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"
14 #include "gras_config.h"
16 XBT_LOG_NEW_DEFAULT_SUBCATEGORY(simix_context, simix,
17 "Context switching mecanism");
19 char* smx_context_factory_name = NULL; /* factory name specified by --cfg=contexts/factory:value */
20 smx_ctx_factory_initializer_t smx_factory_initializer_to_use = NULL;
21 int smx_context_stack_size = 128 * 1024;
23 #ifdef CONTEXT_THREADS
24 __thread smx_context_t smx_current_context;
26 smx_context_t smx_current_context;
29 static int smx_parallel_contexts = 1;
32 * This function is called by SIMIX_global_init() to initialize the context module.
34 void SIMIX_context_mod_init(void)
36 if (!simix_global->context_factory) {
37 /* select the context factory to use to create the contexts */
38 if (smx_factory_initializer_to_use) {
39 (*smx_factory_initializer_to_use)(&(simix_global->context_factory));
41 else { /* use the factory specified by --cfg=contexts/factory:value */
42 if (smx_context_factory_name == NULL || !strcmp(smx_context_factory_name, "ucontext")) {
44 SIMIX_ctx_sysv_factory_init(&simix_global->context_factory);
46 else if (!strcmp(smx_context_factory_name, "thread")) {
47 /* use os threads (either pthreads or windows ones) */
48 SIMIX_ctx_thread_factory_init(&simix_global->context_factory);
50 else if (!strcmp(smx_context_factory_name, "raw")) {
51 /* use raw contexts */
52 SIMIX_ctx_raw_factory_init(&simix_global->context_factory);
55 xbt_die("Invalid context factory specified");
62 * This function is call by SIMIX_clean() to finalize the context module.
64 void SIMIX_context_mod_exit(void)
66 if (simix_global->context_factory) {
67 smx_pfn_context_factory_finalize_t finalize_factory;
69 /* finalize the context factory */
70 finalize_factory = simix_global->context_factory->finalize;
71 (*finalize_factory) (&simix_global->context_factory);
73 xbt_dict_remove((xbt_dict_t) _surf_cfg_set,"contexts/factory");
77 * \brief Sets the number of parallel threads to use
78 * for the user contexts.
80 * This function should be called before initializing SIMIX.
81 * A value of 1 means no parallelism.
82 * If the value is greater than 1, the thread support must be enabled.
84 * \param nb_threads the number of threads to use
86 void SIMIX_context_set_nthreads(int nb_threads) {
88 xbt_assert1(nb_threads > 0, "Invalid number of parallel threads: %d", nb_threads);
89 smx_parallel_contexts = nb_threads;
93 * \brief Returns the number of parallel threads used
94 * for the user contexts.
95 * \return the number of threads (1 means no parallelism)
97 int SIMIX_context_get_nthreads() {
98 return smx_parallel_contexts;
102 * \brief Returns whether some parallel threads are used
103 * for the user contexts.
104 * \return 1 if parallelism is used
106 int SIMIX_context_is_parallel() {
107 return smx_parallel_contexts > 1;