 250     CommPatternDifference diff     = compare_comm_pattern(list.list[list.index_comm].get(), comm);
 251
 252     if (diff != CommPatternDifference::NONE) {
 253       if (comm->type == PatternCommunicationType::send) {
 254         send_deterministic = false;
 255         send_diff          = print_determinism_result(diff, actor, comm, list.index_comm + 1);
 256       } else {
 257         recv_deterministic = false;
 258         recv_diff          = print_determinism_result(diff, actor, comm, list.index_comm + 1);
 259       }
 260       if (_sg_mc_send_determinism && not send_deterministic) {
 261         XBT_INFO("*********************************************************");
 262         XBT_INFO("***** Non-send-deterministic communications pattern *****");
 263         XBT_INFO("*********************************************************");
 264         XBT_INFO("%s", send_diff.c_str());
 265         api::get().log_state();
 266         api::get().mc_exit(SIMGRID_MC_EXIT_NON_DETERMINISM);
 267       } else if (_sg_mc_comms_determinism && (not send_deterministic && not recv_deterministic)) {
 268         XBT_INFO("****************************************************");
 269         XBT_INFO("***** Non-deterministic communications pattern *****");
 270         XBT_INFO("****************************************************");
 271         if (not send_diff.empty())
 272           XBT_INFO("%s", send_diff.c_str());
 273         if (not recv_diff.empty())
 274           XBT_INFO("%s", recv_diff.c_str());
 275         api::get().log_state();
 276         api::get().mc_exit(SIMGRID_MC_EXIT_NON_DETERMINISM);
 277       }
 278     }
 279   }
 280 }
 281
 282 /********** Non Static functions ***********/
 283
 284 void CommDetExtension::get_comm_pattern(smx_simcall_t request, CallType call_type, bool backtracking)
 285 {
 286   const smx_actor_t issuer                                     = api::get().simcall_get_issuer(request);
 287   const mc::PatternCommunicationList& initial_pattern          = initial_communications_pattern[issuer->get_pid()];
 288   const std::vector<PatternCommunication*>& incomplete_pattern = incomplete_communications_pattern[issuer->get_pid()];
 289
 290   auto pattern   = std::make_unique<PatternCommunication>();
 291   pattern->index = initial_pattern.index_comm + incomplete_pattern.size();
 292
 293   if (call_type == CallType::SEND) {
 294     /* Create comm pattern */
 295     pattern->type      = PatternCommunicationType::send;
 296     pattern->comm_addr = api::get().get_comm_isend_raw_addr(request);
 297     pattern->rdv       = api::get().get_pattern_comm_rdv(pattern->comm_addr);
 298     pattern->src_proc  = api::get().get_pattern_comm_src_proc(pattern->comm_addr);
 299
 300 #if HAVE_SMPI
 301     pattern->tag = api::get().get_smpi_request_tag(request, simgrid::simix::Simcall::COMM_ISEND);
 302 #endif
 303     pattern->data = api::get().get_pattern_comm_data(pattern->comm_addr);
 304
 305 #if HAVE_SMPI
 306     auto send_detached = api::get().check_send_request_detached(request);
 307     if (send_detached) {
 308       if (initial_communications_pattern_done) {
 309         /* Evaluate comm determinism */
 310         deterministic_comm_pattern(pattern->src_proc, pattern.get(), backtracking);
 311         initial_communications_pattern[pattern->src_proc].index_comm++;
 312       } else {
 313         /* Store comm pattern */
 314         initial_communications_pattern[pattern->src_proc].list.push_back(std::move(pattern));
 315       }
 316       return;
 317     }
 318 #endif
 319   } else if (call_type == CallType::RECV) {
 320     pattern->type = PatternCommunicationType::receive;
 321     pattern->comm_addr = api::get().get_comm_isend_raw_addr(request);
 322
 323 #if HAVE_SMPI
 324     pattern->tag = api::get().get_smpi_request_tag(request, simgrid::simix::Simcall::COMM_IRECV);
 325 #endif
 326     pattern->rdv = api::get().get_pattern_comm_rdv(pattern->comm_addr);
 327     pattern->dst_proc = api::get().get_pattern_comm_dst_proc(pattern->comm_addr);
 328   } else
 329     xbt_die("Unexpected call_type %i", (int)call_type);
 330
 331   XBT_DEBUG("Insert incomplete comm pattern %p for process %ld", pattern.get(), issuer->get_pid());
 332   incomplete_communications_pattern[issuer->get_pid()].push_back(pattern.release());
 333 }
 334
 335 void CommDetExtension::complete_comm_pattern(RemotePtr<kernel::activity::CommImpl> const& comm_addr, aid_t issuer,
 336                                              bool backtracking)
 337 {
 338   /* Complete comm pattern */
 339   std::vector<PatternCommunication*>& incomplete_pattern = incomplete_communications_pattern[issuer];
 340   auto current_comm_pattern =
 341       std::find_if(begin(incomplete_pattern), end(incomplete_pattern),
 342                    [&comm_addr](const PatternCommunication* comm) { return (comm->comm_addr == comm_addr); });
 343   xbt_assert(current_comm_pattern != std::end(incomplete_pattern), "Corresponding communication not found!");
 344
 345   update_comm_pattern(*current_comm_pattern, comm_addr);
 346   std::unique_ptr<PatternCommunication> comm_pattern(*current_comm_pattern);
 347   XBT_DEBUG("Remove incomplete comm pattern for process %ld at cursor %zd", issuer,
 348             std::distance(begin(incomplete_pattern), current_comm_pattern));
 349   incomplete_pattern.erase(current_comm_pattern);
 350
 351   if (initial_communications_pattern_done) {
 352     /* Evaluate comm determinism */
 353     deterministic_comm_pattern(issuer, comm_pattern.get(), backtracking);
 354     initial_communications_pattern[issuer].index_comm++;
 355   } else {
 356     /* Store comm pattern */
 357     initial_communications_pattern[issuer].list.push_back(std::move(comm_pattern));
 358   }
 359 }
 360
 361 CommunicationDeterminismChecker::CommunicationDeterminismChecker(Session* session) : Checker(session)
 362 {
 363   CommDetExtension::EXTENSION_ID = simgrid::mc::Checker::extension_create<CommDetExtension>();
 364   StateCommDet::EXTENSION_ID = simgrid::mc::State::extension_create<StateCommDet>();
 365 }
 366
 367 CommunicationDeterminismChecker::~CommunicationDeterminismChecker() = default;
 368
 369 RecordTrace CommunicationDeterminismChecker::get_record_trace() // override
 370 {
 371   RecordTrace res;
 372   for (auto const& state : stack_)
 373     res.push_back(state->get_transition());
 374   return res;
 375 }
 376
 377 std::vector<std::string> CommunicationDeterminismChecker::get_textual_trace() // override
 378 {
 379   std::vector<std::string> trace;
 380   for (auto const& state : stack_)
 381     trace.push_back(state->get_transition()->to_string());
 382   return trace;
 383 }
 384
 385 void CommunicationDeterminismChecker::log_state() // override
 386 {
 387   if (_sg_mc_comms_determinism) {
 388     if (extension<CommDetExtension>()->send_deterministic && not extension<CommDetExtension>()->recv_deterministic) {
 389       XBT_INFO("*******************************************************");
 390       XBT_INFO("**** Only-send-deterministic communication pattern ****");
 391       XBT_INFO("*******************************************************");
 392       XBT_INFO("%s", extension<CommDetExtension>()->recv_diff.c_str());
 393     }
 394     if (not extension<CommDetExtension>()->send_deterministic && extension<CommDetExtension>()->recv_deterministic) {
 395       XBT_INFO("*******************************************************");
 396       XBT_INFO("**** Only-recv-deterministic communication pattern ****");
 397       XBT_INFO("*******************************************************");
 398       XBT_INFO("%s", extension<CommDetExtension>()->send_diff.c_str());
 399     }
 400   }
 401   XBT_INFO("Expanded states = %ld", State::get_expanded_states());
 402   XBT_INFO("Visited states = %lu", api::get().mc_get_visited_states());
 403   XBT_INFO("Executed transitions = %lu", Transition::get_executed_transitions());
 404   XBT_INFO("Send-deterministic : %s", extension<CommDetExtension>()->send_deterministic ? "Yes" : "No");
 405   if (_sg_mc_comms_determinism)
 406     XBT_INFO("Recv-deterministic : %s", extension<CommDetExtension>()->recv_deterministic ? "Yes" : "No");
 407 }
 408
 409 void CommunicationDeterminismChecker::prepare()
 410 {
 411   auto initial_state = std::make_unique<State>();
 412   extension_set(new CommDetExtension());
 413   initial_state->extension_set(new StateCommDet(extension<CommDetExtension>()));
 414
 415   XBT_DEBUG("********* Start communication determinism verification *********");
 416
 417   /* Add all enabled actors to the interleave set of the initial state */
 418   for (auto& act : api::get().get_actors()) {
 419     auto actor = act.copy.get_buffer();
 420     if (get_session().actor_is_enabled(actor->get_pid()))
 421       initial_state->mark_todo(actor->get_pid());
 422   }
 423
 424   stack_.push_back(std::move(initial_state));
 425 }
 426
 427 void CommunicationDeterminismChecker::restoreState()
 428 {
 429   auto extension = this->extension<CommDetExtension>();
 430
 431   /* Intermediate backtracking */
 432   State* last_state = stack_.back().get();
 433   if (last_state->system_state_) {
 434     api::get().restore_state(last_state->system_state_);
 435     extension->restore_communications_pattern(last_state);
 436     return;
 437   }
 438
 439   get_session().restore_initial_state();
 440
 441   const unsigned long maxpid = api::get().get_maxpid();
 442   assert(maxpid == extension->incomplete_communications_pattern.size());
 443   assert(maxpid == extension->initial_communications_pattern.size());
 444   for (unsigned long j = 0; j < maxpid; j++) {
 445     extension->incomplete_communications_pattern[j].clear();
 446     extension->initial_communications_pattern[j].index_comm = 0;
 447   }
 448
 449   /* Traverse the stack from the state at position start and re-execute the transitions */
 450   for (std::unique_ptr<simgrid::mc::State> const& state : stack_) {
 451     if (state == stack_.back())
 452       break;
 453
 454     int req_num                    = state->get_transition()->times_considered_;
 455     const s_smx_simcall* saved_req = &state->executed_req_;
 456     xbt_assert(saved_req);
 457
 458     /* because we got a copy of the executed request, we have to fetch the
 459        real one, pointed by the request field of the issuer process */
 460
 461     const smx_actor_t issuer = api::get().simcall_get_issuer(saved_req);
 462     smx_simcall_t req        = &issuer->simcall_;
 463
 464     /* TODO : handle test and testany simcalls */
 465     CallType call = MC_get_call_type(req);
 466     state->get_transition()->replay();
 467     extension->handle_comm_pattern(call, req, req_num, true);
 468
 469     /* Update statistics */
 470     api::get().mc_inc_visited_states();
 471   }
 472 }
 473
 474 void CommDetExtension::handle_comm_pattern(simgrid::mc::CallType call_type, smx_simcall_t req, int value,
 475                                            bool backtracking)
 476 {
 477   using simgrid::mc::CallType;
 478   switch(call_type) {
 479     case CallType::NONE:
 480       break;
 481     case CallType::SEND:
 482     case CallType::RECV:
 483       get_comm_pattern(req, call_type, backtracking);
 484       break;
 485     case CallType::WAIT:
 486     case CallType::WAITANY: {
 487       RemotePtr<simgrid::kernel::activity::CommImpl> comm_addr;
 488       if (call_type == CallType::WAIT)
 489         comm_addr = remote(simcall_comm_wait__getraw__comm(req));
 490       else
 491         comm_addr = api::get().get_comm_waitany_raw_addr(req, value);
 492       auto simcall_issuer = api::get().simcall_get_issuer(req);
 493       complete_comm_pattern(comm_addr, simcall_issuer->get_pid(), backtracking);
 494     } break;
 495   default:
 496     xbt_die("Unexpected call type %i", (int)call_type);
 497   }
 498 }
 499
 500 void CommunicationDeterminismChecker::real_run()
 501 {
 502   auto extension = this->extension<CommDetExtension>();
 503
 504   std::unique_ptr<VisitedState> visited_state = nullptr;
 505   const unsigned long maxpid                  = api::get().get_maxpid();
 506
 507   while (not stack_.empty()) {
 508     /* Get current state */
 509     State* cur_state = stack_.back().get();
 510
 511     XBT_DEBUG("**************************************************");
 512     XBT_DEBUG("Exploration depth = %zu (state = %ld, interleaved processes = %zu)", stack_.size(), cur_state->num_,
 513               cur_state->count_todo());
 514
 515     /* Update statistics */
 516     api::get().mc_inc_visited_states();
 517
 518     int next_transition = -1;
 519     if (stack_.size() <= (std::size_t)_sg_mc_max_depth)
 520       next_transition = cur_state->next_transition();
 521
 522     if (next_transition >= 0 && visited_state == nullptr) {
 523       cur_state->execute_next(next_transition);
 524
 525       int req_num       = cur_state->get_transition()->times_considered_;
 526       smx_simcall_t req = &cur_state->executed_req_;
 527
 528       XBT_DEBUG("Execute: %s", cur_state->get_transition()->to_string().c_str());
 529
 530       std::string req_str;
 531       if (dot_output != nullptr)
 532         req_str = api::get().request_get_dot_output(cur_state->get_transition());
 533
 534       /* TODO : handle test and testany simcalls */
 535       CallType call = CallType::NONE;
 536       if (_sg_mc_comms_determinism || _sg_mc_send_determinism)
 537         call = MC_get_call_type(req);
 538
 539       extension->handle_comm_pattern(call, req, req_num, false);
 540
 541       /* Create the new expanded state */
 542       auto next_state = std::make_unique<State>();
 543       next_state->extension_set(new StateCommDet(extension));
 544
 545       bool all_communications_are_finished = true;
 546       for (size_t current_actor = 1; all_communications_are_finished && current_actor < maxpid; current_actor++) {
 547         if (not extension->incomplete_communications_pattern[current_actor].empty()) {
 548           XBT_DEBUG("Some communications are not finished, cannot stop the exploration! State not visited.");
 549           all_communications_are_finished = false;
 550         }
 551       }
 552
 553       /* If comm determinism verification, we cannot stop the exploration if some communications are not finished (at
 554        * least, data are transferred). These communications  are incomplete and they cannot be analyzed and compared
 555        * with the initial pattern. */
 556       bool compare_snapshots = extension->initial_communications_pattern_done && all_communications_are_finished;
 557
 558       if (_sg_mc_max_visited_states != 0)
 559         visited_state = visited_states_.addVisitedState(next_state->num_, next_state.get(), compare_snapshots);
 560       else
 561         visited_state = nullptr;
 562
 563       if (visited_state == nullptr) {
 564         /* Add all enabled actors to the interleave set of the next state */
 565         for (auto& act : api::get().get_actors()) {
 566           auto actor = act.copy.get_buffer();
 567           if (get_session().actor_is_enabled(actor->get_pid()))
 568             next_state->mark_todo(actor->get_pid());
 569         }
 570
 571         if (dot_output != nullptr)
 572           fprintf(dot_output, "\"%ld\" -> \"%ld\" [%s];\n", cur_state->num_, next_state->num_, req_str.c_str());
 573
 574       } else if (dot_output != nullptr)
 575         fprintf(dot_output, "\"%ld\" -> \"%ld\" [%s];\n", cur_state->num_,
 576                 visited_state->original_num == -1 ? visited_state->num : visited_state->original_num, req_str.c_str());
 577
 578       stack_.push_back(std::move(next_state));
 579     } else {
 580       if (stack_.size() > (std::size_t)_sg_mc_max_depth)
 581         XBT_WARN("/!\\ Max depth reached! /!\\ ");
 582       else if (visited_state != nullptr)
 583         XBT_DEBUG("State already visited (equal to state %ld), exploration stopped on this path.",
 584                   visited_state->original_num == -1 ? visited_state->num : visited_state->original_num);
 585       else
 586         XBT_DEBUG("There are no more processes to interleave. (depth %zu)", stack_.size());
 587
 588       extension->initial_communications_pattern_done = true;
 589
 590       /* Trash the current state, no longer needed */
 591       XBT_DEBUG("Delete state %ld at depth %zu", cur_state->num_, stack_.size());
 592       stack_.pop_back();
 593
 594       visited_state = nullptr;
 595
 596       api::get().mc_check_deadlock();
 597
 598       while (not stack_.empty()) {
 599         std::unique_ptr<State> state(std::move(stack_.back()));
 600         stack_.pop_back();
 601         if (state->count_todo() && stack_.size() < (std::size_t)_sg_mc_max_depth) {
 602           /* We found a back-tracking point, let's loop */
 603           XBT_DEBUG("Back-tracking to state %ld at depth %zu", state->num_, stack_.size() + 1);
 604           stack_.push_back(std::move(state));
 605
 606           this->restoreState();
 607
 608           XBT_DEBUG("Back-tracking to state %ld at depth %zu done", stack_.back()->num_, stack_.size());
 609
 610           break;
 611         } else {
 612           XBT_DEBUG("Delete state %ld at depth %zu", state->num_, stack_.size() + 1);
 613         }
 614       }
 615     }
 616   }
 617
 618   api::get().log_state();
 619 }
 620
 621 void CommunicationDeterminismChecker::run()
 622 {
 623   XBT_INFO("Check communication determinism");
 624   get_session().take_initial_snapshot();
 625
 626   this->prepare();
 627   this->real_run();
 628 }
 629
 630 Checker* create_communication_determinism_checker(Session* session)
 631 {
 632   return new CommunicationDeterminismChecker(session);
 633 }
 634
 635 } // namespace mc
 636 } // namespace simgrid