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::this_actor::wait_any() to wait for the first occurring event.
8 * As for the other asynchronous examples, the sender initiate all the messages it wants to send and
9 * pack the resulting simgrid::s4u::CommPtr objects in a vector. All messages thus occur concurrently.
11 * The sender then loops until there is no ongoing communication. Using wait_any() ensures that the sender
12 * will notice events as soon as they occur even if it does not follow the order of the container.
14 * Here, finalize messages will terminate earlier because their size is 0, so they travel faster than the
15 * other messages of this application. As expected, the trace shows that the finalize of worker 1 is
16 * processed before 'Message 5' that is sent to worker 0.
20 #include "simgrid/s4u.hpp"
24 namespace sg4 = simgrid::s4u;
26 XBT_LOG_NEW_DEFAULT_CATEGORY(s4u_comm_waitall, "Messages specific for this s4u example");
29 long messages_count; /* - number of messages */
30 long receivers_count; /* - number of receivers */
31 long msg_size; /* - message size in bytes */
34 explicit Sender(std::vector<std::string> args)
36 xbt_assert(args.size() == 4, "Expecting 3 parameters from the XML deployment file but got %zu", args.size());
37 messages_count = std::stol(args[1]);
38 msg_size = std::stol(args[2]);
39 receivers_count = std::stol(args[3]);
41 void operator()() const
43 /* Vector in which we store all ongoing communications */
44 std::vector<sg4::CommPtr> pending_comms;
46 /* Make a vector of the mailboxes to use */
47 std::vector<sg4::Mailbox*> mboxes;
48 for (int i = 0; i < receivers_count; i++)
49 mboxes.push_back(sg4::Mailbox::by_name(std::string("receiver-") + std::to_string(i)));
51 /* Start dispatching all messages to receivers, in a round robin fashion */
52 for (int i = 0; i < messages_count; i++) {
53 std::string msg_content = std::string("Message ") + std::to_string(i);
54 // Copy the data we send: the 'msg_content' variable is not a stable storage location.
55 // It will be destroyed when this actor leaves the loop, ie before the receiver gets it
56 auto* payload = new std::string(msg_content);
58 XBT_INFO("Send '%s' to '%s'", msg_content.c_str(), mboxes[i % receivers_count]->get_cname());
60 /* Create a communication representing the ongoing communication, and store it in pending_comms */
61 sg4::CommPtr comm = mboxes[i % receivers_count]->put_async(payload, msg_size);
62 pending_comms.push_back(comm);
65 /* Start sending messages to let the workers know that they should stop */
66 for (int i = 0; i < receivers_count; i++) {
67 XBT_INFO("Send 'finalize' to 'receiver-%d'", i);
68 sg4::CommPtr comm = mboxes[i]->put_async(new std::string("finalize"), 0);
69 pending_comms.push_back(comm);
71 XBT_INFO("Done dispatching all messages");
73 /* Now that all message exchanges were initiated, wait for their completion, in order of termination.
75 * This loop waits for first terminating message with wait_any() and remove it with erase(), until all comms are
77 * Even in this simple example, the pending comms do not terminate in the exact same order of creation.
79 while (not pending_comms.empty()) {
80 int changed_pos = sg4::Comm::wait_any(&pending_comms);
81 pending_comms.erase(pending_comms.begin() + changed_pos);
83 XBT_INFO("Remove the %dth pending comm: it terminated earlier than another comm that was initiated first.",
87 XBT_INFO("Goodbye now!");
91 /* Receiver actor expects 1 argument: its ID */
96 explicit Receiver(std::vector<std::string> args)
98 xbt_assert(args.size() == 2, "Expecting one parameter from the XML deployment file but got %zu", args.size());
99 std::string mboxName = std::string("receiver-") + args[1];
100 mbox = sg4::Mailbox::by_name(mboxName);
104 XBT_INFO("Wait for my first message");
105 for (bool cont = true; cont;) {
106 auto received = mbox->get_unique<std::string>();
107 XBT_INFO("I got a '%s'.", received->c_str());
108 cont = (*received != "finalize"); // If it's a finalize message, we're done
109 // Receiving the message was all we were supposed to do
114 int main(int argc, char* argv[])
116 xbt_assert(argc > 2, "Usage: %s platform_file deployment_file\n", argv[0]);
118 sg4::Engine e(&argc, argv);
119 e.register_actor<Sender>("sender");
120 e.register_actor<Receiver>("receiver");
122 e.load_platform(argv[1]);
123 e.load_deployment(argv[2]);