+static simgrid::plugin::loadbalancer::LoadBalancer lb;
+
+class MigrateParser : public simgrid::smpi::replay::ActionArgParser {
+public:
+ double memory_consumption;
+ void parse(simgrid::xbt::ReplayAction& action, const std::string&)
+ {
+ // The only parameter is the amount of memory used by the current process.
+ CHECK_ACTION_PARAMS(action, 1, 0);
+ memory_consumption = std::stod(action[2]);
+ }
+};
+
+/* This function simulates what happens when the original application calls
+ * (A)MPI_Migrate. It executes the load balancing heuristics, makes the necessary
+ * migrations and updates the task mapping in the load balancer.
+ */
+class MigrateAction : public simgrid::smpi::replay::ReplayAction<simgrid::smpi::plugin::MigrateParser> {
+public:
+ explicit MigrateAction() : ReplayAction("Migrate") {}
+ void kernel(simgrid::xbt::ReplayAction&)
+ {
+ static std::map<simgrid::s4u::ActorPtr, int> migration_call_counter;
+ static simgrid::s4u::Barrier smpilb_bar(smpi_process_count());
+ simgrid::s4u::Host* cur_host = simgrid::s4u::this_actor::get_host();
+ simgrid::s4u::Host* migrate_to_host;
+
+ TRACE_migration_call(my_proc_id, nullptr);
+
+ // We only migrate every "cfg_migration_frequency"-times, not at every call
+ migration_call_counter[simgrid::s4u::Actor::self()]++;
+ if ((migration_call_counter[simgrid::s4u::Actor::self()] % simgrid::config::get_value<int>(cfg_migration_frequency.get_name())) != 0) {
+ return;
+ }
+
+ // TODO cheinrich: Why do we need this barrier?
+ smpilb_bar.wait();
+
+ static bool was_executed = false;
+ if (not was_executed) {
+ was_executed = true;
+ XBT_DEBUG("Process %li runs the load balancer", my_proc_id);
+ smpi_bench_begin();
+ lb.run();
+ smpi_bench_end();
+ }
+
+ // This barrier is required to ensure that the mapping has been computed and is available
+ smpilb_bar.wait();
+ was_executed = false; // Must stay behind this barrier so that all processes have passed the if clause
+
+ migrate_to_host = lb.get_mapping(simgrid::s4u::Actor::self());
+ if (cur_host != migrate_to_host) { // Origin and dest are not the same -> migrate
+ std::vector<simgrid::s4u::Host*> migration_hosts = {cur_host, migrate_to_host};
+ std::vector<double> comp_amount = {0, 0};
+ std::vector<double> comm_amount = {0, /*must not be 0*/ std::max(args.memory_consumption, 1.0), 0, 0};