/* a fast and simple context switching library */
-/* Copyright (c) 2009, 2010. The SimGrid Team.
+/* Copyright (c) 2009-2013. The SimGrid Team.
* All rights reserved. */
/* This program is free software; you can redistribute it and/or modify it
#include "portable.h"
#include "xbt/log.h"
#include "xbt/swag.h"
-#include "private.h"
+#include "xbt/xbt_os_thread.h"
+#include "smx_private.h"
+#include "simgrid/sg_config.h"
+#include "internal_config.h"
XBT_LOG_NEW_DEFAULT_SUBCATEGORY(simix_context, simix,
- "Context switching mecanism");
-
-const char *xbt_ctx_factory_to_use = NULL;
-typedef void (*SIMIX_ctx_factory_initializer_t)(smx_context_factory_t *);
-SIMIX_ctx_factory_initializer_t factory_initializer_to_use = NULL;
+ "Context switching mechanism");
+
+char* smx_context_factory_name = NULL; /* factory name specified by --cfg=contexts/factory:value */
+smx_ctx_factory_initializer_t smx_factory_initializer_to_use = NULL;
+int smx_context_stack_size = 128 * 1024;
+int smx_context_stack_size_was_set = 0;
+#ifdef HAVE_THREAD_LOCAL_STORAGE
+static __thread smx_context_t smx_current_context_parallel;
+#else
+static xbt_os_thread_key_t smx_current_context_key = 0;
+#endif
+static smx_context_t smx_current_context_serial;
+static int smx_parallel_contexts = 1;
+static int smx_parallel_threshold = 2;
+static e_xbt_parmap_mode_t smx_parallel_synchronization_mode = XBT_PARMAP_DEFAULT;
/**
* This function is called by SIMIX_global_init() to initialize the context module.
*/
void SIMIX_context_mod_init(void)
{
+#if defined(CONTEXT_THREADS) && !defined(HAVE_THREAD_LOCAL_STORAGE)
+ /* the __thread storage class is not available on this platform:
+ * use getspecific/setspecific instead to store the current context in each thread */
+ xbt_os_thread_key_create(&smx_current_context_key);
+#endif
if (!simix_global->context_factory) {
- /* select context factory to use to create the context(depends of the macro definitions) */
- if (factory_initializer_to_use) {
- (*factory_initializer_to_use)(&(simix_global->context_factory));
- } else {
-#ifdef CONTEXT_THREADS /* Use os threads (either pthreads or windows ones) */
- SIMIX_ctx_thread_factory_init(&simix_global->context_factory);
-#elif defined(CONTEXT_UCONTEXT) /* use ucontext */
- SIMIX_ctx_sysv_factory_init(&simix_global->context_factory);
+ /* select the context factory to use to create the contexts */
+ if (smx_factory_initializer_to_use) {
+ smx_factory_initializer_to_use(&simix_global->context_factory);
+ }
+ else { /* use the factory specified by --cfg=contexts/factory:value */
+
+
+ if (!strcmp(smx_context_factory_name, "thread")) {
+ /* use os threads (either pthreads or windows ones) */
+ SIMIX_ctx_thread_factory_init(&simix_global->context_factory);
+ }
+#ifdef CONTEXT_UCONTEXT
+ else if (!strcmp(smx_context_factory_name, "ucontext")) {
+ /* use ucontext */
+ SIMIX_ctx_sysv_factory_init(&simix_global->context_factory);
+ }
+#endif
+#ifdef HAVE_RAWCTX
+ else if (!strcmp(smx_context_factory_name, "raw")) {
+ /* use raw contexts */
+ SIMIX_ctx_raw_factory_init(&simix_global->context_factory);
+ }
+#endif
+ else {
+ XBT_ERROR("Invalid context factory specified. Valid factories on this machine:");
+#ifdef HAVE_RAWCTX
+ XBT_ERROR(" raw: high performance context factory implemented specifically for SimGrid");
#else
-#error ERROR [__FILE__, line __LINE__]: no context implementation specified.
+ XBT_ERROR(" (raw contexts are disabled at compilation time on this machine -- check configure logs for details)");
#endif
+#ifdef CONTEXT_UCONTEXT
+ XBT_ERROR(" ucontext: classical system V contexts (implemented with makecontext, swapcontext and friends)");
+#else
+ XBT_ERROR(" (ucontext is disabled at compilation time on this machine -- check configure logs for details)");
+#endif
+ XBT_ERROR(" thread: slow portability layer using system threads (pthreads on UNIX, CreateThread() on windows)");
+ xbt_die("Please use a valid factory.");
+ }
}
}
}
/**
- * This function is call by SIMIX_clean() to finalize the context module.
+ * This function is called by SIMIX_clean() to finalize the context module.
*/
void SIMIX_context_mod_exit(void)
{
/* finalize the context factory */
finalize_factory = simix_global->context_factory->finalize;
- (*finalize_factory) (&simix_global->context_factory);
+ finalize_factory(&simix_global->context_factory);
}
+ xbt_dict_remove((xbt_dict_t) _sg_cfg_set,"contexts/factory");
}
/**
- * This function is used to change the context factory.
- * Warning: it destroy all the existing processes (even for maestro), and it
- * will create a new maestro process using the new context factory.
+ * \brief Returns whether some parallel threads are used
+ * for the user contexts.
+ * \return 1 if parallelism is used
*/
-int SIMIX_context_select_factory(const char *name)
-{
- /* if a context factory is already instantiated and it is different from the
- newly selected one, then kill all the processes, exit the context module
- and initialize the new factory.
- */
+XBT_INLINE int SIMIX_context_is_parallel(void) {
+ return smx_parallel_contexts > 1;
+}
+/**
+ * \brief Returns the number of parallel threads used
+ * for the user contexts.
+ * \return the number of threads (1 means no parallelism)
+ */
+XBT_INLINE int SIMIX_context_get_nthreads(void) {
+ return smx_parallel_contexts;
+}
- if (simix_global->context_factory != NULL) {
- if (strcmp(simix_global->context_factory->name, name)) {
+/**
+ * \brief Sets the number of parallel threads to use
+ * for the user contexts.
+ *
+ * This function should be called before initializing SIMIX.
+ * A value of 1 means no parallelism (1 thread only).
+ * If the value is greater than 1, the thread support must be enabled.
+ *
+ * \param nb_threads the number of threads to use
+ */
+void SIMIX_context_set_nthreads(int nb_threads) {
+ if (nb_threads<=0) {
+ nb_threads = xbt_os_get_numcores();
+ XBT_INFO("Auto-setting contexts/nthreads to %d",nb_threads);
+ }
+
+ if (nb_threads > 1) {
+#ifndef CONTEXT_THREADS
+ THROWF(arg_error, 0, "The thread factory cannot be run in parallel");
+#endif
+ }
+ smx_parallel_contexts = nb_threads;
+}
- SIMIX_process_killall();
+/**
+ * \brief Returns the threshold above which user processes are run in parallel.
+ *
+ * If the number of threads is set to 1, there is no parallelism and this
+ * threshold has no effect.
+ *
+ * \return when the number of user processes ready to run is above
+ * this threshold, they are run in parallel
+ */
+XBT_INLINE int SIMIX_context_get_parallel_threshold(void) {
+ return smx_parallel_threshold;
+}
- /* kill maestro process */
- SIMIX_context_free(simix_global->maestro_process->context);
- free(simix_global->maestro_process);
- simix_global->maestro_process = NULL;
+/**
+ * \brief Sets the threshold above which user processes are run in parallel.
+ *
+ * If the number of threads is set to 1, there is no parallelism and this
+ * threshold has no effect.
+ *
+ * \param threshold when the number of user processes ready to run is above
+ * this threshold, they are run in parallel
+ */
+XBT_INLINE void SIMIX_context_set_parallel_threshold(int threshold) {
+ smx_parallel_threshold = threshold;
+}
- SIMIX_context_mod_exit();
- } else
- /* the same context factory is requested return directly */
- return 0;
- }
+/**
+ * \brief Returns the synchronization mode used when processes are run in
+ * parallel.
+ * \return how threads are synchronized if processes are run in parallel
+ */
+XBT_INLINE e_xbt_parmap_mode_t SIMIX_context_get_parallel_mode(void) {
+ return smx_parallel_synchronization_mode;
+}
- /* init the desired factory */
- smx_context_factory_t * factory = &simix_global->context_factory;
- if (!strcmp(name, "java"))
-#ifdef HAVE_JAVA
- SIMIX_ctx_java_factory_init(factory);
-#else
- THROW0(not_found_error, 0,
- "Factory 'Java' does not exist: Java support was not compiled in the SimGrid library");
-#endif /* HAVE_JAVA */
+/**
+ * \brief Sets the synchronization mode to use when processes are run in
+ * parallel.
+ * \param mode how to synchronize threads if processes are run in parallel
+ */
+XBT_INLINE void SIMIX_context_set_parallel_mode(e_xbt_parmap_mode_t mode) {
+ smx_parallel_synchronization_mode = mode;
+}
- else if (!strcmp(name, "thread"))
-#ifdef CONTEXT_THREADS
- SIMIX_ctx_thread_factory_init(factory);
+/**
+ * \brief Returns the current context of this thread.
+ * \return the current context of this thread
+ */
+XBT_INLINE smx_context_t SIMIX_context_get_current(void)
+{
+ if (SIMIX_context_is_parallel()) {
+#ifdef HAVE_THREAD_LOCAL_STORAGE
+ return smx_current_context_parallel;
#else
- THROW0(not_found_error, 0,
- "Factory 'thread' does not exist: thread support was not compiled in the SimGrid library");
-#endif /* CONTEXT_THREADS */
+ return xbt_os_thread_get_specific(smx_current_context_key);
+#endif
+ }
+ else {
+ return smx_current_context_serial;
+ }
+}
- else if (!strcmp(name, "sysv"))
-#if !defined(_XBT_WIN32) && !defined(CONTEXT_THREADS)
- SIMIX_ctx_sysv_factory_init(factory);
+/**
+ * \brief Sets the current context of this thread.
+ * \param context the context to set
+ */
+XBT_INLINE void SIMIX_context_set_current(smx_context_t context)
+{
+ if (SIMIX_context_is_parallel()) {
+#ifdef HAVE_THREAD_LOCAL_STORAGE
+ smx_current_context_parallel = context;
#else
- THROW0(not_found_error, 0,
- "Factory 'sysv' does not exist: no System V thread support under Windows");
+ xbt_os_thread_set_specific(smx_current_context_key, context);
#endif
-
- else
- THROW1(not_found_error, 0, "Factory '%s' does not exist", name);
-
-
-
-
- SIMIX_create_maestro_process();
-
- return 0;
+ }
+ else {
+ smx_current_context_serial = context;
+ }
}
-
