src/s4u/s4u_Comm.cpp

   1 /* Copyright (c) 2006-2023. 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 <cmath>
   7 #include <simgrid/Exception.hpp>
   8 #include <simgrid/comm.h>
   9 #include <simgrid/s4u/Comm.hpp>
  10 #include <simgrid/s4u/Engine.hpp>
  11 #include <simgrid/s4u/Mailbox.hpp>
  12
  13 #include "src/kernel/activity/CommImpl.hpp"
  14 #include "src/kernel/actor/ActorImpl.hpp"
  15 #include "src/kernel/actor/SimcallObserver.hpp"
  16 #include "src/mc/mc.h"
  17 #include "src/mc/mc_replay.hpp"
  18
  19 XBT_LOG_NEW_DEFAULT_SUBCATEGORY(s4u_comm, s4u_activity, "S4U asynchronous communications");
  20
  21 namespace simgrid::s4u {
  22 xbt::signal<void(Comm const&)> Comm::on_send;
  23 xbt::signal<void(Comm const&)> Comm::on_recv;
  24
  25 CommPtr Comm::set_copy_data_callback(const std::function<void(kernel::activity::CommImpl*, void*, size_t)>& callback)
  26 {
  27   copy_data_function_ = callback;
  28   return this;
  29 }
  30
  31 void Comm::copy_buffer_callback(kernel::activity::CommImpl* comm, void* buff,
  32                                 size_t buff_size) // XBT_ATTRIB_DEPRECATED_v337
  33 {
  34   XBT_DEBUG("Copy the data over");
  35   memcpy(comm->dst_buff_, buff, buff_size);
  36   if (comm->is_detached()) { // if this is a detached send, the source buffer was duplicated by SMPI sender to make the
  37                              // original buffer available to the application ASAP
  38     xbt_free(buff);
  39     comm->src_buff_ = nullptr;
  40   }
  41 }
  42
  43 void Comm::copy_pointer_callback(kernel::activity::CommImpl* comm, void* buff,
  44                                  size_t buff_size) // XBT_ATTRIB_DEPRECATED_v337
  45 {
  46   xbt_assert((buff_size == sizeof(void*)), "Cannot copy %zu bytes: must be sizeof(void*)", buff_size);
  47   *(void**)(comm->dst_buff_) = buff;
  48 }
  49
  50 Comm::~Comm()
  51 {
  52   if (state_ == State::STARTED && not detached_ &&
  53       (pimpl_ == nullptr || pimpl_->get_state() == kernel::activity::State::RUNNING)) {
  54     XBT_INFO("Comm %p freed before its completion. Did you forget to detach it? (state: %s)", this, get_state_str());
  55     if (pimpl_ != nullptr)
  56       XBT_INFO("pimpl_->state: %s", pimpl_->get_state_str());
  57     else
  58       XBT_INFO("pimpl_ is null");
  59     xbt_backtrace_display_current();
  60   }
  61 }
  62
  63 void Comm::send(kernel::actor::ActorImpl* sender, const Mailbox* mbox, double task_size, double rate, void* src_buff,
  64                 size_t src_buff_size,
  65                 const std::function<bool(void*, void*, simgrid::kernel::activity::CommImpl*)>& match_fun,
  66                 const std::function<void(simgrid::kernel::activity::CommImpl*, void*, size_t)>& copy_data_fun,
  67                 void* data, double timeout)
  68 {
  69   /* checking for infinite values */
  70   xbt_assert(std::isfinite(task_size), "task_size is not finite!");
  71   xbt_assert(std::isfinite(rate), "rate is not finite!");
  72   xbt_assert(std::isfinite(timeout), "timeout is not finite!");
  73
  74   xbt_assert(mbox, "No rendez-vous point defined for send");
  75
  76   if (MC_is_active() || MC_record_replay_is_active()) {
  77     /* the model-checker wants two separate simcalls, and wants comm to be nullptr during the simcall */
  78     simgrid::kernel::activity::ActivityImplPtr comm = nullptr;
  79
  80     simgrid::kernel::actor::CommIsendSimcall send_observer{
  81         sender,  mbox->get_impl(), task_size, rate, static_cast<unsigned char*>(src_buff), src_buff_size, match_fun,
  82         nullptr, copy_data_fun,    data,      false};
  83     comm = simgrid::kernel::actor::simcall_answered(
  84         [&send_observer] { return simgrid::kernel::activity::CommImpl::isend(&send_observer); }, &send_observer);
  85
  86     if (simgrid::kernel::actor::ActivityWaitSimcall wait_observer{sender, comm.get(), timeout};
  87         simgrid::kernel::actor::simcall_blocking(
  88             [&wait_observer] {
  89               wait_observer.get_activity()->wait_for(wait_observer.get_issuer(), wait_observer.get_timeout());
  90             },
  91             &wait_observer)) {
  92       throw simgrid::TimeoutException(XBT_THROW_POINT, "Timeouted");
  93     }
  94     comm = nullptr;
  95   } else {
  96     simgrid::kernel::actor::CommIsendSimcall observer(sender, mbox->get_impl(), task_size, rate,
  97                                                       static_cast<unsigned char*>(src_buff), src_buff_size, match_fun,
  98                                                       nullptr, copy_data_fun, data, false);
  99     simgrid::kernel::actor::simcall_blocking([&observer, timeout] {
 100       simgrid::kernel::activity::ActivityImplPtr comm = simgrid::kernel::activity::CommImpl::isend(&observer);
 101       comm->wait_for(observer.get_issuer(), timeout);
 102     });
 103   }
 104 }
 105
 106 void Comm::recv(kernel::actor::ActorImpl* receiver, const Mailbox* mbox, void* dst_buff, size_t* dst_buff_size,
 107                 const std::function<bool(void*, void*, simgrid::kernel::activity::CommImpl*)>& match_fun,
 108                 const std::function<void(simgrid::kernel::activity::CommImpl*, void*, size_t)>& copy_data_fun,
 109                 void* data, double timeout, double rate)
 110 {
 111   xbt_assert(std::isfinite(timeout), "timeout is not finite!");
 112   xbt_assert(mbox, "No rendez-vous point defined for recv");
 113
 114   if (MC_is_active() || MC_record_replay_is_active()) {
 115     /* the model-checker wants two separate simcalls, and wants comm to be nullptr during the simcall */
 116     simgrid::kernel::activity::ActivityImplPtr comm = nullptr;
 117
 118     simgrid::kernel::actor::CommIrecvSimcall observer{receiver,
 119                                                       mbox->get_impl(),
 120                                                       static_cast<unsigned char*>(dst_buff),
 121                                                       dst_buff_size,
 122                                                       match_fun,
 123                                                       copy_data_fun,
 124                                                       data,
 125                                                       rate};
 126     comm = simgrid::kernel::actor::simcall_answered(
 127         [&observer] { return simgrid::kernel::activity::CommImpl::irecv(&observer); }, &observer);
 128
 129     if (simgrid::kernel::actor::ActivityWaitSimcall wait_observer{receiver, comm.get(), timeout};
 130         simgrid::kernel::actor::simcall_blocking(
 131             [&wait_observer] {
 132               wait_observer.get_activity()->wait_for(wait_observer.get_issuer(), wait_observer.get_timeout());
 133             },
 134             &wait_observer)) {
 135       throw simgrid::TimeoutException(XBT_THROW_POINT, "Timeouted");
 136     }
 137     comm = nullptr;
 138   } else {
 139     simgrid::kernel::actor::CommIrecvSimcall observer(receiver, mbox->get_impl(), static_cast<unsigned char*>(dst_buff),
 140                                                       dst_buff_size, match_fun, copy_data_fun, data, rate);
 141     simgrid::kernel::actor::simcall_blocking([&observer, timeout] {
 142       simgrid::kernel::activity::ActivityImplPtr comm = simgrid::kernel::activity::CommImpl::irecv(&observer);
 143       comm->wait_for(observer.get_issuer(), timeout);
 144     });
 145   }
 146 }
 147
 148 CommPtr Comm::sendto_init()
 149 {
 150   CommPtr res(new Comm());
 151   res->pimpl_ = kernel::activity::CommImplPtr(new kernel::activity::CommImpl());
 152   boost::static_pointer_cast<kernel::activity::CommImpl>(res->pimpl_)->detach();
 153   res->sender_ = kernel::actor::ActorImpl::self();
 154   return res;
 155 }
 156
 157 CommPtr Comm::sendto_init(Host* from, Host* to)
 158 {
 159   auto res = Comm::sendto_init()->set_source(from)->set_destination(to);
 160   res->set_state(State::STARTING);
 161   return res;
 162 }
 163
 164 CommPtr Comm::sendto_async(Host* from, Host* to, uint64_t simulated_size_in_bytes)
 165 {
 166   return Comm::sendto_init()->set_payload_size(simulated_size_in_bytes)->set_source(from)->set_destination(to);
 167 }
 168
 169 void Comm::sendto(Host* from, Host* to, uint64_t simulated_size_in_bytes)
 170 {
 171   sendto_async(from, to, simulated_size_in_bytes)->wait();
 172 }
 173
 174 CommPtr Comm::set_source(Host* from)
 175 {
 176   xbt_assert(state_ == State::INITED || state_ == State::STARTING,
 177              "Cannot change the source of a Comm once it's started (state: %s)", to_c_str(state_));
 178   boost::static_pointer_cast<kernel::activity::CommImpl>(pimpl_)->set_source(from);
 179   // Setting 'source' may allow to start the activity, let's try
 180   if (state_ == State::STARTING && remains_ <= 0)
 181     XBT_DEBUG("This communication has a payload size of 0 byte. It cannot start yet");
 182   else
 183     start();
 184
 185   return this;
 186 }
 187 Host* Comm::get_source() const
 188 {
 189   return pimpl_ ? boost::static_pointer_cast<kernel::activity::CommImpl>(pimpl_)->get_source() : nullptr;
 190 }
 191
 192 CommPtr Comm::set_destination(Host* to)
 193 {
 194   xbt_assert(state_ == State::INITED || state_ == State::STARTING,
 195              "Cannot change the destination of a Comm once it's started (state: %s)", to_c_str(state_));
 196   boost::static_pointer_cast<kernel::activity::CommImpl>(pimpl_)->set_destination(to);
 197   // Setting 'destination' may allow to start the activity, let's try
 198   if (state_ == State::STARTING && remains_ <= 0)
 199     XBT_DEBUG("This communication has a payload size of 0 byte. It cannot start yet");
 200   else
 201     start();
 202
 203   return this;
 204 }
 205
 206 Host* Comm::get_destination() const
 207 {
 208   return pimpl_ ? boost::static_pointer_cast<kernel::activity::CommImpl>(pimpl_)->get_destination() : nullptr;
 209 }
 210
 211 CommPtr Comm::set_rate(double rate)
 212 {
 213   xbt_assert(state_ == State::INITED, "You cannot use %s() once your communication started (not implemented)",
 214              __FUNCTION__);
 215   rate_ = rate;
 216   return this;
 217 }
 218
 219 CommPtr Comm::set_mailbox(Mailbox* mailbox)
 220 {
 221   xbt_assert(state_ == State::INITED, "You cannot use %s() once your communication started (not implemented)",
 222              __FUNCTION__);
 223   mailbox_ = mailbox;
 224   return this;
 225 }
 226
 227 CommPtr Comm::set_src_data(void* buff)
 228 {
 229   xbt_assert(state_ == State::INITED, "You cannot use %s() once your communication started (not implemented)",
 230              __FUNCTION__);
 231   xbt_assert(dst_buff_ == nullptr, "Cannot set the src and dst buffers at the same time");
 232   src_buff_ = buff;
 233   return this;
 234 }
 235
 236 CommPtr Comm::set_src_data_size(size_t size)
 237 {
 238   xbt_assert(state_ == State::INITED, "You cannot use %s() once your communication started (not implemented)",
 239              __FUNCTION__);
 240   src_buff_size_ = size;
 241   return this;
 242 }
 243
 244 CommPtr Comm::set_src_data(void* buff, size_t size)
 245 {
 246   xbt_assert(state_ == State::INITED, "You cannot use %s() once your communication started (not implemented)",
 247              __FUNCTION__);
 248
 249   xbt_assert(dst_buff_ == nullptr, "Cannot set the src and dst buffers at the same time");
 250   src_buff_      = buff;
 251   src_buff_size_ = size;
 252   return this;
 253 }
 254
 255 CommPtr Comm::set_dst_data(void** buff)
 256 {
 257   xbt_assert(state_ == State::INITED, "You cannot use %s() once your communication started (not implemented)",
 258              __FUNCTION__);
 259   xbt_assert(src_buff_ == nullptr, "Cannot set the src and dst buffers at the same time");
 260   dst_buff_ = buff;
 261   return this;
 262 }
 263
 264 CommPtr Comm::set_dst_data(void** buff, size_t size)
 265 {
 266   xbt_assert(state_ == State::INITED, "You cannot use %s() once your communication started (not implemented)",
 267              __FUNCTION__);
 268
 269   xbt_assert(src_buff_ == nullptr, "Cannot set the src and dst buffers at the same time");
 270   dst_buff_      = buff;
 271   dst_buff_size_ = size;
 272   return this;
 273 }
 274
 275 CommPtr Comm::set_payload_size(uint64_t bytes)
 276 {
 277   set_remaining(bytes);
 278   if (pimpl_) {
 279     boost::static_pointer_cast<kernel::activity::CommImpl>(pimpl_)->set_size(bytes);
 280   }
 281   return this;
 282 }
 283
 284 Actor* Comm::get_sender() const
 285 {
 286   kernel::actor::ActorImplPtr sender = nullptr;
 287   if (pimpl_)
 288     sender = boost::static_pointer_cast<kernel::activity::CommImpl>(pimpl_)->src_actor_;
 289   return sender ? sender->get_ciface() : nullptr;
 290 }
 291
 292 Actor* Comm::get_receiver() const
 293 {
 294   kernel::actor::ActorImplPtr receiver = nullptr;
 295   if (pimpl_)
 296     receiver = boost::static_pointer_cast<kernel::activity::CommImpl>(pimpl_)->dst_actor_;
 297   return receiver ? receiver->get_ciface() : nullptr;
 298 }
 299
 300 bool Comm::is_assigned() const
 301 {
 302   return (pimpl_ && boost::static_pointer_cast<kernel::activity::CommImpl>(pimpl_)->is_assigned()) ||
 303          mailbox_ != nullptr;
 304 }
 305
 306 Comm* Comm::do_start()
 307 {
 308   xbt_assert(get_state() == State::INITED || get_state() == State::STARTING,
 309              "You cannot use %s() once your communication started (not implemented)", __FUNCTION__);
 310   if (get_source() != nullptr || get_destination() != nullptr) {
 311     xbt_assert(is_assigned(), "When either from_ or to_ is specified, both must be.");
 312     xbt_assert(src_buff_ == nullptr && dst_buff_ == nullptr,
 313                "Direct host-to-host communications cannot carry any data.");
 314     XBT_DEBUG("host-to-host Comm. Pimpl already created and set, just start it.");
 315     on_start(*this);
 316     on_this_start(*this);
 317     kernel::actor::simcall_answered([this] {
 318       pimpl_->set_state(kernel::activity::State::READY);
 319       boost::static_pointer_cast<kernel::activity::CommImpl>(pimpl_)->start();
 320     });
 321   } else if (src_buff_ != nullptr) { // Sender side
 322     on_send(*this);
 323     on_this_send(*this);
 324     kernel::actor::CommIsendSimcall observer{sender_,
 325                                              mailbox_->get_impl(),
 326                                              remains_,
 327                                              rate_,
 328                                              static_cast<unsigned char*>(src_buff_),
 329                                              src_buff_size_,
 330                                              match_fun_,
 331                                              clean_fun_,
 332                                              copy_data_function_,
 333                                              get_data<void>(),
 334                                              detached_};
 335     pimpl_ = kernel::actor::simcall_answered([&observer] { return kernel::activity::CommImpl::isend(&observer); },
 336                                              &observer);
 337   } else if (dst_buff_ != nullptr) { // Receiver side
 338     xbt_assert(not detached_, "Receive cannot be detached");
 339     on_recv(*this);
 340     on_this_recv(*this);
 341     kernel::actor::CommIrecvSimcall observer{receiver_,
 342                                              mailbox_->get_impl(),
 343                                              static_cast<unsigned char*>(dst_buff_),
 344                                              &dst_buff_size_,
 345                                              match_fun_,
 346                                              copy_data_function_,
 347                                              get_data<void>(),
 348                                              rate_};
 349     pimpl_ = kernel::actor::simcall_answered([&observer] { return kernel::activity::CommImpl::irecv(&observer); },
 350                                              &observer);
 351   } else {
 352     xbt_die("Cannot start a communication before specifying whether we are the sender or the receiver");
 353   }
 354
 355   if (suspended_)
 356     pimpl_->suspend();
 357
 358   if (not detached_) {
 359     pimpl_->set_iface(this);
 360     pimpl_->set_actor(sender_);
 361     // Only throw the signal when both sides are here and the status is READY
 362     if (pimpl_->get_state() != kernel::activity::State::WAITING) {
 363       on_start(*this);
 364       on_this_start(*this);
 365     }
 366   }
 367
 368   state_ = State::STARTED;
 369   return this;
 370 }
 371
 372 Comm* Comm::detach()
 373 {
 374   xbt_assert(state_ == State::INITED || state_ == State::STARTING,
 375              "You cannot use %s() once your communication is %s (not implemented)", __FUNCTION__, get_state_str());
 376   xbt_assert(dst_buff_ == nullptr && dst_buff_size_ == 0, "You can only detach sends, not recvs");
 377   detached_ = true;
 378   start();
 379   return this;
 380 }
 381
 382 ssize_t Comm::test_any(const std::vector<CommPtr>& comms)
 383 {
 384   std::vector<ActivityPtr> activities;
 385   for (const auto& comm : comms)
 386     activities.push_back(boost::dynamic_pointer_cast<Activity>(comm));
 387   return Activity::test_any(activities);
 388 }
 389
 390 /** @brief Block the calling actor until the communication is finished, or until timeout
 391  *
 392  * On timeout, an exception is thrown and the communication is invalidated.
 393  *
 394  * @param timeout the amount of seconds to wait for the comm termination.
 395  *                Negative values denote infinite wait times. 0 as a timeout returns immediately. */
 396 Comm* Comm::wait_for(double timeout)
 397 {
 398   XBT_DEBUG("Calling Comm::wait_for with state %s", get_state_str());
 399   kernel::actor::ActorImpl* issuer = nullptr;
 400   switch (state_) {
 401     case State::FINISHED:
 402       break;
 403     case State::FAILED:
 404       throw NetworkFailureException(XBT_THROW_POINT, "Cannot wait for a failed communication");
 405     case State::INITED:
 406     case State::STARTING: // It's not started yet. Do it in one simcall if it's a regular communication
 407       if (get_source() != nullptr || get_destination() != nullptr) {
 408         return start()->wait_for(timeout); // In the case of host2host comm, do it in two simcalls
 409       } else if (src_buff_ != nullptr) {
 410         on_send(*this);
 411         on_this_send(*this);
 412         send(sender_, mailbox_, remains_, rate_, src_buff_, src_buff_size_, match_fun_, copy_data_function_,
 413              get_data<void>(), timeout);
 414
 415       } else { // Receiver
 416         on_recv(*this);
 417         on_this_recv(*this);
 418         recv(receiver_, mailbox_, dst_buff_, &dst_buff_size_, match_fun_, copy_data_function_, get_data<void>(),
 419              timeout, rate_);
 420       }
 421       break;
 422     case State::STARTED:
 423       try {
 424         issuer = kernel::actor::ActorImpl::self();
 425         kernel::actor::ActivityWaitSimcall observer{issuer, pimpl_.get(), timeout};
 426         if (kernel::actor::simcall_blocking(
 427                 [&observer] { observer.get_activity()->wait_for(observer.get_issuer(), observer.get_timeout()); },
 428                 &observer)) {
 429           throw TimeoutException(XBT_THROW_POINT, "Timeouted");
 430         }
 431       } catch (const NetworkFailureException& e) {
 432         issuer->simcall_.observer_ = nullptr; // Comm failed on network failure, reset the observer to nullptr
 433         complete(State::FAILED);
 434         e.rethrow_nested(XBT_THROW_POINT, boost::core::demangle(typeid(e).name()) + " raised in kernel mode.");
 435       }
 436       break;
 437
 438     case State::CANCELED:
 439       throw CancelException(XBT_THROW_POINT, "Communication canceled");
 440
 441     default:
 442       THROW_IMPOSSIBLE;
 443   }
 444   complete(State::FINISHED);
 445   return this;
 446 }
 447
 448 ssize_t Comm::wait_any_for(const std::vector<CommPtr>& comms, double timeout)
 449 {
 450   std::vector<ActivityPtr> activities;
 451   for (const auto& comm : comms)
 452     activities.push_back(boost::dynamic_pointer_cast<Activity>(comm));
 453   ssize_t changed_pos;
 454   try {
 455     changed_pos = Activity::wait_any_for(activities, timeout);
 456   } catch (const NetworkFailureException& e) {
 457     changed_pos = -1;
 458     for (auto c : comms) {
 459       if (c->pimpl_->get_state() == kernel::activity::State::FAILED) {
 460         c->complete(State::FAILED);
 461       }
 462     }
 463     e.rethrow_nested(XBT_THROW_POINT, boost::core::demangle(typeid(e).name()) + " raised in kernel mode.");
 464   }
 465   return changed_pos;
 466 }
 467
 468 void Comm::wait_all(const std::vector<CommPtr>& comms)
 469 {
 470   // TODO: this should be a simcall or something
 471   for (auto& comm : comms)
 472     comm->wait();
 473 }
 474
 475 size_t Comm::wait_all_for(const std::vector<CommPtr>& comms, double timeout)
 476 {
 477   if (timeout < 0.0) {
 478     wait_all(comms);
 479     return comms.size();
 480   }
 481
 482   double deadline = Engine::get_clock() + timeout;
 483   std::vector<CommPtr> waited_comm(1, nullptr);
 484   for (size_t i = 0; i < comms.size(); i++) {
 485     double wait_timeout = std::max(0.0, deadline - Engine::get_clock());
 486     waited_comm[0]      = comms[i];
 487     // Using wait_any_for() here (and not wait_for) because we don't want comms to be invalidated on timeout
 488     if (wait_any_for(waited_comm, wait_timeout) == -1) {
 489       XBT_DEBUG("Timeout (%g): i = %zu", wait_timeout, i);
 490       return i;
 491     }
 492   }
 493   return comms.size();
 494 }
 495 } // namespace simgrid::s4u
 496 /* **************************** Public C interface *************************** */
 497 void sg_comm_detach(sg_comm_t comm, void (*clean_function)(void*))
 498 {
 499   comm->detach(clean_function);
 500   comm->unref();
 501 }
 502 void sg_comm_unref(sg_comm_t comm)
 503 {
 504   comm->unref();
 505 }
 506 int sg_comm_test(sg_comm_t comm)
 507 {
 508   bool finished = comm->test();
 509   if (finished)
 510     comm->unref();
 511   return finished;
 512 }
 513
 514 sg_error_t sg_comm_wait(sg_comm_t comm)
 515 {
 516   return sg_comm_wait_for(comm, -1);
 517 }
 518
 519 sg_error_t sg_comm_wait_for(sg_comm_t comm, double timeout)
 520 {
 521   sg_error_t status = SG_OK;
 522
 523   simgrid::s4u::CommPtr s4u_comm(comm, false);
 524   try {
 525     s4u_comm->wait_for(timeout);
 526   } catch (const simgrid::TimeoutException&) {
 527     status = SG_ERROR_TIMEOUT;
 528   } catch (const simgrid::CancelException&) {
 529     status = SG_ERROR_CANCELED;
 530   } catch (const simgrid::NetworkFailureException&) {
 531     status = SG_ERROR_NETWORK;
 532   }
 533   return status;
 534 }
 535
 536 void sg_comm_wait_all(sg_comm_t* comms, size_t count)
 537 {
 538   sg_comm_wait_all_for(comms, count, -1);
 539 }
 540
 541 size_t sg_comm_wait_all_for(sg_comm_t* comms, size_t count, double timeout)
 542 {
 543   std::vector<simgrid::s4u::CommPtr> s4u_comms;
 544   for (size_t i = 0; i < count; i++)
 545     s4u_comms.emplace_back(comms[i], false);
 546
 547   size_t pos = simgrid::s4u::Comm::wait_all_for(s4u_comms, timeout);
 548   for (size_t i = pos; i < count; i++)
 549     s4u_comms[i]->add_ref();
 550   return pos;
 551 }
 552
 553 ssize_t sg_comm_wait_any(sg_comm_t* comms, size_t count)
 554 {
 555   return sg_comm_wait_any_for(comms, count, -1);
 556 }
 557
 558 ssize_t sg_comm_wait_any_for(sg_comm_t* comms, size_t count, double timeout)
 559 {
 560   std::vector<simgrid::s4u::CommPtr> s4u_comms;
 561   for (size_t i = 0; i < count; i++)
 562     s4u_comms.emplace_back(comms[i], false);
 563
 564   ssize_t pos = simgrid::s4u::Comm::wait_any_for(s4u_comms, timeout);
 565   for (size_t i = 0; i < count; i++) {
 566     if (pos != -1 && static_cast<size_t>(pos) != i)
 567       s4u_comms[i]->add_ref();
 568   }
 569   return pos;
 570 }