X-Git-Url: http://info.iut-bm.univ-fcomte.fr/pub/gitweb/simgrid.git/blobdiff_plain/dbfa5606c9912e09908b3343ec7a56b283ec82b9..5880a1bbbf150def1664cfefd6ec7f36f56edfaa:/src/simix/smx_context.c

diff --git a/src/simix/smx_context.c b/src/simix/smx_context.c
index 2da152b007..12552da99c 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) 2009-2014. The SimGrid Team.
  * All rights reserved.                                                     */
 
 /* This program is free software; you can redistribute it and/or modify it
@@ -9,57 +9,83 @@
 #include "portable.h"
 #include "xbt/log.h"
 #include "xbt/swag.h"
-#include "private.h"
-#include "simix/context.h"
-#include "gras_config.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");
+                                "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 CONTEXT_THREADS
-__thread smx_context_t smx_current_context;
+int smx_context_stack_size;
+int smx_context_stack_size_was_set = 0;
+#ifdef HAVE_THREAD_LOCAL_STORAGE
+static __thread smx_context_t smx_current_context_parallel;
 #else
-smx_context_t smx_current_context;
+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 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 || !strcmp(smx_context_factory_name, "ucontext")) {
+
+
+      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);
       }
-      else if (!strcmp(smx_context_factory_name, "thread")) {
-	/* use os threads (either pthreads or windows ones) */
-        SIMIX_ctx_thread_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);
+        /* use raw contexts */
+        SIMIX_ctx_raw_factory_init(&simix_global->context_factory);
       }
+#endif
       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 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)
 {
@@ -68,9 +94,37 @@ 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");
+  xbt_dict_remove((xbt_dict_t) _sg_cfg_set,"contexts/factory");
+}
+
+void *SIMIX_context_stack_new(void)
+{
+  return xbt_malloc0(smx_context_stack_size);
+}
+
+void SIMIX_context_stack_delete(void *stack)
+{
+  xbt_free(stack);
+}
+
+/**
+ * \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;
 }
 
 /**
@@ -78,32 +132,101 @@ void SIMIX_context_mod_exit(void)
  * 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
  */
 void SIMIX_context_set_nthreads(int nb_threads) {
-
-  xbt_assert1(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, "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)
+ * \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
  */
-int SIMIX_context_get_nthreads(void) {
-  return smx_parallel_contexts;
+XBT_INLINE int SIMIX_context_get_parallel_threshold(void) {
+  return smx_parallel_threshold;
 }
 
 /**
- * \brief Returns whether some parallel threads are used
- * for the user contexts.
- * \return 1 if parallelism is used
+ * \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
  */
-int SIMIX_context_is_parallel(void) {
-  return smx_parallel_contexts > 1;
+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;
+  }
+}