1 /* Copyright (c) 2009-2023. 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 /* simple test to schedule a DAX file with the Min-Min algorithm. */
8 #include <simgrid/host.h>
9 #include <simgrid/s4u.hpp>
12 XBT_LOG_NEW_DEFAULT_CATEGORY(dag_scheduling, "Logging specific to this example");
13 namespace sg4 = simgrid::s4u;
15 static std::vector<sg4::Exec*> get_ready_tasks(const std::vector<sg4::ActivityPtr>& dax)
17 std::vector<sg4::Exec*> ready_tasks;
18 std::map<sg4::Exec*, unsigned int> candidate_execs;
21 // Only look at activity that have their dependencies solved but are not assigned
22 if (a->dependencies_solved() && not a->is_assigned()) {
23 // if it is an exec, it's ready
24 if (auto* exec = dynamic_cast<sg4::Exec*>(a.get()))
25 ready_tasks.push_back(exec);
26 // if it a comm, we consider its successor as a candidate. If a candidate solves all its dependencies,
27 // i.e., get all its input data, it's ready
28 if (const auto* comm = dynamic_cast<sg4::Comm*>(a.get())) {
29 auto* next_exec = static_cast<sg4::Exec*>(comm->get_successors().front().get());
30 candidate_execs[next_exec]++;
31 if (next_exec->get_dependencies().size() == candidate_execs[next_exec])
32 ready_tasks.push_back(next_exec);
36 XBT_DEBUG("There are %zu ready tasks", ready_tasks.size());
40 static double finish_on_at(const sg4::ExecPtr task, const sg4::Host* host)
42 double data_available = 0.;
43 double last_data_available = -1.0;
44 /* compute last_data_available */
45 for (const auto& parent : task->get_dependencies()) {
47 if (const auto* comm = dynamic_cast<sg4::Comm*>(parent.get())) {
48 auto source = comm->get_source();
49 XBT_DEBUG("transfer from %s to %s", source->get_cname(), host->get_cname());
50 /* Estimate the redistribution time from this parent */
52 if (comm->get_remaining() <= 1e-6) {
56 sg_host_get_route_latency(source, host) + comm->get_remaining() / sg_host_get_route_bandwidth(source, host);
58 // We use the user data field to store the finish time of the predecessor of the comm, i.e., its potential start
60 data_available = *comm->get_data<double>() + redist_time;
63 /* no transfer, control dependency */
64 if (const auto* exec = dynamic_cast<sg4::Exec*>(parent.get()))
65 data_available = exec->get_finish_time();
67 if (last_data_available < data_available)
68 last_data_available = data_available;
70 return std::max(*host->get_data<double>(), last_data_available) + task->get_remaining() / host->get_speed();
73 static sg4::Host* get_best_host(const sg4::ExecPtr exec)
75 auto hosts = sg4::Engine::get_instance()->get_all_hosts();
76 auto best_host = hosts.front();
77 double min_EFT = finish_on_at(exec, best_host);
79 for (const auto& h : hosts) {
80 double EFT = finish_on_at(exec, h);
81 XBT_DEBUG("%s finishes on %s at %f", exec->get_cname(), h->get_cname(), EFT);
91 static void schedule_on(sg4::ExecPtr exec, sg4::Host* host, double busy_until = 0.0)
94 // We use the user data field to store up to when the host is busy
95 host->set_data(new double(busy_until));
96 // we can also set the destination of all the input comms of this exec
97 for (const auto& pred : exec->get_dependencies()) {
98 auto* comm = dynamic_cast<sg4::Comm*>(pred.get());
99 if (comm != nullptr) {
100 comm->set_destination(host);
101 delete comm->get_data<double>();
104 // we can also set the source of all the output comms of this exec
105 for (const auto& succ : exec->get_successors()) {
106 auto* comm = dynamic_cast<sg4::Comm*>(succ.get());
108 comm->set_source(host);
112 int main(int argc, char** argv)
114 sg4::Engine e(&argc, argv);
115 std::set<sg4::Activity*> vetoed;
116 e.track_vetoed_activities(&vetoed);
118 sg4::Activity::on_completion_cb([](sg4::Activity const& activity) {
119 // when an Exec completes, we need to set the potential start time of all its ouput comms
120 const auto* exec = dynamic_cast<sg4::Exec const*>(&activity);
121 if (exec == nullptr) // Only Execs are concerned here
123 for (const auto& succ : exec->get_successors()) {
124 auto* comm = dynamic_cast<sg4::Comm*>(succ.get());
125 if (comm != nullptr) {
126 auto* finish_time = new double(exec->get_finish_time());
127 // We use the user data field to store the finish time of the predecessor of the comm, i.e., its potential start
129 comm->set_data(finish_time);
134 e.load_platform(argv[1]);
135 const auto hosts = e.get_all_hosts();
136 /* Mark all hosts as sequential, as it ought to be in such a scheduling example.
138 * It means that the hosts can only compute one thing at a given time. If an execution already takes place on a given
139 * host, any subsequently started execution will be queued until after the first execution terminates */
140 for (auto const& host : hosts) {
141 host->set_concurrency_limit(1);
142 host->set_data(new double(0.0));
144 /* load the DAX file */
145 auto dax = sg4::create_DAG_from_DAX(argv[2]);
147 /* Schedule the root first */
148 auto* root = static_cast<sg4::Exec*>(dax.front().get());
149 auto host = get_best_host(root);
150 schedule_on(root, host);
154 while (not vetoed.empty()) {
155 XBT_DEBUG("Start new scheduling round");
156 /* Get the set of ready tasks */
157 auto ready_tasks = get_ready_tasks(dax);
160 if (ready_tasks.empty()) {
161 /* there is no ready task, let advance the simulation */
165 /* For each ready task:
166 * get the host that minimizes the completion time.
167 * select the task that has the minimum completion time on its best host.
169 double min_finish_time = -1.0;
170 sg4::Exec* selected_task = nullptr;
171 sg4::Host* selected_host = nullptr;
173 for (auto task : ready_tasks) {
174 XBT_DEBUG("%s is ready", task->get_cname());
175 host = get_best_host(task);
176 double finish_time = finish_on_at(task, host);
177 if (min_finish_time < 0 || finish_time < min_finish_time) {
178 min_finish_time = finish_time;
179 selected_task = task;
180 selected_host = host;
184 XBT_INFO("Schedule %s on %s", selected_task->get_cname(), selected_host->get_cname());
185 schedule_on(selected_task, selected_host, min_finish_time);
191 XBT_INFO("Simulation Time: %f", simgrid_get_clock());