--- /dev/null
+/* Copyright (c) 2010-2018. The SimGrid Team. All rights reserved. */
+
+/* This program is free software; you can redistribute it and/or modify it
+ * under the terms of the license (GNU LGPL) which comes with this package. */
+
+/* This example shows how to use simgrid::s4u::Mailbox::ready() to check for completed communications.
+ *
+ * We have a number of peers which send and receive messages in two phases:
+ * -> sending phase: each one of them sends a number of messages to the others followed
+ * by a single "finalize" message.
+ * -> receiving phase: each one of them receives all the available messages that reached
+ * their corresponding mailbox until it has all the needed "finalize"
+ * messages to know that no more work needs to be done.
+ *
+ * To avoid doing a wait() over the ongoing communications, each peer makes use of the
+ * simgrid::s4u::Mailbox::ready() method. If it returns true then a following get() will fetch the
+ * message immediately, if not the peer will sleep for a fixed amount of time before checking again.
+ *
+ */
+
+#include "simgrid/s4u.hpp"
+#include <cstdlib>
+#include <iostream>
+#include <string>
+
+XBT_LOG_NEW_DEFAULT_CATEGORY(msg_async_ready, "Messages specific for this s4u example");
+
+static int peer(int argc, char** argv)
+{
+ xbt_assert(argc == 5, "Expecting 4 parameters from the XML deployment file but got %d", argc);
+ int my_id = std::stoi(argv[1]); /* - my id */
+ long messages_count = std::stol(argv[2]); /* - number of tasks */
+ double msg_size = std::stol(argv[3]); /* - communication cost in bytes */
+ long peers_count = std::stod(argv[4]); /* - number of peers */
+
+ /* Set myself as the persistent receiver of my mailbox so that messages start flowing to me as soon as they are put into it */
+ simgrid::s4u::MailboxPtr my_mbox = simgrid::s4u::Mailbox::by_name(std::string("peer-") + std::to_string(my_id));
+ my_mbox->set_receiver(simgrid::s4u::Actor::self());
+
+ std::vector<simgrid::s4u::CommPtr> pending_comms;
+
+ /* Start dispatching all messages to peers others that myself */
+ for (int i = 0; i < messages_count; i++) {
+ for (int peer_id = 0; peer_id < peers_count; peer_id++) {
+ if (peer_id != my_id) {
+ std::string mboxName = std::string("peer-") + std::to_string(peer_id);
+ simgrid::s4u::MailboxPtr mbox = simgrid::s4u::Mailbox::by_name(mboxName);
+ std::string msgName = std::string("Message ") + std::to_string(i) + std::string(" from peer ") + std::to_string(my_id);
+ std::string* payload = new std::string(msgName); // copy the data we send:
+ // 'msgName' is not a stable storage location
+ XBT_INFO("Send '%s' to '%s'", msgName.c_str(), mboxName.c_str());
+ /* Create a communication representing the ongoing communication */
+ pending_comms.push_back(mbox->put_async(payload, msg_size));
+ }
+ }
+ }
+
+ /* Start sending messages to let peers know that they should stop */
+ for (int peer_id = 0; peer_id < peers_count; peer_id++) {
+ if (peer_id != my_id) {
+ std::string mboxName = std::string("peer-") + std::to_string(peer_id);
+ simgrid::s4u::MailboxPtr mbox = simgrid::s4u::Mailbox::by_name(mboxName);
+ std::string* payload = new std::string("finalize"); // Make a copy of the data we will send
+ pending_comms.push_back(mbox->put_async(payload, msg_size));
+ XBT_INFO("Send 'finalize' to 'peer-%d'", peer_id);
+ }
+ }
+ XBT_INFO("Done dispatching all messages");
+
+ /* Retrieve all the messages other peers have been sending to me until I receive all the corresponding "Finalize" messages */
+ int pending_finalize_messages = peers_count - 1;
+ while (pending_finalize_messages > 0) {
+ if (my_mbox->ready()) {
+ double start = simgrid::s4u::Engine::get_clock();
+ std::string* received = static_cast<std::string*>(my_mbox->get());
+ double waiting_time = simgrid::s4u::Engine::get_clock() - start;
+ xbt_assert(waiting_time == 0, "Expecting the waiting time to be 0 because the communication was supposedly ready, but got %f instead", waiting_time);
+ XBT_INFO("I got a '%s'.", received->c_str());
+ if (*received == "finalize") {
+ pending_finalize_messages--;
+ }
+ delete received;
+ } else {
+ XBT_INFO("Nothing ready to consume yet, I better sleep for a while");
+ simgrid::s4u::this_actor::sleep_for(.01);
+ }
+ }
+
+ XBT_INFO("I'm done, just waiting for my peers to receive the messages before exiting");
+ simgrid::s4u::Comm::wait_all(&pending_comms);
+
+ XBT_INFO("Goodbye now!");
+ return 0;
+}
+
+
+int main(int argc, char *argv[])
+{
+ xbt_assert(argc > 2, "Usage: %s platform_file deployment_file\n", argv[0]);
+
+ simgrid::s4u::Engine e(&argc, argv);
+ e.register_function("peer", &peer);
+
+ e.load_platform(argv[1]);
+ e.load_deployment(argv[2]);
+
+ e.run();
+
+ return 0;
+}
