1 /* Copyright (c) 2009-2021. The SimGrid Team.
2 * All rights reserved. */
4 /* This program is free software; you can redistribute it and/or modify it
5 * under the terms of the license (GNU LGPL) which comes with this package. */
7 /* simple test to schedule a DAX file with the Min-Min algorithm. */
9 #include <simgrid/host.h>
10 #include <simgrid/s4u.hpp>
13 XBT_LOG_NEW_DEFAULT_CATEGORY(dag_scheduling, "Logging specific to this example");
15 typedef struct _HostAttribute* HostAttribute;
16 struct _HostAttribute {
17 /* Earliest time at which a host is ready to execute a task */
19 simgrid::s4u::Exec* last_scheduled_task;
22 static double sg_host_get_available_at(const simgrid::s4u::Host* host)
24 return static_cast<HostAttribute>(host->get_data())->available_at;
27 static void sg_host_set_available_at(simgrid::s4u::Host* host, double time)
29 auto* attr = static_cast<HostAttribute>(host->get_data());
30 attr->available_at = time;
34 static simgrid::s4u::Exec* sg_host_get_last_scheduled_task(const simgrid::s4u::Host* host)
36 return static_cast<HostAttribute>(host->get_data())->last_scheduled_task;
39 static void sg_host_set_last_scheduled_task(simgrid::s4u::Host* host, simgrid::s4u::ExecPtr task)
41 auto* attr = static_cast<HostAttribute>(host->get_data());
42 attr->last_scheduled_task = task.get();
46 static bool dependency_exists(const simgrid::s4u::Exec* src, simgrid::s4u::Exec* dst)
48 const auto& dependencies = src->get_dependencies();
49 const auto& successors = src->get_successors();
50 return (std::find(successors.begin(), successors.end(), dst) != successors.end() ||
51 dependencies.find(dst) != dependencies.end());
54 static std::vector<simgrid::s4u::Exec*> get_ready_tasks(const std::vector<simgrid::s4u::ActivityPtr>& dax)
56 std::vector<simgrid::s4u::Exec*> ready_tasks;
57 std::map<simgrid::s4u::Exec*, unsigned int> candidate_execs;
60 // Only loot at activity that have their dependencies solved but are not assigned
61 if (a->dependencies_solved() && not a->is_assigned()) {
62 // if it is an exec, it's ready
63 auto* exec = dynamic_cast<simgrid::s4u::Exec*>(a.get());
65 ready_tasks.push_back(exec);
66 // if it a comm, we consider its successor as a candidate. If a candidate solves all its dependencies,
67 // i.e., get all its input data, it's ready
68 const auto* comm = dynamic_cast<simgrid::s4u::Comm*>(a.get());
69 if (comm != nullptr) {
70 auto* next_exec = static_cast<simgrid::s4u::Exec*>(comm->get_successors().front().get());
71 candidate_execs[next_exec]++;
72 if (next_exec->get_dependencies().size() == candidate_execs[next_exec])
73 ready_tasks.push_back(next_exec);
77 XBT_DEBUG("There are %zu ready tasks", ready_tasks.size());
81 static double finish_on_at(const simgrid::s4u::ExecPtr task, const simgrid::s4u::Host* host)
85 const auto& parents = task->get_dependencies();
87 if (not parents.empty()) {
88 double data_available = 0.;
89 double last_data_available;
90 /* compute last_data_available */
91 last_data_available = -1.0;
92 for (const auto& parent : parents) {
94 const auto* comm = dynamic_cast<simgrid::s4u::Comm*>(parent.get());
95 if (comm != nullptr) {
96 auto source = comm->get_source();
97 XBT_DEBUG("transfer from %s to %s", source->get_cname(), host->get_cname());
98 /* Estimate the redistribution time from this parent */
100 if (comm->get_remaining() <= 1e-6) {
103 redist_time = sg_host_get_route_latency(source, host) +
104 comm->get_remaining() / sg_host_get_route_bandwidth(source, host);
106 // We use the user data field to store the finish time of the predecessor of the comm, i.e., its potential start
108 data_available = *(static_cast<double*>(comm->get_data())) + redist_time;
111 const auto* exec = dynamic_cast<simgrid::s4u::Exec*>(parent.get());
112 /* no transfer, control dependency */
113 if (exec != nullptr) {
114 data_available = exec->get_finish_time();
117 if (last_data_available < data_available)
118 last_data_available = data_available;
121 result = fmax(sg_host_get_available_at(host), last_data_available) + task->get_remaining() / host->get_speed();
123 result = sg_host_get_available_at(host) + task->get_remaining() / host->get_speed();
128 static simgrid::s4u::Host* get_best_host(const simgrid::s4u::ExecPtr exec)
130 std::vector<simgrid::s4u::Host*> hosts = simgrid::s4u::Engine::get_instance()->get_all_hosts();
131 auto best_host = hosts.front();
132 double min_EFT = finish_on_at(exec, best_host);
134 for (const auto& h : hosts) {
135 double EFT = finish_on_at(exec, h);
136 XBT_DEBUG("%s finishes on %s at %f", exec->get_cname(), h->get_cname(), EFT);
146 int main(int argc, char** argv)
148 double min_finish_time = -1.0;
149 simgrid::s4u::Exec* selected_task = nullptr;
150 simgrid::s4u::Host* selected_host = nullptr;
152 simgrid::s4u::Engine e(&argc, argv);
153 std::set<simgrid::s4u::Activity*> vetoed;
154 e.track_vetoed_activities(&vetoed);
156 simgrid::s4u::Activity::on_completion_cb([](simgrid::s4u::Activity& activity) {
157 // when an Exec completes, we need to set the potential start time of all its ouput comms
158 const auto* exec = dynamic_cast<simgrid::s4u::Exec*>(&activity);
159 if (exec == nullptr) // Only Execs are concerned here
161 for (const auto& succ : exec->get_successors()) {
162 auto* comm = dynamic_cast<simgrid::s4u::Comm*>(succ.get());
163 if (comm != nullptr) {
164 auto* finish_time = new double(exec->get_finish_time());
165 // We use the user data field to store the finish time of the predecessor of the comm, i.e., its potential start
167 comm->set_data(finish_time);
172 e.load_platform(argv[1]);
174 /* Allocating the host attribute */
175 unsigned long total_nhosts = e.get_host_count();
176 const auto hosts = e.get_all_hosts();
178 for (unsigned long i = 0; i < total_nhosts; i++)
179 hosts[i]->set_data(xbt_new0(struct _HostAttribute, 1));
181 /* load the DAX file */
182 std::vector<simgrid::s4u::ActivityPtr> dax = simgrid::s4u::create_DAG_from_DAX(argv[2]);
184 /* Schedule the root first */
185 auto* root = static_cast<simgrid::s4u::Exec*>(dax.front().get());
186 auto host = get_best_host(root);
187 root->set_host(host);
188 // we can also set the source of all the output comms of the root node
189 for (const auto& succ : root->get_successors()) {
190 auto* comm = dynamic_cast<simgrid::s4u::Comm*>(succ.get());
192 comm->set_source(host);
197 while (not vetoed.empty()) {
198 XBT_DEBUG("Start new scheduling round");
199 /* Get the set of ready tasks */
200 auto ready_tasks = get_ready_tasks(dax);
203 if (ready_tasks.empty()) {
205 /* there is no ready task, let advance the simulation */
209 /* For each ready task:
210 * get the host that minimizes the completion time.
211 * select the task that has the minimum completion time on its best host.
213 for (auto task : ready_tasks) {
214 XBT_DEBUG("%s is ready", task->get_cname());
215 host = get_best_host(task);
216 double finish_time = finish_on_at(task, host);
217 if (min_finish_time < 0 || finish_time < min_finish_time) {
218 min_finish_time = finish_time;
219 selected_task = task;
220 selected_host = host;
224 XBT_INFO("Schedule %s on %s", selected_task->get_cname(), selected_host->get_cname());
225 selected_task->set_host(selected_host);
226 // we can also set the destination of all the input comms of the selected task
227 for (const auto& pred : selected_task->get_dependencies()) {
228 auto* comm = dynamic_cast<simgrid::s4u::Comm*>(pred.get());
229 if (comm != nullptr) {
230 comm->set_destination(selected_host);
231 delete static_cast<double*>(comm->get_data());
234 // we can also set the source of all the output comms of the selected task
235 for (const auto& succ : selected_task->get_successors()) {
236 auto* comm = dynamic_cast<simgrid::s4u::Comm*>(succ.get());
238 comm->set_source(selected_host);
242 * tasks can be executed concurrently when they can by default.
243 * Yet schedulers take decisions assuming that tasks wait for resource availability to start.
244 * The solution (well crude hack is to keep track of the last task scheduled on a host and add a special type of
245 * dependency if needed to force the sequential execution meant by the scheduler.
246 * If the last scheduled task is already done, has failed or is a predecessor of the current task, no need for a
250 auto last_scheduled_task = sg_host_get_last_scheduled_task(selected_host);
251 if (last_scheduled_task && (last_scheduled_task->get_state() != simgrid::s4u::Activity::State::FINISHED) &&
252 (last_scheduled_task->get_state() != simgrid::s4u::Activity::State::FAILED) &&
253 not dependency_exists(sg_host_get_last_scheduled_task(selected_host), selected_task))
254 last_scheduled_task->add_successor(selected_task);
256 sg_host_set_last_scheduled_task(selected_host, selected_task);
257 sg_host_set_available_at(selected_host, min_finish_time);
260 /* reset the min_finish_time for the next set of ready tasks */
261 min_finish_time = -1.;
265 XBT_INFO("Simulation Time: %f", simgrid_get_clock());
267 for (auto h : hosts) {
268 xbt_free(h->get_data());
269 h->set_data(nullptr);