X-Git-Url: http://info.iut-bm.univ-fcomte.fr/pub/gitweb/simgrid.git/blobdiff_plain/056593992509f32c834360664489e8e239d22802..ab6dbae7f0ae8ebd519f86898d23e909f5f57b56:/src/simix/smx_context.c

diff --git a/src/simix/smx_context.c b/src/simix/smx_context.c
index 7e0b7e56c7..fed8f7fe3f 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
@@ -22,12 +22,11 @@ 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;
 
@@ -39,7 +38,7 @@ 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 */
 
@@ -104,11 +103,29 @@ 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.
@@ -125,7 +142,7 @@ XBT_INLINE void SIMIX_context_set_nthreads(int 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
   }
 
@@ -133,21 +150,16 @@ XBT_INLINE void SIMIX_context_set_nthreads(int 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 +176,48 @@ 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) {
+  e_xbt_parmap_mode_t mode = XBT_PARMAP_FUTEX;
+  const char* mode_name = xbt_cfg_get_string(_surf_cfg_set, "contexts/synchro");
+  if (!strcmp(mode_name, "posix")) {
+	  mode = XBT_PARMAP_POSIX;
+  }
+  else if (!strcmp(mode_name, "futex")) {
+	  mode = XBT_PARMAP_FUTEX;
+  }
+  else if (!strcmp(mode_name, "busy_wait")) {
+	  mode = XBT_PARMAP_BUSY_WAIT;
+  }
+  else {
+    XBT_WARN("Command line setting of the parallel synchronization mode should "
+        "be one of \"posix\", \"futex\" or \"busy_wait\"");
+  }
+  return 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) {
+  if (mode == XBT_PARMAP_POSIX) {
+	  xbt_cfg_set_string(_surf_cfg_set, "contexts/synchro", "posix");
+  }
+  else if (mode == XBT_PARMAP_FUTEX) {
+	  xbt_cfg_set_string(_surf_cfg_set, "contexts/synchro", "futex");
+  }
+  else if (XBT_PARMAP_BUSY_WAIT) {
+	  xbt_cfg_set_string(_surf_cfg_set, "contexts/synchro", "busy_wait");
+  }
+  else {
+    XBT_WARN("Command line setting of the parallel synchronization mode should "
+        "be one of \"posix\", \"futex\" or \"busy_wait\"");
+  }
 }
 
 /**
@@ -182,11 +226,16 @@ 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 +244,15 @@ 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;
+  }
 }