X-Git-Url: http://info.iut-bm.univ-fcomte.fr/pub/gitweb/simgrid.git/blobdiff_plain/9f2dfd25486ba89c4adaa54d774092c0b9756361..1b211507e0c2abe5f2b7fbe56988af46d3189b51:/examples/cpp/task-switch-host/s4u-task-switch-host.cpp

diff --git a/examples/cpp/task-switch-host/s4u-task-switch-host.cpp b/examples/cpp/task-switch-host/s4u-task-switch-host.cpp
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+++ b/examples/cpp/task-switch-host/s4u-task-switch-host.cpp
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+/* Copyright (c) 2017-2023. 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. */
+
+/* This example demonstrates how to dynamically modify a graph of tasks.
+ *
+ * Assuming we have two instances of a service placed on different hosts,
+ * we want to send data alternatively to thoses instances.
+ *
+ * We consider the following graph:
+ *
+ * comm0 -> exec1 -> comm1
+ *     ↳-> exec2 ->comm2
+ *
+ * With exec1 and exec2 on different hosts.
+ */
+
+#include "simgrid/plugins/task.hpp"
+#include "simgrid/s4u.hpp"
+
+XBT_LOG_NEW_DEFAULT_CATEGORY(task_switch_host, "Messages specific for this task example");
+
+int main(int argc, char* argv[])
+{
+  simgrid::s4u::Engine e(&argc, argv);
+  e.load_platform(argv[1]);
+  simgrid::plugins::Task::init();
+
+  // Retrieve hosts
+  auto* tremblay = e.host_by_name("Tremblay");
+  auto* jupiter  = e.host_by_name("Jupiter");
+  auto* fafard   = e.host_by_name("Fafard");
+
+  // Create tasks
+  auto comm0 = simgrid::plugins::CommTask::init("comm0");
+  comm0->set_bytes(1e7);
+  comm0->set_source(tremblay);
+  auto exec1 = simgrid::plugins::ExecTask::init("exec1", 1e9, jupiter);
+  auto exec2 = simgrid::plugins::ExecTask::init("exec2", 1e9, fafard);
+  auto comm1 = simgrid::plugins::CommTask::init("comm1", 1e7, jupiter, tremblay);
+  auto comm2 = simgrid::plugins::CommTask::init("comm2", 1e7, fafard, tremblay);
+
+  // Create the initial graph by defining dependencies between tasks
+  comm0->add_successor(exec2);
+  exec1->add_successor(comm1);
+  exec2->add_successor(comm2);
+
+  // Add a function to be called when tasks end for log purpose
+  simgrid::plugins::Task::on_end_cb([](const simgrid::plugins::Task* t) {
+    XBT_INFO("Task %s finished (%d)", t->get_name().c_str(), t->get_count());
+  });
+
+  // Add a function to be called before each executions of comm0
+  // This function modifies the graph of tasks by adding or removing
+  // successors to comm0
+  comm0->on_this_start([exec1, exec2, jupiter, fafard](simgrid::plugins::Task* t) {
+    auto* comm0      = dynamic_cast<simgrid::plugins::CommTask*>(t);
+    static int count = 0;
+    if (count % 2 == 0) {
+      comm0->set_destination(jupiter);
+      comm0->add_successor(exec1);
+      comm0->remove_successor(exec2);
+    } else {
+      comm0->set_destination(fafard);
+      comm0->add_successor(exec2);
+      comm0->remove_successor(exec1);
+    }
+    count++;
+  });
+
+  // Enqueue four executions for task comm0
+  comm0->enqueue_execs(4);
+
+  // Start the simulation
+  e.run();
+  return 0;
+}