-/* Copyright (c) 2009-2021. The SimGrid Team.
- * All rights reserved. */
+/* Copyright (c) 2009-2023. 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. */
/* simple test to schedule a DAX file with the Min-Min algorithm. */
-#include <math.h>
+#include <algorithm>
#include <simgrid/host.h>
#include <simgrid/s4u.hpp>
#include <string.h>
XBT_LOG_NEW_DEFAULT_CATEGORY(dag_scheduling, "Logging specific to this example");
+namespace sg4 = simgrid::s4u;
-typedef struct _HostAttribute* HostAttribute;
-struct _HostAttribute {
- /* Earliest time at which a host is ready to execute a task */
- double available_at;
- simgrid::s4u::Exec* last_scheduled_task;
-};
-
-static double sg_host_get_available_at(const simgrid::s4u::Host* host)
-{
- return static_cast<HostAttribute>(host->get_data())->available_at;
-}
-
-static void sg_host_set_available_at(simgrid::s4u::Host* host, double time)
-{
- auto* attr = static_cast<HostAttribute>(host->get_data());
- attr->available_at = time;
- host->set_data(attr);
-}
-
-static simgrid::s4u::Exec* sg_host_get_last_scheduled_task(const simgrid::s4u::Host* host)
-{
- return static_cast<HostAttribute>(host->get_data())->last_scheduled_task;
-}
-
-static void sg_host_set_last_scheduled_task(simgrid::s4u::Host* host, simgrid::s4u::ExecPtr task)
-{
- auto* attr = static_cast<HostAttribute>(host->get_data());
- attr->last_scheduled_task = task.get();
- host->set_data(attr);
-}
-
-static bool dependency_exists(const simgrid::s4u::Exec* src, simgrid::s4u::Exec* dst)
+static std::vector<sg4::Exec*> get_ready_tasks(const std::vector<sg4::ActivityPtr>& dax)
{
- const auto& dependencies = src->get_dependencies();
- const auto& successors = src->get_successors();
- return (std::find(successors.begin(), successors.end(), dst) != successors.end() ||
- dependencies.find(dst) != dependencies.end());
-}
-
-static std::vector<simgrid::s4u::Exec*> get_ready_tasks(const std::vector<simgrid::s4u::ActivityPtr>& dax)
-{
- std::vector<simgrid::s4u::Exec*> ready_tasks;
- std::map<simgrid::s4u::Exec*, unsigned int> candidate_execs;
+ std::vector<sg4::Exec*> ready_tasks;
+ std::map<sg4::Exec*, unsigned int> candidate_execs;
- for (auto& a : dax) {
- // Only loot at activity that have their dependencies solved but are not assigned
+ for (const auto& a : dax) {
+ // Only look at activity that have their dependencies solved but are not assigned
if (a->dependencies_solved() && not a->is_assigned()) {
// if it is an exec, it's ready
- auto* exec = dynamic_cast<simgrid::s4u::Exec*>(a.get());
- if (exec != nullptr)
+ if (auto* exec = dynamic_cast<sg4::Exec*>(a.get()))
ready_tasks.push_back(exec);
// if it a comm, we consider its successor as a candidate. If a candidate solves all its dependencies,
// i.e., get all its input data, it's ready
- const auto* comm = dynamic_cast<simgrid::s4u::Comm*>(a.get());
- if (comm != nullptr) {
- auto* next_exec = static_cast<simgrid::s4u::Exec*>(comm->get_successors().front().get());
+ if (const auto* comm = dynamic_cast<sg4::Comm*>(a.get())) {
+ auto* next_exec = static_cast<sg4::Exec*>(comm->get_successors().front().get());
candidate_execs[next_exec]++;
if (next_exec->get_dependencies().size() == candidate_execs[next_exec])
ready_tasks.push_back(next_exec);
return ready_tasks;
}
-static double finish_on_at(const simgrid::s4u::ExecPtr task, const simgrid::s4u::Host* host)
+static sg4::Host* get_best_host(const sg4::ExecPtr exec, double* min_finish_time)
{
- double result;
+ sg4::Host* best_host = nullptr;
+ *min_finish_time = std::numeric_limits<double>::max();
- const auto& parents = task->get_dependencies();
-
- if (not parents.empty()) {
- double data_available = 0.;
- double last_data_available;
+ for (const auto& host : sg4::Engine::get_instance()->get_all_hosts()) {
+ double data_available = 0.;
+ double last_data_available = -1.0;
/* compute last_data_available */
- last_data_available = -1.0;
- for (const auto& parent : parents) {
+ for (const auto& parent : exec->get_dependencies()) {
/* normal case */
- const auto* comm = dynamic_cast<simgrid::s4u::Comm*>(parent.get());
- if (comm != nullptr) {
- auto source = comm->get_source();
+ if (const auto* comm = dynamic_cast<sg4::Comm*>(parent.get())) {
+ const auto* source = comm->get_source();
XBT_DEBUG("transfer from %s to %s", source->get_cname(), host->get_cname());
/* Estimate the redistribution time from this parent */
double redist_time;
if (comm->get_remaining() <= 1e-6) {
redist_time = 0;
} else {
- redist_time = sg_host_get_route_latency(source, host) +
- comm->get_remaining() / sg_host_get_route_bandwidth(source, host);
+ double bandwidth = std::numeric_limits<double>::max();
+ auto [links, latency] = source->route_to(host);
+ for (auto const& link : links)
+ bandwidth = std::min(bandwidth, link->get_bandwidth());
+
+ redist_time = latency + comm->get_remaining() / bandwidth;
}
- // We use the user data field to store the finish time of the predecessor of the comm, i.e., its potential start
- // time
- data_available = *(static_cast<double*>(comm->get_data())) + redist_time;
+ // We use the user data field to store the finish time of the predecessor of the comm, i.e., its potential
+ // start time
+ data_available = *comm->get_data<double>() + redist_time;
}
- const auto* exec = dynamic_cast<simgrid::s4u::Exec*>(parent.get());
/* no transfer, control dependency */
- if (exec != nullptr) {
- data_available = exec->get_finish_time();
- }
+ if (const auto* parent_exec = dynamic_cast<sg4::Exec*>(parent.get()))
+ data_available = parent_exec->get_finish_time();
if (last_data_available < data_available)
last_data_available = data_available;
}
- result = fmax(sg_host_get_available_at(host), last_data_available) + task->get_remaining() / host->get_speed();
- } else
- result = sg_host_get_available_at(host) + task->get_remaining() / host->get_speed();
+ double finish_time = std::max(*host->get_data<double>(), last_data_available) +
+ exec->get_remaining() / host->get_speed();
- return result;
-}
+ XBT_DEBUG("%s finishes on %s at %f", exec->get_cname(), host->get_cname(), finish_time);
-static simgrid::s4u::Host* get_best_host(const simgrid::s4u::ExecPtr exec)
-{
- std::vector<simgrid::s4u::Host*> hosts = simgrid::s4u::Engine::get_instance()->get_all_hosts();
- auto best_host = hosts.front();
- double min_EFT = finish_on_at(exec, best_host);
+ if (finish_time < *min_finish_time) {
+ *min_finish_time = finish_time;
+ best_host = host;
+ }
+ }
- for (const auto& h : hosts) {
- double EFT = finish_on_at(exec, h);
- XBT_DEBUG("%s finishes on %s at %f", exec->get_cname(), h->get_cname(), EFT);
+ return best_host;
+}
- if (EFT < min_EFT) {
- min_EFT = EFT;
- best_host = h;
+static void schedule_on(sg4::ExecPtr exec, sg4::Host* host, double busy_until = 0.0)
+{
+ exec->set_host(host);
+ // We use the user data field to store up to when the host is busy
+ delete host->get_data<double>(); // In case we're erasing a previous value
+ host->set_data(new double(busy_until));
+ // we can also set the destination of all the input comms of this exec
+ for (const auto& pred : exec->get_dependencies()) {
+ auto* comm = dynamic_cast<sg4::Comm*>(pred.get());
+ if (comm != nullptr) {
+ comm->set_destination(host);
+ delete comm->get_data<double>();
}
}
- return best_host;
+ // we can also set the source of all the output comms of this exec
+ for (const auto& succ : exec->get_successors()) {
+ auto* comm = dynamic_cast<sg4::Comm*>(succ.get());
+ if (comm != nullptr)
+ comm->set_source(host);
+ }
}
int main(int argc, char** argv)
{
- double min_finish_time = -1.0;
- simgrid::s4u::Exec* selected_task = nullptr;
- simgrid::s4u::Host* selected_host = nullptr;
-
- simgrid::s4u::Engine e(&argc, argv);
- std::set<simgrid::s4u::Activity*> vetoed;
+ sg4::Engine e(&argc, argv);
+ std::set<sg4::Activity*> vetoed;
e.track_vetoed_activities(&vetoed);
- simgrid::s4u::Activity::on_completion_cb([](simgrid::s4u::Activity& activity) {
+ sg4::Exec::on_completion_cb([](sg4::Exec const& exec) {
// when an Exec completes, we need to set the potential start time of all its ouput comms
- const auto* exec = dynamic_cast<simgrid::s4u::Exec*>(&activity);
- if (exec == nullptr) // Only Execs are concerned here
- return;
- for (const auto& succ : exec->get_successors()) {
- auto* comm = dynamic_cast<simgrid::s4u::Comm*>(succ.get());
+ for (const auto& succ : exec.get_successors()) {
+ auto* comm = dynamic_cast<sg4::Comm*>(succ.get());
if (comm != nullptr) {
- auto* finish_time = new double(exec->get_finish_time());
+ auto* finish_time = new double(exec.get_finish_time());
// We use the user data field to store the finish time of the predecessor of the comm, i.e., its potential start
// time
comm->set_data(finish_time);
e.load_platform(argv[1]);
- /* Allocating the host attribute */
- unsigned long total_nhosts = e.get_host_count();
- const auto hosts = e.get_all_hosts();
-
- for (unsigned long i = 0; i < total_nhosts; i++)
- hosts[i]->set_data(xbt_new0(struct _HostAttribute, 1));
-
+ /* Mark all hosts as sequential, as it ought to be in such a scheduling example.
+ *
+ * It means that the hosts can only compute one thing at a given time. If an execution already takes place on a given
+ * host, any subsequently started execution will be queued until after the first execution terminates */
+ for (auto const& host : e.get_all_hosts()) {
+ host->set_concurrency_limit(1);
+ host->set_data(new double(0.0));
+ }
/* load the DAX file */
- std::vector<simgrid::s4u::ActivityPtr> dax = simgrid::s4u::create_DAG_from_DAX(argv[2]);
+ auto dax = sg4::create_DAG_from_DAX(argv[2]);
/* Schedule the root first */
- auto* root = static_cast<simgrid::s4u::Exec*>(dax.front().get());
- auto host = get_best_host(root);
- root->set_host(host);
- // we can also set the source of all the output comms of the root node
- for (const auto& succ : root->get_successors()) {
- auto* comm = dynamic_cast<simgrid::s4u::Comm*>(succ.get());
- if (comm != nullptr)
- comm->set_source(host);
- }
+ double root_finish_time;
+ auto* root = static_cast<sg4::Exec*>(dax.front().get());
+ auto* host = get_best_host(root, &root_finish_time);
+ schedule_on(root, host);
e.run();
vetoed.clear();
if (ready_tasks.empty()) {
- ready_tasks.clear();
- /* there is no ready task, let advance the simulation */
+ /* there is no ready exec, let advance the simulation */
e.run();
continue;
}
- /* For each ready task:
+ /* For each ready exec:
* get the host that minimizes the completion time.
- * select the task that has the minimum completion time on its best host.
+ * select the exec that has the minimum completion time on its best host.
*/
- for (auto task : ready_tasks) {
- XBT_DEBUG("%s is ready", task->get_cname());
- host = get_best_host(task);
- double finish_time = finish_on_at(task, host);
- if (min_finish_time < 0 || finish_time < min_finish_time) {
+ double min_finish_time = std::numeric_limits<double>::max();
+ sg4::Exec* selected_task = nullptr;
+ sg4::Host* selected_host = nullptr;
+
+ for (auto* exec : ready_tasks) {
+ XBT_DEBUG("%s is ready", exec->get_cname());
+ double finish_time;
+ host = get_best_host(exec, &finish_time);
+ if (finish_time < min_finish_time) {
min_finish_time = finish_time;
- selected_task = task;
+ selected_task = exec;
selected_host = host;
}
}
XBT_INFO("Schedule %s on %s", selected_task->get_cname(), selected_host->get_cname());
- selected_task->set_host(selected_host);
- // we can also set the destination of all the input comms of the selected task
- for (const auto& pred : selected_task->get_dependencies()) {
- auto* comm = dynamic_cast<simgrid::s4u::Comm*>(pred.get());
- if (comm != nullptr) {
- comm->set_destination(selected_host);
- delete static_cast<double*>(comm->get_data());
- }
- }
- // we can also set the source of all the output comms of the selected task
- for (const auto& succ : selected_task->get_successors()) {
- auto* comm = dynamic_cast<simgrid::s4u::Comm*>(succ.get());
- if (comm != nullptr)
- comm->set_source(selected_host);
- }
-
- /*
- * tasks can be executed concurrently when they can by default.
- * Yet schedulers take decisions assuming that tasks wait for resource availability to start.
- * The solution (well crude hack is to keep track of the last task scheduled on a host and add a special type of
- * dependency if needed to force the sequential execution meant by the scheduler.
- * If the last scheduled task is already done, has failed or is a predecessor of the current task, no need for a
- * new dependency
- */
-
- auto last_scheduled_task = sg_host_get_last_scheduled_task(selected_host);
- if (last_scheduled_task && (last_scheduled_task->get_state() != simgrid::s4u::Activity::State::FINISHED) &&
- (last_scheduled_task->get_state() != simgrid::s4u::Activity::State::FAILED) &&
- not dependency_exists(sg_host_get_last_scheduled_task(selected_host), selected_task))
- last_scheduled_task->add_successor(selected_task);
-
- sg_host_set_last_scheduled_task(selected_host, selected_task);
- sg_host_set_available_at(selected_host, min_finish_time);
+ schedule_on(selected_task, selected_host, min_finish_time);
ready_tasks.clear();
- /* reset the min_finish_time for the next set of ready tasks */
- min_finish_time = -1.;
e.run();
}
- XBT_INFO("Simulation Time: %f", simgrid_get_clock());
+ /* Cleanup memory */
+ for (auto const* h : e.get_all_hosts())
+ delete h->get_data<double>();
- for (auto h : hosts) {
- xbt_free(h->get_data());
- h->set_data(nullptr);
- }
+ XBT_INFO("Simulation Time: %f", simgrid_get_clock());
return 0;
}