X-Git-Url: http://info.iut-bm.univ-fcomte.fr/pub/gitweb/simgrid.git/blobdiff_plain/bee3400ba6e1daeca869db8753dc4d86bcda28ca..23f5bf52cc58cf837840f231cf638e9fcd45097b:/src/simix/smx_context.c

diff --git a/src/simix/smx_context.c b/src/simix/smx_context.c
index ec51170f05..9e1a961f35 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
@@ -10,26 +10,25 @@
 #include "xbt/log.h"
 #include "xbt/swag.h"
 #include "xbt/xbt_os_thread.h"
-#include "src/simix/private.h"
-#include "simix/context.h"
+#include "smx_private.h"
 #include "gras_config.h"
 
 XBT_LOG_NEW_DEFAULT_SUBCATEGORY(simix_context, simix,
-                                "Context switching mecanism");
+                                "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;
 
 #ifdef HAVE_THREAD_LOCAL_STORAGE
-__thread smx_context_t smx_current_context;
+static __thread smx_context_t smx_current_context_parallel;
 #else
-smx_context_t smx_current_context; /* define it anyway, will be used in non-parallel mode */
 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.
@@ -45,13 +44,13 @@ void SIMIX_context_mod_init(void)
 
     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
+  #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 if (!strcmp(smx_context_factory_name, "ucontext")) {
         /* use ucontext */
@@ -62,12 +61,12 @@ void SIMIX_context_mod_init(void)
 #endif
       }
       else if (!strcmp(smx_context_factory_name, "thread")) {
-	/* use os threads (either pthreads or windows ones) */
+  /* use os threads (either pthreads or windows ones) */
         SIMIX_ctx_thread_factory_init(&simix_global->context_factory);
       }
       else if (!strcmp(smx_context_factory_name, "raw")) {
-	/* use raw contexts */
-	SIMIX_ctx_raw_factory_init(&simix_global->context_factory);
+  /* use raw contexts */
+  SIMIX_ctx_raw_factory_init(&simix_global->context_factory);
       }
       else {
         XBT_ERROR("Invalid context factory specified. Valid factories on this machine:");
@@ -109,45 +108,61 @@ void SIMIX_context_mod_exit(void)
   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.
+ * 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<=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, "No thread support for parallel context execution");
+    THROWF(arg_error, 0, "The thread factory cannot be run in parallel");
 #endif
   }
-
+ 
   smx_parallel_contexts = nb_threads;
 }
 
 /**
- * \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 Returns whether some parallel threads are used
- * for the user contexts.
- * \return 1 if parallelism is used
+ * \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_is_parallel(void) {
-  return smx_parallel_contexts > 1;
+XBT_INLINE int SIMIX_context_get_parallel_threshold(void) {
+  return smx_parallel_threshold;
 }
 
 /**
@@ -164,16 +179,21 @@ XBT_INLINE void SIMIX_context_set_parallel_threshold(int threshold) {
 }
 
 /**
- * \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
+ * \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 int SIMIX_context_get_parallel_threshold(void) {
-  return smx_parallel_threshold;
+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;
 }
 
 /**
@@ -182,11 +202,16 @@ XBT_INLINE int SIMIX_context_get_parallel_threshold(void) {
  */
 XBT_INLINE smx_context_t SIMIX_context_get_current(void)
 {
+  if (SIMIX_context_is_parallel()) {
 #ifdef HAVE_THREAD_LOCAL_STORAGE
-  return smx_current_context;
+    return smx_current_context_parallel;
 #else
-  return xbt_os_thread_get_specific(smx_current_context_key);
+    return xbt_os_thread_get_specific(smx_current_context_key);
 #endif
+  }
+  else {
+    return smx_current_context_serial;
+  }
 }
 
 /**
@@ -195,10 +220,15 @@ XBT_INLINE smx_context_t SIMIX_context_get_current(void)
  */
 XBT_INLINE void SIMIX_context_set_current(smx_context_t context)
 {
+  if (SIMIX_context_is_parallel()) {
 #ifdef HAVE_THREAD_LOCAL_STORAGE
-  smx_current_context = context;
+    smx_current_context_parallel = context;
 #else
-  xbt_os_thread_set_specific(smx_current_context_key, context);
+    xbt_os_thread_set_specific(smx_current_context_key, context);
 #endif
+  }
+  else {
+    smx_current_context_serial = context;
+  }
 }