1 /* Copyright (c) 2010-2021. The SimGrid Team. All rights reserved. */
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. */
6 /* This example shows how to use simgrid::s4u::Mailbox::ready() to check for completed communications.
8 * We have a number of peers which send and receive messages in two phases:
9 * -> sending phase: each one of them sends a number of messages to the others followed
10 * by a single "finalize" message.
11 * -> receiving phase: each one of them receives all the available messages that reached
12 * their corresponding mailbox until it has all the needed "finalize"
13 * messages to know that no more work needs to be done.
15 * To avoid doing a wait() over the ongoing communications, each peer makes use of the
16 * simgrid::s4u::Mailbox::ready() method. If it returns true then a following get() will fetch the
17 * message immediately, if not the peer will sleep for a fixed amount of time before checking again.
21 #include "simgrid/s4u.hpp"
25 namespace sg4 = simgrid::s4u;
27 XBT_LOG_NEW_DEFAULT_CATEGORY(s4u_async_ready, "Messages specific for this s4u example");
29 static void peer(int argc, char** argv)
31 xbt_assert(argc == 5, "Expecting 4 parameters from the XML deployment file but got %d", argc);
32 int my_id = std::stoi(argv[1]); /* - my id */
33 long messages_count = std::stol(argv[2]); /* - number of message */
34 long msg_size = std::stol(argv[3]); /* - message size in bytes */
35 long peers_count = std::stol(argv[4]); /* - number of peers */
37 /* Set myself as the persistent receiver of my mailbox so that messages start flowing to me as soon as they are put
39 sg4::Mailbox* my_mbox = sg4::Mailbox::by_name(std::string("peer-") + std::to_string(my_id));
40 my_mbox->set_receiver(sg4::Actor::self());
42 std::vector<sg4::CommPtr> pending_comms;
44 /* Start dispatching all messages to peers others that myself */
45 for (int i = 0; i < messages_count; i++) {
46 for (int peer_id = 0; peer_id < peers_count; peer_id++) {
47 if (peer_id != my_id) {
48 std::string mboxName = std::string("peer-") + std::to_string(peer_id);
49 sg4::Mailbox* mbox = sg4::Mailbox::by_name(mboxName);
51 std::string("Message ") + std::to_string(i) + std::string(" from peer ") + std::to_string(my_id);
52 auto* payload = new std::string(msgName); // copy the data we send:
53 // 'msgName' is not a stable storage location
54 XBT_INFO("Send '%s' to '%s'", msgName.c_str(), mboxName.c_str());
55 /* Create a communication representing the ongoing communication */
56 pending_comms.push_back(mbox->put_async(payload, msg_size));
61 /* Start sending messages to let peers know that they should stop */
62 for (int peer_id = 0; peer_id < peers_count; peer_id++) {
63 if (peer_id != my_id) {
64 std::string mboxName = std::string("peer-") + std::to_string(peer_id);
65 sg4::Mailbox* mbox = sg4::Mailbox::by_name(mboxName);
66 auto* payload = new std::string("finalize"); // Make a copy of the data we will send
67 pending_comms.push_back(mbox->put_async(payload, msg_size));
68 XBT_INFO("Send 'finalize' to 'peer-%d'", peer_id);
71 XBT_INFO("Done dispatching all messages");
73 /* Retrieve all the messages other peers have been sending to me until I receive all the corresponding "Finalize"
75 long pending_finalize_messages = peers_count - 1;
76 while (pending_finalize_messages > 0) {
77 if (my_mbox->ready()) {
78 double start = sg4::Engine::get_clock();
79 auto received = my_mbox->get_unique<std::string>();
80 double waiting_time = sg4::Engine::get_clock() - start;
83 "Expecting the waiting time to be 0 because the communication was supposedly ready, but got %f instead",
85 XBT_INFO("I got a '%s'.", received->c_str());
86 if (*received == "finalize") {
87 pending_finalize_messages--;
90 XBT_INFO("Nothing ready to consume yet, I better sleep for a while");
91 sg4::this_actor::sleep_for(.01);
95 XBT_INFO("I'm done, just waiting for my peers to receive the messages before exiting");
96 sg4::Comm::wait_all(pending_comms);
98 XBT_INFO("Goodbye now!");
101 int main(int argc, char* argv[])
103 xbt_assert(argc > 2, "Usage: %s platform_file deployment_file\n", argv[0]);
105 sg4::Engine e(&argc, argv);
106 e.register_function("peer", &peer);
108 e.load_platform(argv[1]);
109 e.load_deployment(argv[2]);