1 /* a fast and simple context switching library */
3 /* Copyright (c) 2009, 2010. The SimGrid Team.
4 * All rights reserved. */
6 /* This program is free software; you can redistribute it and/or modify it
7 * under the terms of the license (GNU LGPL) which comes with this package. */
13 #include "simix/context.h"
15 XBT_LOG_NEW_DEFAULT_SUBCATEGORY(simix_context, simix,
16 "Context switching mecanism");
18 char* smx_context_factory_name = NULL; /* factory name specified by --cfg=contexts/factory:value */
19 smx_ctx_factory_initializer_t smx_factory_initializer_to_use = NULL;
20 int smx_context_stack_size = 128 * 1024;
21 smx_context_t smx_current_context;
22 static int smx_parallel_contexts;
25 * This function is called by SIMIX_global_init() to initialize the context module.
27 void SIMIX_context_mod_init(void)
29 if (!simix_global->context_factory) {
30 /* select the context factory to use to create the contexts */
31 if (smx_factory_initializer_to_use) {
32 (*smx_factory_initializer_to_use)(&(simix_global->context_factory));
34 else { /* use the factory specified by --cfg=contexts/factory:value */
35 if (smx_context_factory_name == NULL || !strcmp(smx_context_factory_name, "ucontext")) {
37 SIMIX_ctx_sysv_factory_init(&simix_global->context_factory);
39 else if (!strcmp(smx_context_factory_name, "thread")) {
40 /* use os threads (either pthreads or windows ones) */
41 SIMIX_ctx_thread_factory_init(&simix_global->context_factory);
43 else if (!strcmp(smx_context_factory_name, "raw")) {
44 /* use raw contexts */
45 SIMIX_ctx_raw_factory_init(&simix_global->context_factory);
48 xbt_die("Invalid context factory specified");
55 * This function is call by SIMIX_clean() to finalize the context module.
57 void SIMIX_context_mod_exit(void)
59 if (simix_global->context_factory) {
60 smx_pfn_context_factory_finalize_t finalize_factory;
62 /* finalize the context factory */
63 finalize_factory = simix_global->context_factory->finalize;
64 (*finalize_factory) (&simix_global->context_factory);
66 xbt_dict_remove((xbt_dict_t) _surf_cfg_set,"contexts/factory");
70 * \brief Sets the number of parallel threads to use
71 * for the user contexts.
73 * This function should be called before initializing SIMIX.
74 * A value of 1 means no parallelism.
75 * If the value is greater than 1, the thread support must be enabled.
77 * \param nb_threads the number of threads to use
79 void SIMIX_context_set_parallel_threads(int nb_threads) {
81 xbt_assert1(nb_threads > 0, "Invalid number of parallel threads: %d", nb_threads);
82 smx_parallel_contexts = nb_threads;
86 * \brief Returns the number of parallel threads used
87 * for the user contexts.
88 * \return the number of threads (1 means no parallelism)
90 int SIMIX_context_get_parallel_threads() {
91 return smx_parallel_contexts;
95 * \brief Returns whether some parallel threads are used
96 * for the user contexts.
97 * \return 1 if parallelism is used
99 int SIMIX_context_is_parallel() {
100 return smx_parallel_contexts > 1;