SimGrid  3.18
Versatile Simulation of Distributed Systems
examples/s4u/async-waitany/s4u-async-waitany.cpp
/* Copyright (c) 2010-2017. 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::this_actor::wait_any() to wait for the first occurring event.
*
* As for the other asynchronous examples, the sender initiate all the messages it wants to send and
* pack the resulting simgrid::s4u::CommPtr objects in a vector. All messages thus occurs concurrently.
*
* The sender then loops until there is no ongoing communication. Using wait_any() ensures that the sender
* will notice events as soon as they occur even if it does not follow the order of the container.
*
* Here, finalize messages will terminate earlier because their size is 0, so they travel faster than the
* other messages of this application. As expected, the trace shows that the finalize of worker 1 is
* processed before 'Message 5' that is sent to worker 0.
*
*/
#include "simgrid/s4u.hpp"
#include <cstdlib>
#include <iostream>
#include <string>
XBT_LOG_NEW_DEFAULT_CATEGORY(msg_async_waitall, "Messages specific for this msg example");
class Sender {
long messages_count; /* - number of tasks */
long receivers_count; /* - number of receivers */
double msg_size; /* - communication cost in bytes */
public:
explicit Sender(std::vector<std::string> args)
{
xbt_assert(args.size() == 4, "Expecting 3 parameters from the XML deployment file but got %zu", args.size());
messages_count = std::stol(args[1]);
msg_size = std::stod(args[2]);
receivers_count = std::stol(args[3]);
}
void operator()()
{
std::vector<simgrid::s4u::CommPtr> pending_comms;
/* Start dispatching all messages to receivers, in a round robin fashion */
for (int i = 0; i < messages_count; i++) {
std::string mboxName = std::string("receiver-") + std::to_string(i % receivers_count);
std::string msgName = std::string("Message ") + std::to_string(i);
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 */
simgrid::s4u::CommPtr comm = mbox->put_async(payload, msg_size);
/* Add this comm to the vector of all known comms */
pending_comms.push_back(comm);
}
/* Start sending messages to let the workers know that they should stop */
for (int i = 0; i < receivers_count; i++) {
std::string mboxName = std::string("receiver-") + std::to_string(i % receivers_count);
std::string* payload = new std::string("finalize"); // Make a copy of the data we will send
simgrid::s4u::CommPtr comm = mbox->put_async(payload, 0);
pending_comms.push_back(comm);
XBT_INFO("Send 'finalize' to 'receiver-%ld'", i % receivers_count);
}
XBT_INFO("Done dispatching all messages");
/* Now that all message exchanges were initiated, wait for their completion, in order of termination.
*
* This loop waits for first terminating message with wait_any() and remove it with erase(), until all comms are
* terminated
* Even in this simple example, the pending comms do not terminate in the exact same order of creation.
*/
while (not pending_comms.empty()) {
int changed_pos = simgrid::s4u::Comm::wait_any(&pending_comms);
pending_comms.erase(pending_comms.begin() + changed_pos);
if (changed_pos != 0)
XBT_INFO("Remove the %dth pending comm: it terminated earlier than another comm that was initiated first.",
changed_pos);
}
XBT_INFO("Goodbye now!");
}
};
/* Receiver actor expects 1 argument: its ID */
class Receiver {
public:
explicit Receiver(std::vector<std::string> args)
{
xbt_assert(args.size() == 2, "Expecting one parameter from the XML deployment file but got %zu", args.size());
std::string mboxName = std::string("receiver-") + args[1];
}
void operator()()
{
XBT_INFO("Wait for my first message");
for (bool cont = true; cont;) {
std::string* received = static_cast<std::string*>(mbox->get());
XBT_INFO("I got a '%s'.", received->c_str());
cont = (*received != "finalize"); // If it's a finalize message, we're done
// Receiving the message was all we were supposed to do
delete received;
}
}
};
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.registerFunction<Sender>("sender");
e.registerFunction<Receiver>("receiver");
e.loadPlatform(argv[1]);
e.loadDeployment(argv[2]);
e.run();
return 0;
}