1 /* Copyright (c) 2010-2023. 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 build set custom communication factors
8 * It uses the netzone interface to register 2 callbacks that are called for every communications.
10 * These factors are used to change the communication time depending on the message size
13 * This example uses factors obtained by some experiments on dahu cluster in Grid'5000.
14 * You should change the values according to the calibration of your enviroment.
18 #include <simgrid/s4u.hpp>
19 namespace sg4 = simgrid::s4u;
21 XBT_LOG_NEW_DEFAULT_CATEGORY(s4u_network_factors, "Messages specific for this s4u example");
23 /* Factors used in this platform, for remote and local communications
24 * Obtained from dahu cluster. Obs.: just an example, change the values according
25 * to the calibration on your environment */
26 static const std::map<double, double> REMOTE_BW_FACTOR = {
27 {0, 1.0000000000000002}, {8000, 1.0000000000000002}, {15798, 0.07435006650635523},
28 {64000, 0.3163352696348148}, {6000000, 0.13003278960133288}, {42672591, 0.10354740223279707},
29 {160097505, 0.40258935729656503}};
30 static const std::map<double, double> LOCAL_BW_FACTOR = {{0, 0.17591906192813994},
31 {16000, 0.12119203247138953},
32 {6000000, 0.07551057012803415},
33 {36900419, 0.04281516758309203},
34 {160097505, 0.17440518795992602}};
36 static const std::map<double, double> REMOTE_LAT_FACTOR = {{0, 0.0},
37 {8000, 1731.7102918851567},
38 {15798, 1441.073993161278},
39 {64000, 1761.4784830658123},
42 {160097505, 970913.4558162984}};
43 static const std::map<double, double> LOCAL_LAT_FACTOR = {
44 {0, 0.0}, {16000, 650.2212383180362}, {6000000, 0.0}, {36900419, 0.0}, {160097505, 1017885.3518765072}};
46 /* bandwidth and latency used on the platform */
47 constexpr static double BW_REMOTE = 12.5e9;
48 constexpr static double BW_LOCAL = 25e9;
49 constexpr static double LATENCY = .1e-6;
51 /*************************************************************************************************/
52 /** @brief Create a simple platform based on Dahu cluster */
53 static void load_platform()
56 * Inspired on dahu cluster on Grenoble
62 * / / | | \ \ <-- 12.5GBps links
67 auto* root = sg4::create_star_zone("dahu");
68 std::string prefix = "dahu-";
69 std::string suffix = ".grid5000.fr";
71 for (int id = 0; id < 32; id++) {
72 std::string hostname = prefix + std::to_string(id) + suffix;
74 const sg4::Host* host = root->create_host(hostname, 1)->set_core_count(32)->seal();
75 /* create UP/DOWN link */
76 const sg4::Link* l = root->create_split_duplex_link(hostname, BW_REMOTE)->set_latency(LATENCY)->seal();
78 /* add link UP/DOWN for communications from the host */
79 root->add_route(host->get_netpoint(), nullptr, nullptr, nullptr, {{l, sg4::LinkInRoute::Direction::UP}}, true);
81 sg4::Link* loopback = root->create_link(hostname + "_loopback", BW_LOCAL)->set_latency(LATENCY)->seal();
82 root->add_route(host, host, {loopback});
88 /*************************************************************************************************/
89 /** @brief Auxiliary method to get factor for a message size */
90 static double get_factor_from_map(const std::map<double, double>& factors, double size)
93 for (auto const& [factor_size, factor_value] : factors) {
94 if (size < factor_size) {
97 factor = factor_value;
104 * @brief Callback to set latency factor for a communication
106 * Set different factors for local (loopback) and remote communications.
107 * Function signature is defined by API
109 * @param size Message size
110 * @param src Host origin
111 * @param dst Host destination
113 static double latency_factor_cb(double size, const sg4::Host* src, const sg4::Host* dst,
114 const std::vector<sg4::Link*>& /*links*/,
115 const std::unordered_set<sg4::NetZone*>& /*netzones*/)
117 if (src->get_name() == dst->get_name()) {
118 /* local communication factors */
119 return get_factor_from_map(LOCAL_LAT_FACTOR, size);
121 return get_factor_from_map(REMOTE_LAT_FACTOR, size);
126 * @brief Callback to set bandwidth factor for a communication
128 * Set different factors for local (loopback) and remote communications.
129 * Function signature is defined by API
131 * @param size Message size
132 * @param src Host origin
133 * @param dst Host destination
135 static double bandwidth_factor_cb(double size, const sg4::Host* src, const sg4::Host* dst,
136 const std::vector<sg4::Link*>& /*links*/,
137 const std::unordered_set<sg4::NetZone*>& /*netzones*/)
139 if (src->get_name() == dst->get_name()) {
140 /* local communication factors */
141 return get_factor_from_map(LOCAL_BW_FACTOR, size);
143 return get_factor_from_map(REMOTE_BW_FACTOR, size);
147 /*************************************************************************************************/
149 std::vector<sg4::Host*> hosts_;
150 double crosstraffic_ = 1.0;
153 explicit Sender(const std::vector<sg4::Host*>& hosts, bool crosstraffic) : hosts_{hosts}
156 crosstraffic_ = 1.05; // add crosstraffic load if it is enabled
158 void operator()() const
160 const std::vector<double> msg_sizes = {64e3, 64e6, 64e9}; // 64KB, 64MB, 64GB
162 for (double size : msg_sizes) {
163 for (const auto* host : hosts_) {
165 /* calculating the estimated communication time depending of message size and destination */
166 if (host->get_name() == sg4::this_actor::get_host()->get_name()) {
167 double lat_factor = get_factor_from_map(LOCAL_LAT_FACTOR, size);
168 double bw_factor = get_factor_from_map(LOCAL_BW_FACTOR, size);
169 /* Account for crosstraffic on local communications
170 * local communications use only a single link and crosstraffic impact on resource sharing
171 * on remote communications, we don't see this effect since we have split-duplex links */
173 sg4::Engine::get_clock() + size / (BW_LOCAL * bw_factor / crosstraffic_) + LATENCY * lat_factor;
175 msg = "Local communication: size=" + std::to_string(size) + ". Use bw_factor=" + std::to_string(bw_factor) +
176 " lat_factor=" + std::to_string(lat_factor) + ". Estimated finished time=" + std::to_string(est_time);
178 double lat_factor = get_factor_from_map(REMOTE_LAT_FACTOR, size);
179 double bw_factor = get_factor_from_map(REMOTE_BW_FACTOR, size);
180 double est_time = sg4::Engine::get_clock() + (size / (BW_REMOTE * bw_factor)) + LATENCY * lat_factor * 2;
181 msg = "Remote communication: size=" + std::to_string(size) + ". Use bw_factor=" + std::to_string(bw_factor) +
182 " lat_factor=" + std::to_string(lat_factor) + ". Estimated finished time=" + std::to_string(est_time);
185 /* Create a communication representing the ongoing communication */
186 auto* mbox = sg4::Mailbox::by_name(host->get_name());
187 auto* payload = new std::string(msg);
188 mbox->put(payload, static_cast<uint64_t>(size));
192 XBT_INFO("Done dispatching all messages");
193 /* sending message to stop receivers */
194 for (const auto* host : hosts_) {
195 auto* mbox = sg4::Mailbox::by_name(host->get_name());
196 mbox->put(new std::string("finalize"), 0);
201 /* Receiver actor: wait for messages on the mailbox identified by the hostname */
204 void operator()() const
206 auto* mbox = sg4::Mailbox::by_name(sg4::this_actor::get_host()->get_name());
207 // Receiving the message was all we were supposed to do
208 for (bool cont = true; cont;) {
209 auto received = mbox->get_unique<std::string>();
210 XBT_INFO("I got a '%s'.", received->c_str());
211 cont = (*received != "finalize"); // If it's a finalize message, we're done
216 /*************************************************************************************************/
217 int main(int argc, char* argv[])
219 bool crosstraffic = true;
220 sg4::Engine e(&argc, argv);
221 /* setting network model to default one */
222 sg4::Engine::set_config("network/model:CM02");
224 /* test with crosstraffic disabled */
225 if (argc == 2 && std::string(argv[1]) == "disable_crosstraffic") {
226 sg4::Engine::set_config("network/crosstraffic:0");
227 crosstraffic = false;
230 /* create platform */
232 /* setting network factors callbacks */
233 e.get_netzone_root()->set_latency_factor_cb(latency_factor_cb);
234 e.get_netzone_root()->set_bandwidth_factor_cb(bandwidth_factor_cb);
236 sg4::Host* host = e.host_by_name("dahu-1.grid5000.fr");
237 sg4::Host* host_remote = e.host_by_name("dahu-10.grid5000.fr");
238 sg4::Actor::create("receiver-local", host, Receiver());
239 sg4::Actor::create("receiver-remote", host_remote, Receiver());
240 sg4::Actor::create("sender" + host->get_name(), host, Sender({host, host_remote}, crosstraffic));
242 /* runs the simulation */