1 /* Copyright (c) 2017-2018. 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 /* Parallel tasks are convenient abstractions of parallel computational kernels that span over several machines.
7 * To create a new one, you have to provide several things:
8 * - a vector of hosts on which the task will execute
9 * - a vector of values, the amount of computation for each of the hosts (in flops)
10 * - a matrix of values, the amount of communication between each pair of hosts (in bytes)
12 * Each of these operation will be processed at the same relative speed.
13 * This means that at some point in time, all sub-executions and all sub-communications will be at 20% of completion.
14 * Also, they will all complete at the exact same time.
16 * This is obviously a simplistic abstraction, but this is very handful in a large amount of situations.
18 * Please note that you must have the LV07 platform model enabled to use such constructs.
21 #include "simgrid/plugins/energy.h"
22 #include <simgrid/s4u.hpp>
24 XBT_LOG_NEW_DEFAULT_CATEGORY(s4u_energyptask, "Messages specific for this s4u example");
28 /* Retrieve the list of all hosts as an array of hosts */
29 std::vector<simgrid::s4u::Host*> hosts = simgrid::s4u::Engine::get_instance()->get_all_hosts();
30 int hosts_count = hosts.size();
32 XBT_INFO("First, build a classical parallel task, with 1 Gflop to execute on each node, "
33 "and 10MB to exchange between each pair");
35 std::vector<double> computation_amounts;
36 std::vector<double> communication_amounts;
38 /* ------[ test 1 ]----------------- */
39 computation_amounts.assign(hosts.size(), 1e9 /*1Gflop*/);
40 communication_amounts.assign(hosts.size() * hosts.size(), 0);
41 for (int i = 0; i < hosts_count; i++)
42 for (int j = i + 1; j < hosts_count; j++)
43 communication_amounts[i * hosts_count + j] = 1e7; // 10 MB
45 simgrid::s4u::this_actor::parallel_execute(hosts, computation_amounts, communication_amounts);
47 /* ------[ test 2 ]----------------- */
48 XBT_INFO("We can do the same with a timeout of one second enabled.");
49 computation_amounts.assign(hosts.size(), 1e9 /*1Gflop*/);
50 communication_amounts.assign(hosts.size() * hosts.size(), 0);
51 for (int i = 0; i < hosts_count; i++)
52 for (int j = i + 1; j < hosts_count; j++)
53 communication_amounts[i * hosts_count + j] = 1e7; // 10 MB
56 simgrid::s4u::this_actor::parallel_execute(hosts, computation_amounts, communication_amounts,
57 1.0 /* timeout (in seconds)*/);
58 XBT_WARN("Woops, this did not timeout as expected... Please report that bug.");
60 /* Do nothing this exception on timeout was expected */
61 XBT_DEBUG("Caught expected exception: %s", e.what());
64 /* ------[ test 3 ]----------------- */
65 XBT_INFO("Then, build a parallel task involving only computations and no communication (1 Gflop per node)");
66 computation_amounts.assign(hosts.size(), 1e9 /*1Gflop*/);
67 communication_amounts.clear(); /* no comm */
68 simgrid::s4u::this_actor::parallel_execute(hosts, computation_amounts, communication_amounts);
70 /* ------[ test 4 ]----------------- */
71 XBT_INFO("Then, build a parallel task involving only heterogeneous computations and no communication");
72 computation_amounts.resize(hosts.size());
73 for (int i = 0; i < hosts_count; i++)
74 computation_amounts[i] = 5 * (i + 1) * 1e8; // 500Mflop, 1Gflop, 1.5Gflop
75 communication_amounts.clear(); /* no comm */
76 simgrid::s4u::this_actor::parallel_execute(hosts, computation_amounts, communication_amounts);
78 /* ------[ test 5 ]----------------- */
79 XBT_INFO("Then, build a parallel task with no computation nor communication (synchro only)");
80 computation_amounts.clear();
81 communication_amounts.clear();
82 simgrid::s4u::this_actor::parallel_execute(hosts, computation_amounts, communication_amounts);
84 /* ------[ test 6 ]----------------- */
85 XBT_INFO("Finally, trick the ptask to do a 'remote execution', on host %s", hosts[1]->get_cname());
86 std::vector<simgrid::s4u::Host*> remote;
87 remote.push_back(hosts[1]);
88 computation_amounts.assign(1, 1e9);
89 communication_amounts.clear();
91 simgrid::s4u::this_actor::parallel_execute(remote, computation_amounts, communication_amounts);
93 XBT_INFO("Goodbye now!");
96 int main(int argc, char* argv[])
98 simgrid::s4u::Engine e(&argc, argv);
100 xbt_assert(argc <= 3, "1Usage: %s <platform file> [--energy]", argv[0]);
101 xbt_assert(argc >= 2, "2Usage: %s <platform file> [--energy]", argv[0]);
103 if (argc == 3 && argv[2][2] == 'e')
104 sg_host_energy_plugin_init();
106 e.load_platform(argv[1]);
108 /* Pick a process, no matter which, from the platform file */
109 simgrid::s4u::Actor::create("test", simgrid::s4u::Host::by_name("MyHost1"), runner);
112 XBT_INFO("Simulation done.");