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. */
8 #include "simgrid/msg.h" /* Yeah! If you want to use msg, you need to include simgrid/msg.h */
9 #include "xbt/sysdep.h" /* calloc, printf */
11 /* Create a log channel to have nice outputs. */
13 #include "xbt/asserts.h"
14 XBT_LOG_NEW_DEFAULT_CATEGORY(msg_test,
15 "Messages specific for this msg example");
17 /** @addtogroup MSG_examples
19 * - <b>parallel_task/parallel_task.c</b>: Demonstrates the use of
20 * @ref MSG_parallel_task_create, to create special tasks that run
21 * on several hosts at the same time. The resulting simulations are
22 * very close to what can be achieved in @ref SD_API, but still
23 * allows to use the other features of MSG (it'd be cool to be able
24 * to mix interfaces, but it's not possible ATM).
28 /** Function in charge of running the example (that's a simgrid process) */
29 static int runner(int argc, char *argv[])
33 /* Retrieve the list of all hosts as an array of hosts */
34 xbt_dynar_t slaves_dynar = MSG_hosts_as_dynar();
35 int slaves_count = xbt_dynar_length(slaves_dynar);
36 msg_host_t *slaves = xbt_dynar_to_array(slaves_dynar);
38 XBT_INFO("First, build a classical parallel task, with 1 Gflop to execute on each node, and 10MB to exchange between each pair");
39 double *computation_amounts = xbt_new0(double, slaves_count);
40 double *communication_amounts = xbt_new0(double, slaves_count * slaves_count);
42 for (i = 0; i < slaves_count; i++)
43 computation_amounts[i] = 1e9; // 1 Gflop
45 for (i = 0; i < slaves_count; i++)
46 for (j = i + 1; j < slaves_count; j++)
47 communication_amounts[i * slaves_count + j] = 1e7; // 10 MB
49 msg_task_t ptask = MSG_parallel_task_create("parallel task",
50 slaves_count, slaves, computation_amounts, communication_amounts, NULL /* no specific data to attach */);
51 MSG_parallel_task_execute(ptask);
52 MSG_task_destroy(ptask);
53 /* The arrays communication_amounts and computation_amounts are not to be freed manually */
55 XBT_INFO("Then, build a parallel task involving only computations and no communication (1 Gflop per node)");
56 computation_amounts = xbt_new0(double, slaves_count);
57 for (i = 0; i < slaves_count; i++)
58 computation_amounts[i] = 1e9; // 1 Gflop
59 ptask = MSG_parallel_task_create("parallel exec", slaves_count, slaves, computation_amounts, NULL/* no comm */, NULL /* no data */);
60 MSG_parallel_task_execute(ptask);
61 MSG_task_destroy(ptask);
63 XBT_INFO("Finally, trick the ptask to do a 'remote execution', on host %s", MSG_host_get_name(slaves[1]));
64 computation_amounts = xbt_new0(double, 1);
65 computation_amounts[0] = 1e9; // 1 Gflop
66 msg_host_t *remote = xbt_new(msg_host_t,1);
67 remote[0] = slaves[1];
68 ptask = MSG_parallel_task_create("remote exec", 1, remote, computation_amounts, NULL/* no comm */, NULL /* no data */);
69 MSG_parallel_task_execute(ptask);
70 MSG_task_destroy(ptask);
73 XBT_INFO("Goodbye now!");
78 int main(int argc, char *argv[])
80 MSG_init(&argc, argv);
81 MSG_config("host/model", "ptask_L07");
83 xbt_assert(argc > 1, "Usage: %s <platform file>", argv[0]);
84 MSG_create_environment(argv[1]);
86 /* Pick a process, no matter which, from the platform file */
87 xbt_dynar_t all_hosts = MSG_hosts_as_dynar();
88 msg_host_t first_host = xbt_dynar_getfirst_as(all_hosts,msg_host_t);
89 xbt_dynar_free(&all_hosts);
91 MSG_process_create("test", runner, NULL, first_host);
92 msg_error_t res = MSG_main();
93 XBT_INFO("Simulation done.");