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(const 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(const Transition* transition, 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 void CommDetExtension::restore_communications_pattern(const simgrid::mc::State* state)
 170 {
 171   for (size_t i = 0; i < initial_communications_pattern.size(); i++)
 172     initial_communications_pattern[i].index_comm =
 173         state->extension<simgrid::mc::StateCommDet>()->communication_indices_[i];
 174
 175   const unsigned long maxpid = api::get().get_maxpid();
 176   for (unsigned long i = 0; i < maxpid; i++) {
 177     incomplete_communications_pattern[i].clear();
 178     for (simgrid::mc::PatternCommunication const& comm :
 179          state->extension<simgrid::mc::StateCommDet>()->incomplete_comm_pattern_[i])
 180       incomplete_communications_pattern[i].push_back(new simgrid::mc::PatternCommunication(comm.dup()));
 181   }
 182 }
 183
 184 static std::string print_determinism_result(simgrid::mc::CommPatternDifference diff, aid_t process,
 185                                             const simgrid::mc::PatternCommunication* comm, unsigned int cursor)
 186 {
 187   std::string type;
 188   std::string res;
 189
 190   if (comm->type == simgrid::mc::PatternCommunicationType::send)
 191     type = xbt::string_printf("The send communications pattern of the process %ld is different!", process - 1);
 192   else
 193     type = xbt::string_printf("The recv communications pattern of the process %ld is different!", process - 1);
 194
 195   using simgrid::mc::CommPatternDifference;
 196   switch (diff) {
 197     case CommPatternDifference::TYPE:
 198       res = xbt::string_printf("%s Different type for communication #%u", type.c_str(), cursor);
 199       break;
 200     case CommPatternDifference::RDV:
 201       res = xbt::string_printf("%s Different rdv for communication #%u", type.c_str(), cursor);
 202       break;
 203     case CommPatternDifference::TAG:
 204       res = xbt::string_printf("%s Different tag for communication #%u", type.c_str(), cursor);
 205       break;
 206     case CommPatternDifference::SRC_PROC:
 207       res = xbt::string_printf("%s Different source for communication #%u", type.c_str(), cursor);
 208       break;
 209     case CommPatternDifference::DST_PROC:
 210       res = xbt::string_printf("%s Different destination for communication #%u", type.c_str(), cursor);
 211       break;
 212     case CommPatternDifference::DATA_SIZE:
 213       res = xbt::string_printf("%s Different data size for communication #%u", type.c_str(), cursor);
 214       break;
 215     case CommPatternDifference::DATA:
 216       res = xbt::string_printf("%s Different data for communication #%u", type.c_str(), cursor);
 217       break;
 218     default:
 219       res = "";
 220       break;
 221   }
 222
 223   return res;
 224 }
 225
 226 void CommDetExtension::deterministic_comm_pattern(aid_t actor, const PatternCommunication* comm, bool backtracking)
 227 {
 228   if (not backtracking) {
 229     PatternCommunicationList& list = initial_communications_pattern[actor];
 230     CommPatternDifference diff     = compare_comm_pattern(list.list[list.index_comm].get(), comm);
 231
 232     if (diff != CommPatternDifference::NONE) {
 233       if (comm->type == PatternCommunicationType::send) {
 234         send_deterministic = false;
 235         send_diff          = print_determinism_result(diff, actor, comm, list.index_comm + 1);
 236       } else {
 237         recv_deterministic = false;
 238         recv_diff          = print_determinism_result(diff, actor, comm, list.index_comm + 1);
 239       }
 240       if (_sg_mc_send_determinism && not send_deterministic) {
 241         XBT_INFO("*********************************************************");
 242         XBT_INFO("***** Non-send-deterministic communications pattern *****");
 243         XBT_INFO("*********************************************************");
 244         XBT_INFO("%s", send_diff.c_str());
 245         api::get().log_state();
 246         api::get().mc_exit(SIMGRID_MC_EXIT_NON_DETERMINISM);
 247       } else if (_sg_mc_comms_determinism && (not send_deterministic && not recv_deterministic)) {
 248         XBT_INFO("****************************************************");
 249         XBT_INFO("***** Non-deterministic communications pattern *****");
 250         XBT_INFO("****************************************************");
 251         if (not send_diff.empty())
 252           XBT_INFO("%s", send_diff.c_str());
 253         if (not recv_diff.empty())
 254           XBT_INFO("%s", recv_diff.c_str());
 255         api::get().log_state();
 256         api::get().mc_exit(SIMGRID_MC_EXIT_NON_DETERMINISM);
 257       }
 258     }
 259   }
 260 }
 261
 262 /********** Non Static functions ***********/
 263
 264 void CommDetExtension::get_comm_pattern(smx_simcall_t request, CallType call_type, bool backtracking)
 265 {
 266   const smx_actor_t issuer                                     = api::get().simcall_get_issuer(request);
 267   const mc::PatternCommunicationList& initial_pattern          = initial_communications_pattern[issuer->get_pid()];
 268   const std::vector<PatternCommunication*>& incomplete_pattern = incomplete_communications_pattern[issuer->get_pid()];
 269
 270   auto pattern   = std::make_unique<PatternCommunication>();
 271   pattern->index = initial_pattern.index_comm + incomplete_pattern.size();
 272
 273   if (call_type == CallType::SEND) {
 274     /* Create comm pattern */
 275     pattern->type      = PatternCommunicationType::send;
 276     pattern->comm_addr = api::get().get_comm_isend_raw_addr(request);
 277     pattern->rdv       = api::get().get_pattern_comm_rdv(pattern->comm_addr);
 278     pattern->src_proc  = api::get().get_pattern_comm_src_proc(pattern->comm_addr);
 279
 280 #if HAVE_SMPI
 281     pattern->tag = api::get().get_smpi_request_tag(request, simgrid::simix::Simcall::COMM_ISEND);
 282 #endif
 283     pattern->data = api::get().get_pattern_comm_data(pattern->comm_addr);
 284
 285 #if HAVE_SMPI
 286     auto send_detached = api::get().check_send_request_detached(request);
 287     if (send_detached) {
 288       if (initial_communications_pattern_done) {
 289         /* Evaluate comm determinism */
 290         deterministic_comm_pattern(pattern->src_proc, pattern.get(), backtracking);
 291         initial_communications_pattern[pattern->src_proc].index_comm++;
 292       } else {
 293         /* Store comm pattern */
 294         initial_communications_pattern[pattern->src_proc].list.push_back(std::move(pattern));
 295       }
 296       return;
 297     }
 298 #endif
 299   } else if (call_type == CallType::RECV) {
 300     pattern->type = PatternCommunicationType::receive;
 301     pattern->comm_addr = api::get().get_comm_isend_raw_addr(request);
 302
 303 #if HAVE_SMPI
 304     pattern->tag = api::get().get_smpi_request_tag(request, simgrid::simix::Simcall::COMM_IRECV);
 305 #endif
 306     pattern->rdv = api::get().get_pattern_comm_rdv(pattern->comm_addr);
 307     pattern->dst_proc = api::get().get_pattern_comm_dst_proc(pattern->comm_addr);
 308   } else
 309     xbt_die("Unexpected call_type %i", (int)call_type);
 310
 311   XBT_DEBUG("Insert incomplete comm pattern %p for process %ld", pattern.get(), issuer->get_pid());
 312   incomplete_communications_pattern[issuer->get_pid()].push_back(pattern.release());
 313 }
 314
 315 void CommDetExtension::complete_comm_pattern(RemotePtr<kernel::activity::CommImpl> const& comm_addr, aid_t issuer,
 316                                              bool backtracking)
 317 {
 318   /* Complete comm pattern */
 319   std::vector<PatternCommunication*>& incomplete_pattern = incomplete_communications_pattern[issuer];
 320   auto current_comm_pattern =
 321       std::find_if(begin(incomplete_pattern), end(incomplete_pattern),
 322                    [&comm_addr](const PatternCommunication* comm) { return (comm->comm_addr == comm_addr); });
 323   xbt_assert(current_comm_pattern != std::end(incomplete_pattern), "Corresponding communication not found!");
 324   std::unique_ptr<PatternCommunication> comm_pattern(*current_comm_pattern);
 325
 326   comm_pattern->src_proc = api::get().get_src_actor(comm_addr)->get_pid();
 327   comm_pattern->dst_proc = api::get().get_dst_actor(comm_addr)->get_pid();
 328   if (comm_pattern->data.empty())
 329     comm_pattern->data = api::get().get_pattern_comm_data(comm_addr);
 330
 331   XBT_DEBUG("Remove incomplete comm pattern for process %ld at cursor %zd", issuer,
 332             std::distance(begin(incomplete_pattern), current_comm_pattern));
 333   incomplete_pattern.erase(current_comm_pattern);
 334
 335   if (initial_communications_pattern_done) {
 336     /* Evaluate comm determinism */
 337     deterministic_comm_pattern(issuer, comm_pattern.get(), backtracking);
 338     initial_communications_pattern[issuer].index_comm++;
 339   } else {
 340     /* Store comm pattern */
 341     initial_communications_pattern[issuer].list.push_back(std::move(comm_pattern));
 342   }
 343 }
 344
 345 CommunicationDeterminismChecker::CommunicationDeterminismChecker(Session* session) : Checker(session)
 346 {
 347   CommDetExtension::EXTENSION_ID = simgrid::mc::Checker::extension_create<CommDetExtension>();
 348   StateCommDet::EXTENSION_ID = simgrid::mc::State::extension_create<StateCommDet>();
 349 }
 350
 351 CommunicationDeterminismChecker::~CommunicationDeterminismChecker() = default;
 352
 353 RecordTrace CommunicationDeterminismChecker::get_record_trace() // override
 354 {
 355   RecordTrace res;
 356   for (auto const& state : stack_)
 357     res.push_back(state->get_transition());
 358   return res;
 359 }
 360
 361 std::vector<std::string> CommunicationDeterminismChecker::get_textual_trace() // override
 362 {
 363   std::vector<std::string> trace;
 364   for (auto const& state : stack_)
 365     trace.push_back(state->get_transition()->to_string());
 366   return trace;
 367 }
 368
 369 void CommunicationDeterminismChecker::log_state() // override
 370 {
 371   if (_sg_mc_comms_determinism) {
 372     if (extension<CommDetExtension>()->send_deterministic && not extension<CommDetExtension>()->recv_deterministic) {
 373       XBT_INFO("*******************************************************");
 374       XBT_INFO("**** Only-send-deterministic communication pattern ****");
 375       XBT_INFO("*******************************************************");
 376       XBT_INFO("%s", extension<CommDetExtension>()->recv_diff.c_str());
 377     }
 378     if (not extension<CommDetExtension>()->send_deterministic && extension<CommDetExtension>()->recv_deterministic) {
 379       XBT_INFO("*******************************************************");
 380       XBT_INFO("**** Only-recv-deterministic communication pattern ****");
 381       XBT_INFO("*******************************************************");
 382       XBT_INFO("%s", extension<CommDetExtension>()->send_diff.c_str());
 383     }
 384   }
 385   XBT_INFO("Expanded states = %ld", State::get_expanded_states());
 386   XBT_INFO("Visited states = %lu", api::get().mc_get_visited_states());
 387   XBT_INFO("Executed transitions = %lu", Transition::get_executed_transitions());
 388   XBT_INFO("Send-deterministic : %s", extension<CommDetExtension>()->send_deterministic ? "Yes" : "No");
 389   if (_sg_mc_comms_determinism)
 390     XBT_INFO("Recv-deterministic : %s", extension<CommDetExtension>()->recv_deterministic ? "Yes" : "No");
 391 }
 392
 393 void CommunicationDeterminismChecker::prepare()
 394 {
 395   auto initial_state = std::make_unique<State>();
 396   extension_set(new CommDetExtension());
 397   initial_state->extension_set(new StateCommDet(extension<CommDetExtension>()));
 398
 399   XBT_DEBUG("********* Start communication determinism verification *********");
 400
 401   /* Add all enabled actors to the interleave set of the initial state */
 402   for (auto& act : api::get().get_actors()) {
 403     auto actor = act.copy.get_buffer();
 404     if (get_session().actor_is_enabled(actor->get_pid()))
 405       initial_state->mark_todo(actor->get_pid());
 406   }
 407
 408   stack_.push_back(std::move(initial_state));
 409 }
 410
 411 void CommunicationDeterminismChecker::restoreState()
 412 {
 413   auto extension = this->extension<CommDetExtension>();
 414
 415   /* If asked to rollback on a state that has a snapshot, restore it */
 416   State* last_state = stack_.back().get();
 417   if (last_state->system_state_) {
 418     api::get().restore_state(last_state->system_state_);
 419     extension->restore_communications_pattern(last_state);
 420     return;
 421   }
 422
 423   /* if no snapshot, we need to restore the initial state and replay the transitions */
 424   get_session().restore_initial_state();
 425
 426   const unsigned long maxpid = api::get().get_maxpid();
 427   assert(maxpid == extension->incomplete_communications_pattern.size());
 428   assert(maxpid == extension->initial_communications_pattern.size());
 429   for (unsigned long j = 0; j < maxpid; j++) {
 430     extension->incomplete_communications_pattern[j].clear();
 431     extension->initial_communications_pattern[j].index_comm = 0;
 432   }
 433
 434   /* Traverse the stack from the state at position start and re-execute the transitions */
 435   for (std::unique_ptr<simgrid::mc::State> const& state : stack_) {
 436     if (state == stack_.back())
 437       break;
 438
 439     auto* transition = state->get_transition();
 440
 441     /* because we got a copy of the executed request, we have to fetch the real one,
 442        pointed by the request field of the issuer process */
 443     auto* saved_req          = &state->executed_req_;
 444     const smx_actor_t issuer = api::get().simcall_get_issuer(saved_req);
 445     smx_simcall_t req        = &issuer->simcall_;
 446
 447     /* TODO : handle test and testany simcalls */
 448     transition->replay();
 449     extension->handle_comm_pattern(transition, req, transition->times_considered_, true);
 450
 451     /* Update statistics */
 452     api::get().mc_inc_visited_states();
 453   }
 454 }
 455
 456 void CommDetExtension::handle_comm_pattern(const Transition* transition, smx_simcall_t req, int value,
 457                                            bool backtracking)
 458 {
 459   if (not _sg_mc_comms_determinism && not _sg_mc_send_determinism)
 460     return;
 461
 462   using simgrid::mc::CallType;
 463   switch (MC_get_call_type(req)) {
 464     case CallType::NONE:
 465       break;
 466     case CallType::SEND:
 467       get_comm_pattern(req, CallType::SEND, backtracking);
 468       break;
 469     case CallType::RECV:
 470       get_comm_pattern(req, CallType::RECV, backtracking);
 471       break;
 472     case CallType::WAIT: {
 473       auto comm_addr      = remote(simcall_comm_wait__getraw__comm(req));
 474       auto simcall_issuer = api::get().simcall_get_issuer(req);
 475       complete_comm_pattern(comm_addr, simcall_issuer->get_pid(), backtracking);
 476       break;
 477     }
 478     case CallType::WAITANY: {
 479       auto comm_addr = api::get().get_comm_waitany_raw_addr(req, value);
 480       auto simcall_issuer = api::get().simcall_get_issuer(req);
 481       complete_comm_pattern(comm_addr, simcall_issuer->get_pid(), backtracking);
 482     } break;
 483   default:
 484     xbt_die("Unexpected call type %i", (int)MC_get_call_type(req));
 485   }
 486 }
 487
 488 void CommunicationDeterminismChecker::real_run()
 489 {
 490   auto extension = this->extension<CommDetExtension>();
 491
 492   std::unique_ptr<VisitedState> visited_state = nullptr;
 493   const unsigned long maxpid                  = api::get().get_maxpid();
 494
 495   while (not stack_.empty()) {
 496     /* Get current state */
 497     State* cur_state = stack_.back().get();
 498
 499     XBT_DEBUG("**************************************************");
 500     XBT_DEBUG("Exploration depth = %zu (state = %ld, interleaved processes = %zu)", stack_.size(), cur_state->num_,
 501               cur_state->count_todo());
 502
 503     /* Update statistics */
 504     api::get().mc_inc_visited_states();
 505
 506     int next_transition = -1;
 507     if (stack_.size() <= (std::size_t)_sg_mc_max_depth)
 508       next_transition = cur_state->next_transition();
 509
 510     if (next_transition >= 0 && visited_state == nullptr) {
 511       cur_state->execute_next(next_transition);
 512
 513       auto* transition  = cur_state->get_transition();
 514       smx_simcall_t req = &cur_state->executed_req_;
 515
 516       XBT_DEBUG("Execute: %s", transition->to_string().c_str());
 517
 518       std::string req_str;
 519       if (dot_output != nullptr)
 520         req_str = api::get().request_get_dot_output(transition);
 521
 522       extension->handle_comm_pattern(transition, req, transition->times_considered_, false);
 523
 524       /* Create the new expanded state */
 525       auto next_state = std::make_unique<State>();
 526       next_state->extension_set(new StateCommDet(extension));
 527
 528       bool all_communications_are_finished = true;
 529       for (size_t current_actor = 1; all_communications_are_finished && current_actor < maxpid; current_actor++) {
 530         if (not extension->incomplete_communications_pattern[current_actor].empty()) {
 531           XBT_DEBUG("Some communications are not finished, cannot stop the exploration! State not visited.");
 532           all_communications_are_finished = false;
 533         }
 534       }
 535
 536       /* If comm determinism verification, we cannot stop the exploration if some communications are not finished (at
 537        * least, data are transferred). These communications  are incomplete and they cannot be analyzed and compared
 538        * with the initial pattern. */
 539       bool compare_snapshots = extension->initial_communications_pattern_done && all_communications_are_finished;
 540
 541       if (_sg_mc_max_visited_states != 0)
 542         visited_state = visited_states_.addVisitedState(next_state->num_, next_state.get(), compare_snapshots);
 543       else
 544         visited_state = nullptr;
 545
 546       if (visited_state == nullptr) {
 547         /* Add all enabled actors to the interleave set of the next state */
 548         for (auto& act : api::get().get_actors()) {
 549           auto actor = act.copy.get_buffer();
 550           if (get_session().actor_is_enabled(actor->get_pid()))
 551             next_state->mark_todo(actor->get_pid());
 552         }
 553
 554         if (dot_output != nullptr)
 555           fprintf(dot_output, "\"%ld\" -> \"%ld\" [%s];\n", cur_state->num_, next_state->num_, req_str.c_str());
 556
 557       } else if (dot_output != nullptr)
 558         fprintf(dot_output, "\"%ld\" -> \"%ld\" [%s];\n", cur_state->num_,
 559                 visited_state->original_num == -1 ? visited_state->num : visited_state->original_num, req_str.c_str());
 560
 561       stack_.push_back(std::move(next_state));
 562     } else {
 563       if (stack_.size() > (std::size_t)_sg_mc_max_depth)
 564         XBT_WARN("/!\\ Max depth reached! /!\\ ");
 565       else if (visited_state != nullptr)
 566         XBT_DEBUG("State already visited (equal to state %ld), exploration stopped on this path.",
 567                   visited_state->original_num == -1 ? visited_state->num : visited_state->original_num);
 568       else
 569         XBT_DEBUG("There are no more processes to interleave. (depth %zu)", stack_.size());
 570
 571       extension->initial_communications_pattern_done = true;
 572
 573       /* Trash the current state, no longer needed */
 574       XBT_DEBUG("Delete state %ld at depth %zu", cur_state->num_, stack_.size());
 575       stack_.pop_back();
 576
 577       visited_state = nullptr;
 578
 579       api::get().mc_check_deadlock();
 580
 581       while (not stack_.empty()) {
 582         std::unique_ptr<State> state(std::move(stack_.back()));
 583         stack_.pop_back();
 584         if (state->count_todo() && stack_.size() < (std::size_t)_sg_mc_max_depth) {
 585           /* We found a back-tracking point, let's loop */
 586           XBT_DEBUG("Back-tracking to state %ld at depth %zu", state->num_, stack_.size() + 1);
 587           stack_.push_back(std::move(state));
 588
 589           this->restoreState();
 590
 591           XBT_DEBUG("Back-tracking to state %ld at depth %zu done", stack_.back()->num_, stack_.size());
 592
 593           break;
 594         } else {
 595           XBT_DEBUG("Delete state %ld at depth %zu", state->num_, stack_.size() + 1);
 596         }
 597       }
 598     }
 599   }
 600
 601   api::get().log_state();
 602 }
 603
 604 void CommunicationDeterminismChecker::run()
 605 {
 606   XBT_INFO("Check communication determinism");
 607   get_session().take_initial_snapshot();
 608
 609   this->prepare();
 610   this->real_run();
 611 }
 612
 613 Checker* create_communication_determinism_checker(Session* session)
 614 {
 615   return new CommunicationDeterminismChecker(session);
 616 }
 617
 618 } // namespace mc
 619 } // namespace simgrid