src/mc/checker/CommunicationDeterminismChecker.cpp

   1 /* Copyright (c) 2008-2020. 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 #include "src/mc/mc_request.hpp"
  13 #include "src/mc/mc_smx.hpp"
  14
  15 #if HAVE_SMPI
  16 #include "smpi_request.hpp"
  17 #endif
  18
  19 #include <cstdint>
  20
  21 using simgrid::mc::remote;
  22
  23 XBT_LOG_NEW_DEFAULT_SUBCATEGORY(mc_comm_determinism, mc, "Logging specific to MC communication determinism detection");
  24
  25 /********** Global variables **********/
  26
  27 std::vector<simgrid::mc::PatternCommunicationList> initial_communications_pattern;
  28 std::vector<std::vector<simgrid::mc::PatternCommunication*>> incomplete_communications_pattern;
  29
  30 /********** Static functions ***********/
  31
  32 static e_mc_comm_pattern_difference_t compare_comm_pattern(const simgrid::mc::PatternCommunication* comm1,
  33                                                            const simgrid::mc::PatternCommunication* comm2)
  34 {
  35   if(comm1->type != comm2->type)
  36     return TYPE_DIFF;
  37   if (comm1->rdv != comm2->rdv)
  38     return RDV_DIFF;
  39   if (comm1->src_proc != comm2->src_proc)
  40     return SRC_PROC_DIFF;
  41   if (comm1->dst_proc != comm2->dst_proc)
  42     return DST_PROC_DIFF;
  43   if (comm1->tag != comm2->tag)
  44     return TAG_DIFF;
  45   if (comm1->data.size() != comm2->data.size())
  46     return DATA_SIZE_DIFF;
  47   if (comm1->data != comm2->data)
  48     return DATA_DIFF;
  49   return NONE_DIFF;
  50 }
  51
  52 static char* print_determinism_result(e_mc_comm_pattern_difference_t diff, int process,
  53                                       const simgrid::mc::PatternCommunication* comm, unsigned int cursor)
  54 {
  55   char* type;
  56   char* res;
  57
  58   if (comm->type == simgrid::mc::PatternCommunicationType::send)
  59     type = bprintf("The send communications pattern of the process %d is different!", process - 1);
  60   else
  61     type = bprintf("The recv communications pattern of the process %d is different!", process - 1);
  62
  63   switch(diff) {
  64   case TYPE_DIFF:
  65     res = bprintf("%s Different type for communication #%u", type, cursor);
  66     break;
  67   case RDV_DIFF:
  68     res = bprintf("%s Different rdv for communication #%u", type, cursor);
  69     break;
  70   case TAG_DIFF:
  71     res = bprintf("%s Different tag for communication #%u", type, cursor);
  72     break;
  73   case SRC_PROC_DIFF:
  74     res = bprintf("%s Different source for communication #%u", type, cursor);
  75     break;
  76   case DST_PROC_DIFF:
  77     res = bprintf("%s Different destination for communication #%u", type, cursor);
  78     break;
  79   case DATA_SIZE_DIFF:
  80     res = bprintf("%s Different data size for communication #%u", type, cursor);
  81     break;
  82   case DATA_DIFF:
  83     res = bprintf("%s Different data for communication #%u", type, cursor);
  84     break;
  85   default:
  86     res = nullptr;
  87     break;
  88   }
  89
  90   return res;
  91 }
  92
  93 static void update_comm_pattern(simgrid::mc::PatternCommunication* comm_pattern,
  94                                 simgrid::mc::RemotePtr<simgrid::kernel::activity::CommImpl> comm_addr)
  95 {
  96   // HACK, type punning
  97   simgrid::mc::Remote<simgrid::kernel::activity::CommImpl> temp_comm;
  98   mc_model_checker->get_remote_simulation().read(temp_comm, comm_addr);
  99   const simgrid::kernel::activity::CommImpl* comm = temp_comm.get_buffer();
 100
 101   smx_actor_t src_proc =
 102       mc_model_checker->get_remote_simulation().resolve_actor(simgrid::mc::remote(comm->src_actor_.get()));
 103   smx_actor_t dst_proc =
 104       mc_model_checker->get_remote_simulation().resolve_actor(simgrid::mc::remote(comm->dst_actor_.get()));
 105   comm_pattern->src_proc = src_proc->get_pid();
 106   comm_pattern->dst_proc = dst_proc->get_pid();
 107   comm_pattern->src_host = MC_smx_actor_get_host_name(src_proc);
 108   comm_pattern->dst_host = MC_smx_actor_get_host_name(dst_proc);
 109   if (comm_pattern->data.size() == 0 && comm->src_buff_ != nullptr) {
 110     size_t buff_size;
 111     mc_model_checker->get_remote_simulation().read(&buff_size, remote(comm->dst_buff_size_));
 112     comm_pattern->data.resize(buff_size);
 113     mc_model_checker->get_remote_simulation().read_bytes(comm_pattern->data.data(), comm_pattern->data.size(),
 114                                                          remote(comm->src_buff_));
 115   }
 116 }
 117
 118 namespace simgrid {
 119 namespace mc {
 120
 121 void CommunicationDeterminismChecker::deterministic_comm_pattern(int process, const PatternCommunication* comm,
 122                                                                  int backtracking)
 123 {
 124   if (not backtracking) {
 125     PatternCommunicationList& list      = initial_communications_pattern[process];
 126     e_mc_comm_pattern_difference_t diff = compare_comm_pattern(list.list[list.index_comm].get(), comm);
 127
 128     if (diff != NONE_DIFF) {
 129       if (comm->type == PatternCommunicationType::send) {
 130         this->send_deterministic = false;
 131         if (this->send_diff != nullptr)
 132           xbt_free(this->send_diff);
 133         this->send_diff = print_determinism_result(diff, process, comm, list.index_comm + 1);
 134       } else {
 135         this->recv_deterministic = false;
 136         if (this->recv_diff != nullptr)
 137           xbt_free(this->recv_diff);
 138         this->recv_diff = print_determinism_result(diff, process, comm, list.index_comm + 1);
 139       }
 140       if (_sg_mc_send_determinism && not this->send_deterministic) {
 141         XBT_INFO("*********************************************************");
 142         XBT_INFO("***** Non-send-deterministic communications pattern *****");
 143         XBT_INFO("*********************************************************");
 144         XBT_INFO("%s", this->send_diff);
 145         xbt_free(this->send_diff);
 146         this->send_diff = nullptr;
 147         mc::session->log_state();
 148         mc_model_checker->exit(SIMGRID_MC_EXIT_NON_DETERMINISM);
 149       } else if (_sg_mc_comms_determinism && (not this->send_deterministic && not this->recv_deterministic)) {
 150         XBT_INFO("****************************************************");
 151         XBT_INFO("***** Non-deterministic communications pattern *****");
 152         XBT_INFO("****************************************************");
 153         if (this->send_diff) {
 154           XBT_INFO("%s", this->send_diff);
 155           xbt_free(this->send_diff);
 156           this->send_diff = nullptr;
 157         }
 158         if (this->recv_diff) {
 159           XBT_INFO("%s", this->recv_diff);
 160           xbt_free(this->recv_diff);
 161           this->recv_diff = nullptr;
 162         }
 163         mc::session->log_state();
 164         mc_model_checker->exit(SIMGRID_MC_EXIT_NON_DETERMINISM);
 165       }
 166     }
 167   }
 168 }
 169
 170 /********** Non Static functions ***********/
 171
 172 void CommunicationDeterminismChecker::get_comm_pattern(smx_simcall_t request, e_mc_call_type_t call_type,
 173                                                        int backtracking)
 174 {
 175   const smx_actor_t issuer = MC_smx_simcall_get_issuer(request);
 176   const mc::PatternCommunicationList& initial_pattern          = initial_communications_pattern[issuer->get_pid()];
 177   const std::vector<PatternCommunication*>& incomplete_pattern = incomplete_communications_pattern[issuer->get_pid()];
 178
 179   std::unique_ptr<PatternCommunication> pattern(new PatternCommunication());
 180   pattern->index = initial_pattern.index_comm + incomplete_pattern.size();
 181
 182   if (call_type == MC_CALL_TYPE_SEND) {
 183     /* Create comm pattern */
 184     pattern->type      = PatternCommunicationType::send;
 185     pattern->comm_addr = static_cast<kernel::activity::CommImpl*>(simcall_comm_isend__getraw__result(request));
 186
 187     Remote<kernel::activity::CommImpl> temp_synchro;
 188     mc_model_checker->get_remote_simulation().read(temp_synchro, remote(pattern->comm_addr));
 189     const kernel::activity::CommImpl* synchro = temp_synchro.get_buffer();
 190
 191     char* remote_name = mc_model_checker->get_remote_simulation().read<char*>(RemotePtr<char*>(
 192         (uint64_t)(synchro->get_mailbox() ? &synchro->get_mailbox()->name_ : &synchro->mbox_cpy->name_)));
 193     pattern->rdv      = mc_model_checker->get_remote_simulation().read_string(RemotePtr<char>(remote_name));
 194     pattern->src_proc =
 195         mc_model_checker->get_remote_simulation().resolve_actor(mc::remote(synchro->src_actor_.get()))->get_pid();
 196     pattern->src_host = MC_smx_actor_get_host_name(issuer);
 197
 198 #if HAVE_SMPI
 199     simgrid::smpi::Request mpi_request;
 200     mc_model_checker->get_remote_simulation().read(
 201         &mpi_request, remote(static_cast<smpi::Request*>(simcall_comm_isend__get__data(request))));
 202     pattern->tag = mpi_request.tag();
 203 #endif
 204
 205     if (synchro->src_buff_ != nullptr) {
 206       pattern->data.resize(synchro->src_buff_size_);
 207       mc_model_checker->get_remote_simulation().read_bytes(pattern->data.data(), pattern->data.size(),
 208                                                            remote(synchro->src_buff_));
 209     }
 210 #if HAVE_SMPI
 211     if(mpi_request.detached()){
 212       if (this->initial_communications_pattern_done) {
 213         /* Evaluate comm determinism */
 214         this->deterministic_comm_pattern(pattern->src_proc, pattern.get(), backtracking);
 215         initial_communications_pattern[pattern->src_proc].index_comm++;
 216       } else {
 217         /* Store comm pattern */
 218         initial_communications_pattern[pattern->src_proc].list.push_back(std::move(pattern));
 219       }
 220       return;
 221     }
 222 #endif
 223   } else if (call_type == MC_CALL_TYPE_RECV) {
 224     pattern->type      = PatternCommunicationType::receive;
 225     pattern->comm_addr = static_cast<kernel::activity::CommImpl*>(simcall_comm_irecv__getraw__result(request));
 226
 227 #if HAVE_SMPI
 228     smpi::Request mpi_request;
 229     mc_model_checker->get_remote_simulation().read(
 230         &mpi_request, remote(static_cast<smpi::Request*>(simcall_comm_irecv__get__data(request))));
 231     pattern->tag = mpi_request.tag();
 232 #endif
 233
 234     Remote<kernel::activity::CommImpl> temp_comm;
 235     mc_model_checker->get_remote_simulation().read(temp_comm, remote(pattern->comm_addr));
 236     const kernel::activity::CommImpl* comm = temp_comm.get_buffer();
 237
 238     char* remote_name;
 239     mc_model_checker->get_remote_simulation().read(
 240         &remote_name, remote(comm->get_mailbox() ? &xbt::string::to_string_data(comm->get_mailbox()->name_).data
 241                                                  : &xbt::string::to_string_data(comm->mbox_cpy->name_).data));
 242     pattern->rdv = mc_model_checker->get_remote_simulation().read_string(RemotePtr<char>(remote_name));
 243     pattern->dst_proc =
 244         mc_model_checker->get_remote_simulation().resolve_actor(mc::remote(comm->dst_actor_.get()))->get_pid();
 245     pattern->dst_host = MC_smx_actor_get_host_name(issuer);
 246   } else
 247     xbt_die("Unexpected call_type %i", (int) call_type);
 248
 249   XBT_DEBUG("Insert incomplete comm pattern %p for process %ld", pattern.get(), issuer->get_pid());
 250   incomplete_communications_pattern[issuer->get_pid()].push_back(pattern.release());
 251 }
 252
 253 void CommunicationDeterminismChecker::complete_comm_pattern(RemotePtr<kernel::activity::CommImpl> comm_addr,
 254                                                             unsigned int issuer, int backtracking)
 255 {
 256   /* Complete comm pattern */
 257   std::vector<PatternCommunication*>& incomplete_pattern = incomplete_communications_pattern[issuer];
 258   auto current_comm_pattern =
 259       std::find_if(begin(incomplete_pattern), end(incomplete_pattern),
 260                    [&comm_addr](const PatternCommunication* comm) { return remote(comm->comm_addr) == comm_addr; });
 261   if (current_comm_pattern == std::end(incomplete_pattern))
 262     xbt_die("Corresponding communication not found!");
 263
 264   update_comm_pattern(*current_comm_pattern, comm_addr);
 265   std::unique_ptr<PatternCommunication> comm_pattern(*current_comm_pattern);
 266   XBT_DEBUG("Remove incomplete comm pattern for process %u at cursor %zd", issuer,
 267             std::distance(begin(incomplete_pattern), current_comm_pattern));
 268   incomplete_pattern.erase(current_comm_pattern);
 269
 270   if (this->initial_communications_pattern_done) {
 271     /* Evaluate comm determinism */
 272     this->deterministic_comm_pattern(issuer, comm_pattern.get(), backtracking);
 273     initial_communications_pattern[issuer].index_comm++;
 274   } else {
 275     /* Store comm pattern */
 276     initial_communications_pattern[issuer].list.push_back(std::move(comm_pattern));
 277   }
 278 }
 279
 280 CommunicationDeterminismChecker::CommunicationDeterminismChecker(Session& s) : Checker(s)
 281 {
 282 }
 283
 284 CommunicationDeterminismChecker::~CommunicationDeterminismChecker() = default;
 285
 286 RecordTrace CommunicationDeterminismChecker::get_record_trace() // override
 287 {
 288   RecordTrace res;
 289   for (auto const& state : stack_)
 290     res.push_back(state->get_transition());
 291   return res;
 292 }
 293
 294 std::vector<std::string> CommunicationDeterminismChecker::get_textual_trace() // override
 295 {
 296   std::vector<std::string> trace;
 297   for (auto const& state : stack_) {
 298     smx_simcall_t req = &state->executed_req_;
 299     if (req)
 300       trace.push_back(request_to_string(req, state->transition_.argument_, RequestType::executed));
 301   }
 302   return trace;
 303 }
 304
 305 void CommunicationDeterminismChecker::log_state() // override
 306 {
 307   if (_sg_mc_comms_determinism) {
 308     if (this->send_deterministic && not this->recv_deterministic) {
 309       XBT_INFO("*******************************************************");
 310       XBT_INFO("**** Only-send-deterministic communication pattern ****");
 311       XBT_INFO("*******************************************************");
 312       XBT_INFO("%s", this->recv_diff);
 313     }
 314     if (not this->send_deterministic && this->recv_deterministic) {
 315       XBT_INFO("*******************************************************");
 316       XBT_INFO("**** Only-recv-deterministic communication pattern ****");
 317       XBT_INFO("*******************************************************");
 318       XBT_INFO("%s", this->send_diff);
 319     }
 320   }
 321   XBT_INFO("Expanded states = %lu", expanded_states_count_);
 322   XBT_INFO("Visited states = %lu", mc_model_checker->visited_states);
 323   XBT_INFO("Executed transitions = %lu", mc_model_checker->executed_transitions);
 324   XBT_INFO("Send-deterministic : %s", this->send_deterministic ? "Yes" : "No");
 325   if (_sg_mc_comms_determinism)
 326     XBT_INFO("Recv-deterministic : %s", this->recv_deterministic ? "Yes" : "No");
 327 }
 328
 329 void CommunicationDeterminismChecker::prepare()
 330 {
 331   const int maxpid = MC_smx_get_maxpid();
 332
 333   initial_communications_pattern.resize(maxpid);
 334   incomplete_communications_pattern.resize(maxpid);
 335
 336   std::unique_ptr<State> initial_state(new State(++expanded_states_count_));
 337
 338   XBT_DEBUG("********* Start communication determinism verification *********");
 339
 340   /* Get an enabled actor and insert it in the interleave set of the initial state */
 341   for (auto& actor : mc_model_checker->get_remote_simulation().actors())
 342     if (mc::actor_is_enabled(actor.copy.get_buffer()))
 343       initial_state->add_interleaving_set(actor.copy.get_buffer());
 344
 345   stack_.push_back(std::move(initial_state));
 346 }
 347
 348 static inline bool all_communications_are_finished()
 349 {
 350   for (size_t current_actor = 1; current_actor < MC_smx_get_maxpid(); current_actor++) {
 351     if (not incomplete_communications_pattern[current_actor].empty()) {
 352       XBT_DEBUG("Some communications are not finished, cannot stop the exploration! State not visited.");
 353       return false;
 354     }
 355   }
 356   return true;
 357 }
 358
 359 void CommunicationDeterminismChecker::restoreState()
 360 {
 361   /* Intermediate backtracking */
 362   State* last_state = stack_.back().get();
 363   if (last_state->system_state_) {
 364     last_state->system_state_->restore(&mc_model_checker->get_remote_simulation());
 365     MC_restore_communications_pattern(last_state);
 366     return;
 367   }
 368
 369   /* Restore the initial state */
 370   mc::session->restore_initial_state();
 371
 372   unsigned n = MC_smx_get_maxpid();
 373   assert(n == incomplete_communications_pattern.size());
 374   assert(n == initial_communications_pattern.size());
 375   for (unsigned j=0; j < n ; j++) {
 376     incomplete_communications_pattern[j].clear();
 377     initial_communications_pattern[j].index_comm = 0;
 378   }
 379
 380   /* Traverse the stack from the state at position start and re-execute the transitions */
 381   for (std::unique_ptr<simgrid::mc::State> const& state : stack_) {
 382     if (state == stack_.back())
 383       break;
 384
 385     int req_num             = state->transition_.argument_;
 386     const s_smx_simcall* saved_req = &state->executed_req_;
 387     xbt_assert(saved_req);
 388
 389     /* because we got a copy of the executed request, we have to fetch the
 390        real one, pointed by the request field of the issuer process */
 391
 392     const smx_actor_t issuer = MC_smx_simcall_get_issuer(saved_req);
 393     smx_simcall_t req        = &issuer->simcall_;
 394
 395     /* TODO : handle test and testany simcalls */
 396     e_mc_call_type_t call = MC_get_call_type(req);
 397     mc_model_checker->handle_simcall(state->transition_);
 398     MC_handle_comm_pattern(call, req, req_num, 1);
 399     mc_model_checker->wait_for_requests();
 400
 401     /* Update statistics */
 402     mc_model_checker->visited_states++;
 403     mc_model_checker->executed_transitions++;
 404   }
 405 }
 406
 407 void CommunicationDeterminismChecker::real_run()
 408 {
 409   std::unique_ptr<VisitedState> visited_state = nullptr;
 410   smx_simcall_t req = nullptr;
 411
 412   while (not stack_.empty()) {
 413     /* Get current state */
 414     State* cur_state = stack_.back().get();
 415
 416     XBT_DEBUG("**************************************************");
 417     XBT_DEBUG("Exploration depth = %zu (state = %d, interleaved processes = %zu)", stack_.size(), cur_state->num_,
 418               cur_state->interleave_size());
 419
 420     /* Update statistics */
 421     mc_model_checker->visited_states++;
 422
 423     if (stack_.size() <= (std::size_t)_sg_mc_max_depth)
 424       req = MC_state_choose_request(cur_state);
 425     else
 426       req = nullptr;
 427
 428     if (req != nullptr && visited_state == nullptr) {
 429       int req_num = cur_state->transition_.argument_;
 430
 431       XBT_DEBUG("Execute: %s", request_to_string(req, req_num, RequestType::simix).c_str());
 432
 433       std::string req_str;
 434       if (dot_output != nullptr)
 435         req_str = request_get_dot_output(req, req_num);
 436
 437       mc_model_checker->executed_transitions++;
 438
 439       /* TODO : handle test and testany simcalls */
 440       e_mc_call_type_t call = MC_CALL_TYPE_NONE;
 441       if (_sg_mc_comms_determinism || _sg_mc_send_determinism)
 442         call = MC_get_call_type(req);
 443
 444       /* Answer the request */
 445       mc_model_checker->handle_simcall(cur_state->transition_);
 446       /* After this call req is no longer useful */
 447
 448       MC_handle_comm_pattern(call, req, req_num, 0);
 449
 450       /* Wait for requests (schedules processes) */
 451       mc_model_checker->wait_for_requests();
 452
 453       /* Create the new expanded state */
 454       std::unique_ptr<State> next_state(new State(++expanded_states_count_));
 455
 456       /* If comm determinism verification, we cannot stop the exploration if some communications are not finished (at
 457        * least, data are transferred). These communications  are incomplete and they cannot be analyzed and compared
 458        * with the initial pattern. */
 459       bool compare_snapshots = this->initial_communications_pattern_done && all_communications_are_finished();
 460
 461       if (_sg_mc_max_visited_states != 0)
 462         visited_state = visited_states_.addVisitedState(expanded_states_count_, next_state.get(), compare_snapshots);
 463       else
 464         visited_state = nullptr;
 465
 466       if (visited_state == nullptr) {
 467         /* Get enabled actors and insert them in the interleave set of the next state */
 468         for (auto& actor : mc_model_checker->get_remote_simulation().actors())
 469           if (simgrid::mc::actor_is_enabled(actor.copy.get_buffer()))
 470             next_state->add_interleaving_set(actor.copy.get_buffer());
 471
 472         if (dot_output != nullptr)
 473           fprintf(dot_output, "\"%d\" -> \"%d\" [%s];\n", cur_state->num_, next_state->num_, req_str.c_str());
 474
 475       } else if (dot_output != nullptr)
 476         fprintf(dot_output, "\"%d\" -> \"%d\" [%s];\n", cur_state->num_,
 477                 visited_state->original_num == -1 ? visited_state->num : visited_state->original_num, req_str.c_str());
 478
 479       stack_.push_back(std::move(next_state));
 480     } else {
 481       if (stack_.size() > (std::size_t) _sg_mc_max_depth)
 482         XBT_WARN("/!\\ Max depth reached! /!\\ ");
 483       else if (visited_state != nullptr)
 484         XBT_DEBUG("State already visited (equal to state %d), exploration stopped on this path.",
 485             visited_state->original_num == -1 ? visited_state->num : visited_state->original_num);
 486       else
 487         XBT_DEBUG("There are no more processes to interleave. (depth %zu)", stack_.size());
 488
 489       this->initial_communications_pattern_done = true;
 490
 491       /* Trash the current state, no longer needed */
 492       XBT_DEBUG("Delete state %d at depth %zu", cur_state->num_, stack_.size());
 493       stack_.pop_back();
 494
 495       visited_state = nullptr;
 496
 497       /* Check for deadlocks */
 498       if (mc_model_checker->checkDeadlock()) {
 499         MC_show_deadlock();
 500         throw simgrid::mc::DeadlockError();
 501       }
 502
 503       while (not stack_.empty()) {
 504         std::unique_ptr<State> state(std::move(stack_.back()));
 505         stack_.pop_back();
 506         if (state->interleave_size() && stack_.size() < (std::size_t)_sg_mc_max_depth) {
 507           /* We found a back-tracking point, let's loop */
 508           XBT_DEBUG("Back-tracking to state %d at depth %zu", state->num_, stack_.size() + 1);
 509           stack_.push_back(std::move(state));
 510
 511           this->restoreState();
 512
 513           XBT_DEBUG("Back-tracking to state %d at depth %zu done", stack_.back()->num_, stack_.size());
 514
 515           break;
 516         } else {
 517           XBT_DEBUG("Delete state %d at depth %zu", state->num_, stack_.size() + 1);
 518         }
 519       }
 520     }
 521   }
 522
 523   mc::session->log_state();
 524 }
 525
 526 void CommunicationDeterminismChecker::run()
 527 {
 528   XBT_INFO("Check communication determinism");
 529   mc::session->initialize();
 530
 531   this->prepare();
 532   this->real_run();
 533 }
 534
 535 Checker* createCommunicationDeterminismChecker(Session& s)
 536 {
 537   return new CommunicationDeterminismChecker(s);
 538 }
 539
 540 } // namespace mc
 541 } // namespace simgrid