X-Git-Url: http://info.iut-bm.univ-fcomte.fr/pub/gitweb/simgrid.git/blobdiff_plain/29202b3071fe6d3b7146dcd47218ab699ece7a62..ab6dbae7f0ae8ebd519f86898d23e909f5f57b56:/src/simix/smx_context.c

diff --git a/src/simix/smx_context.c b/src/simix/smx_context.c
index c2bf12d475..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
@@ -9,8 +9,10 @@
 #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");
@@ -18,8 +20,15 @@ XBT_LOG_NEW_DEFAULT_SUBCATEGORY(simix_context, simix,
 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;
-smx_context_t smx_current_context;
-static int smx_parallel_contexts;
+
+#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;
 
 /** 
  * This function is called by SIMIX_global_init() to initialize the context module.
@@ -29,12 +38,27 @@ 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 || !strcmp(smx_context_factory_name, "ucontext")) {
+
+    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 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) */
@@ -45,10 +69,28 @@ 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
 }
 
 /**
@@ -61,11 +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.
@@ -76,27 +136,123 @@ void SIMIX_context_mod_exit(void)
  *
  * \param nb_threads the number of threads to use
  */
-void SIMIX_context_set_parallel_threads(int nb_threads) {
+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_assert1(nb_threads > 0, "Invalid number of parallel threads: %d", nb_threads);
   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_parallel_threads() {
-  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() {
-  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) {
+  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\"");
+  }
+}
+
+/**
+ * \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;
+  }
 }