X-Git-Url: http://info.iut-bm.univ-fcomte.fr/pub/gitweb/simgrid.git/blobdiff_plain/8a24d575ab0a1d565521896081c6d5e0f1dfb941..7631e98c4699e3d1f9fa92a21594294f119f95ac:/src/simix/smx_context.c diff --git a/src/simix/smx_context.c b/src/simix/smx_context.c index 1044a01ec2..9faef0ed17 100644 --- a/src/simix/smx_context.c +++ b/src/simix/smx_context.c @@ -1,6 +1,6 @@ /* a fast and simple context switching library */ -/* Copyright (c) 2009, 2010. The SimGrid Team. +/* Copyright (c) 2009 - 2011. The SimGrid Team. * All rights reserved. */ /* This program is free software; you can redistribute it and/or modify it @@ -9,15 +9,27 @@ #include "portable.h" #include "xbt/log.h" #include "xbt/swag.h" -#include "private.h" +#include "xbt/xbt_os_thread.h" +#include "src/simix/private.h" #include "simix/context.h" +#include "gras_config.h" XBT_LOG_NEW_DEFAULT_SUBCATEGORY(simix_context, simix, "Context switching mecanism"); -char* smx_context_factory_name = NULL; /* factory name specified by --cfg=simix/context=value */ +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; -smx_context_t smx_current_context; +int smx_context_stack_size = 128 * 1024; + +#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_FUTEX; /** * This function is called by SIMIX_global_init() to initialize the context module. @@ -27,12 +39,27 @@ void SIMIX_context_mod_init(void) if (!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)); + smx_factory_initializer_to_use(&simix_global->context_factory); + } + else { /* use the factory specified by --cfg=contexts/factory:value */ + + if (smx_context_factory_name == NULL) { + /* use the default factory */ + #ifdef HAVE_RAWCTX + SIMIX_ctx_raw_factory_init(&simix_global->context_factory); + #elif CONTEXT_UCONTEXT + SIMIX_ctx_sysv_factory_init(&simix_global->context_factory); + #else + SIMIX_ctx_thread_factory_init(&simix_global->context_factory); + #endif } - else { /* use the factory specified by --cfg=simix/ctx:value */ - if (smx_context_factory_name == NULL || !strcmp(smx_context_factory_name, "ucontext")) { + else if (!strcmp(smx_context_factory_name, "ucontext")) { /* use ucontext */ +#ifdef CONTEXT_UCONTEXT SIMIX_ctx_sysv_factory_init(&simix_global->context_factory); +#else + xbt_die("The context factory 'ucontext' unavailable on your system"); +#endif } else if (!strcmp(smx_context_factory_name, "thread")) { /* use os threads (either pthreads or windows ones) */ @@ -43,10 +70,28 @@ void SIMIX_context_mod_init(void) SIMIX_ctx_raw_factory_init(&simix_global->context_factory); } else { - xbt_die("Invalid context factory specified"); + 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 + XBT_ERROR(" (raw contextes are disabled at compilation time on this machine -- check configure logs for details)"); +#endif +#ifdef CONTEXT_UCONTEXT + XBT_ERROR(" ucontext: classical system V contextes (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."); } } } + +#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 } /** @@ -59,7 +104,129 @@ 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) _surf_cfg_set,"contexts/factory"); +} + +/** + * \brief Returns whether some parallel threads are used + * for the user contexts. + * \return 1 if parallelism is used + */ +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; +} + +/** + * \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 + */ +XBT_INLINE void SIMIX_context_set_nthreads(int nb_threads) { + + xbt_assert(nb_threads > 0, "Invalid number of parallel threads: %d", nb_threads); + + if (nb_threads > 1) { +#ifndef CONTEXT_THREADS + THROWF(arg_error, 0, "The thread factory cannot be run in parallel"); +#endif } - xbt_dict_remove((xbt_dict_t) _surf_cfg_set,"simix/context"); + + smx_parallel_contexts = nb_threads; } + +/** + * \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; +} + +/** + * \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; +} + +/** + * \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; +} + +/** + * \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; +} + +/** + * \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 + return xbt_os_thread_get_specific(smx_current_context_key); +#endif + } + else { + return smx_current_context_serial; + } +} + +/** + * \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 + xbt_os_thread_set_specific(smx_current_context_key, context); +#endif + } + else { + smx_current_context_serial = context; + } +} +