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 build set customized communication factors
8 * It uses the interface provided by NetworkModelIntf to register 2 callbacks that
9 * are called everytime a communication occurs.
11 * These factors are used to change the communication time depending on the message size
14 * This example uses factors obtained by some experiments on dahu cluster in Grid'5000.
15 * You must change the values according to the calibration of your enviroment.
19 #include <simgrid/kernel/resource/NetworkModelIntf.hpp>
20 #include <simgrid/s4u.hpp>
21 namespace sg4 = simgrid::s4u;
23 XBT_LOG_NEW_DEFAULT_CATEGORY(s4u_network_factors, "Messages specific for this s4u example");
25 /* Factors used in this platform, for remote and local communications
26 * Obtained from dahu cluster. Obs.: just an example, change the values according
27 * to the calibration on your environment */
28 static const std::map<double, double> REMOTE_BW_FACTOR = {
29 {0, 1.0000000000000002}, {8000, 1.0000000000000002}, {15798, 0.07435006650635523},
30 {64000, 0.3163352696348148}, {6000000, 0.13003278960133288}, {42672591, 0.10354740223279707},
31 {160097505, 0.40258935729656503}};
32 static const std::map<double, double> LOCAL_BW_FACTOR = {{0, 0.17591906192813994},
33 {16000, 0.12119203247138953},
34 {6000000, 0.07551057012803415},
35 {36900419, 0.04281516758309203},
36 {160097505, 0.17440518795992602}};
38 static const std::map<double, double> REMOTE_LAT_FACTOR = {{0, 0.0},
39 {8000, 1731.7102918851567},
40 {15798, 1441.073993161278},
41 {64000, 1761.4784830658123},
44 {160097505, 970913.4558162984}};
45 static const std::map<double, double> LOCAL_LAT_FACTOR = {
46 {0, 0.0}, {16000, 650.2212383180362}, {6000000, 0.0}, {36900419, 0.0}, {160097505, 1017885.3518765072}};
48 /* bandwidth and latency used on the platform */
49 constexpr static double BW_REMOTE = 12.5e9;
50 constexpr static double BW_LOCAL = 25e9;
51 constexpr static double LATENCY = .1e-6;
53 /*************************************************************************************************/
54 /** @brief Create a simple platform based on Dahu cluster */
55 static void load_platform()
58 * Inspired on dahu cluster on Grenoble
64 * / / | | \ \ <-- 12.5GBps links
69 auto* root = sg4::create_star_zone("dahu");
70 std::string prefix = "dahu-";
71 std::string suffix = ".grid5000.fr";
73 for (int id = 0; id < 32; id++) {
74 std::string hostname = prefix + std::to_string(id) + suffix;
76 const sg4::Host* host = root->create_host(hostname, 1)->set_core_count(32)->seal();
77 /* create UP/DOWN link */
78 sg4::Link* l_up = root->create_link(hostname + "_up", BW_REMOTE)->set_latency(LATENCY)->seal();
79 sg4::Link* l_down = root->create_link(hostname + "_down", BW_REMOTE)->set_latency(LATENCY)->seal();
81 /* add link UP/DOWN for communications from the host */
82 root->add_route(host->get_netpoint(), nullptr, nullptr, nullptr, std::vector<sg4::Link*>{l_up}, false);
83 root->add_route(nullptr, host->get_netpoint(), nullptr, nullptr, std::vector<sg4::Link*>{l_down}, false);
85 sg4::Link* loopback = root->create_link(hostname + "_loopback", BW_LOCAL)->set_latency(LATENCY)->seal();
86 root->add_route(host->get_netpoint(), host->get_netpoint(), nullptr, nullptr, std::vector<sg4::Link*>{loopback});
92 /*************************************************************************************************/
93 /** @brief Auxiliary method to get factor for a message size */
94 static double get_factor_from_map(const std::map<double, double>& factors, double size)
97 for (auto const& fact : factors) {
98 if (size < fact.first) {
101 factor = fact.second;
108 * @brief Callback to set latency factor for a communication
110 * Set different factors for local (loopback) and remote communications.
111 * Function signature is defined by API
113 * @param size Message size
114 * @param src Host origin
115 * @param dst Host destination
117 static double latency_factor_cb(double size, const sg4::Host* src, const sg4::Host* dst,
118 const std::vector<sg4::Link*>& /*links*/,
119 const std::unordered_set<sg4::NetZone*>& /*netzones*/)
121 if (src->get_name() == dst->get_name()) {
122 /* local communication factors */
123 return get_factor_from_map(LOCAL_LAT_FACTOR, size);
125 return get_factor_from_map(REMOTE_LAT_FACTOR, size);
130 * @brief Callback to set bandwidth factor for a communication
132 * Set different factors for local (loopback) and remote communications.
133 * Function signature is defined by API
135 * @param size Message size
136 * @param src Host origin
137 * @param dst Host destination
139 static double bandwidth_factor_cb(double size, const sg4::Host* src, const sg4::Host* dst,
140 const std::vector<sg4::Link*>& /*links*/,
141 const std::unordered_set<sg4::NetZone*>& /*netzones*/)
143 if (src->get_name() == dst->get_name()) {
144 /* local communication factors */
145 return get_factor_from_map(LOCAL_BW_FACTOR, size);
147 return get_factor_from_map(REMOTE_BW_FACTOR, size);
151 /*************************************************************************************************/
153 std::vector<sg4::Host*> hosts_;
154 double crosstraffic_ = 1.0;
157 explicit Sender(const std::vector<sg4::Host*>& hosts, bool crosstraffic) : hosts_{hosts}
160 crosstraffic_ = 1.05; // add crosstraffic load if it is enabled
162 void operator()() const
164 const std::vector<double> msg_sizes = {64e3, 64e6, 64e9}; // 64KB, 64MB, 64GB
166 for (double size : msg_sizes) {
167 for (const auto* host : hosts_) {
169 /* calculating the estimated communication time depending of message size and destination */
170 if (host->get_name() == sg4::this_actor::get_host()->get_name()) {
171 double lat_factor = get_factor_from_map(LOCAL_LAT_FACTOR, size);
172 double bw_factor = get_factor_from_map(LOCAL_BW_FACTOR, size);
173 /* Account for crosstraffic on local communications
174 * local communications use only a single link and crosstraffic impact on resource sharing
175 * on remote communications, we don't see this effect since we have split-duplex links */
177 sg4::Engine::get_clock() + size / (BW_LOCAL * bw_factor / crosstraffic_) + LATENCY * lat_factor;
179 msg = "Local communication: size=" + std::to_string(size) + ". Use bw_factor=" + std::to_string(bw_factor) +
180 " lat_factor=" + std::to_string(lat_factor) + ". Estimated finished time=" + std::to_string(est_time);
182 double lat_factor = get_factor_from_map(REMOTE_LAT_FACTOR, size);
183 double bw_factor = get_factor_from_map(REMOTE_BW_FACTOR, size);
184 double est_time = sg4::Engine::get_clock() + (size / (BW_REMOTE * bw_factor)) + LATENCY * lat_factor * 2;
185 msg = "Remote communication: size=" + std::to_string(size) + ". Use bw_factor=" + std::to_string(bw_factor) +
186 " lat_factor=" + std::to_string(lat_factor) + ". Estimated finished time=" + std::to_string(est_time);
189 /* Create a communication representing the ongoing communication */
190 auto mbox = sg4::Mailbox::by_name(host->get_name());
191 auto* payload = new std::string(msg);
192 mbox->put(payload, static_cast<uint64_t>(size));
196 XBT_INFO("Done dispatching all messages");
197 /* sending message to stop receivers */
198 for (const auto* host : hosts_) {
199 auto mbox = sg4::Mailbox::by_name(host->get_name());
200 mbox->put(new std::string("finalize"), 0);
205 /* Receiver actor: wait for messages on the mailbox identified by the hostname */
208 void operator()() const
210 auto mbox = sg4::Mailbox::by_name(sg4::this_actor::get_host()->get_name());
211 // Receiving the message was all we were supposed to do
212 for (bool cont = true; cont;) {
213 auto received = mbox->get_unique<std::string>();
214 XBT_INFO("I got a '%s'.", received->c_str());
215 cont = (*received != "finalize"); // If it's a finalize message, we're done
220 /*************************************************************************************************/
221 int main(int argc, char* argv[])
223 bool crosstraffic = true;
224 sg4::Engine e(&argc, argv);
225 /* setting network model to default one */
226 sg4::Engine::set_config("network/model:CM02");
228 /* test with crosstraffic disabled */
229 if (argc == 2 && std::string(argv[1]) == "disable_crosstraffic") {
230 sg4::Engine::set_config("network/crosstraffic:0");
231 crosstraffic = false;
234 /* create platform */
236 /* setting network factors callbacks */
237 simgrid::kernel::resource::NetworkModelIntf* model = e.get_netzone_root()->get_network_model();
238 model->set_lat_factor_cb(latency_factor_cb);
239 model->set_bw_factor_cb(bandwidth_factor_cb);
241 sg4::Host* host = e.host_by_name("dahu-1.grid5000.fr");
242 sg4::Host* host_remote = e.host_by_name("dahu-10.grid5000.fr");
243 sg4::Actor::create(std::string("receiver-local"), host, Receiver());
244 sg4::Actor::create(std::string("receiver-remote"), host_remote, Receiver());
245 sg4::Actor::create(std::string("sender") + std::string(host->get_name()), host,
246 Sender({host, host_remote}, crosstraffic));
248 /* runs the simulation */