1 /* Copyright (c) 2007-2015. 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 #include "simgrid/msg.h"
9 XBT_LOG_NEW_DEFAULT_CATEGORY(msg_test, "Messages specific for this msg example");
11 /** @addtogroup MSG_examples
13 * - <b>parallel_task/parallel_task.c</b>: Demonstrates the use of @ref MSG_parallel_task_create, to create special
14 * tasks that run on several hosts at the same time. The resulting simulations are very close to what can be
15 * achieved in @ref SD_API, but still allows to use the other features of MSG (it'd be cool to be able to mix
16 * interfaces, but it's not possible ATM).
19 static int runner(int argc, char *argv[])
21 /* Retrieve the list of all hosts as an array of hosts */
22 xbt_dynar_t slaves_dynar = MSG_hosts_as_dynar();
23 int slaves_count = xbt_dynar_length(slaves_dynar);
24 msg_host_t *slaves = xbt_dynar_to_array(slaves_dynar);
26 XBT_INFO("First, build a classical parallel task, with 1 Gflop to execute on each node, "
27 "and 10MB to exchange between each pair");
28 double *computation_amounts = xbt_new0(double, slaves_count);
29 double *communication_amounts = xbt_new0(double, slaves_count * slaves_count);
31 for (int i = 0; i < slaves_count; i++)
32 computation_amounts[i] = 1e9; // 1 Gflop
34 for (int i = 0; i < slaves_count; i++)
35 for (int j = i + 1; j < slaves_count; j++)
36 communication_amounts[i * slaves_count + j] = 1e7; // 10 MB
39 MSG_parallel_task_create("parallel task", slaves_count, slaves, computation_amounts, communication_amounts, NULL);
40 MSG_parallel_task_execute(ptask);
41 MSG_task_destroy(ptask);
42 /* The arrays communication_amounts and computation_amounts are not to be freed manually */
44 XBT_INFO("Then, build a parallel task involving only computations and no communication (1 Gflop per node)");
45 computation_amounts = xbt_new0(double, slaves_count);
46 for (int i = 0; i < slaves_count; i++)
47 computation_amounts[i] = 1e9; // 1 Gflop
49 MSG_parallel_task_create("parallel exec", slaves_count, slaves, computation_amounts, NULL/* no comm */, NULL);
50 MSG_parallel_task_execute(ptask);
51 MSG_task_destroy(ptask);
53 XBT_INFO("Finally, trick the ptask to do a 'remote execution', on host %s", MSG_host_get_name(slaves[1]));
54 computation_amounts = xbt_new0(double, 1);
55 computation_amounts[0] = 1e9; // 1 Gflop
56 msg_host_t *remote = xbt_new(msg_host_t,1);
57 remote[0] = slaves[1];
58 ptask = MSG_parallel_task_create("remote exec", 1, remote, computation_amounts, NULL/* no comm */, NULL);
59 MSG_parallel_task_execute(ptask);
60 MSG_task_destroy(ptask);
63 XBT_INFO("Goodbye now!");
68 int main(int argc, char *argv[])
70 MSG_init(&argc, argv);
71 MSG_config("host/model", "ptask_L07");
73 xbt_assert(argc > 1, "Usage: %s <platform file>", argv[0]);
74 MSG_create_environment(argv[1]);
76 /* Pick a process, no matter which, from the platform file */
77 xbt_dynar_t all_hosts = MSG_hosts_as_dynar();
78 msg_host_t first_host = xbt_dynar_getfirst_as(all_hosts,msg_host_t);
79 xbt_dynar_free(&all_hosts);
81 MSG_process_create("test", runner, NULL, first_host);
82 msg_error_t res = MSG_main();
83 XBT_INFO("Simulation done.");