X-Git-Url: http://info.iut-bm.univ-fcomte.fr/pub/gitweb/simgrid.git/blobdiff_plain/8a24d575ab0a1d565521896081c6d5e0f1dfb941..056593992509f32c834360664489e8e239d22802:/src/simix/smx_context.c

diff --git a/src/simix/smx_context.c b/src/simix/smx_context.c
index 1044a01ec2..7e0b7e56c7 100644
--- a/src/simix/smx_context.c
+++ b/src/simix/smx_context.c
@@ -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
+__thread smx_context_t smx_current_context;
+#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 int smx_parallel_contexts = 1;
+static int smx_parallel_threshold = 2;
 
 /** 
  * This function is called by SIMIX_global_init() to initialize the context module.
@@ -29,10 +41,25 @@ void SIMIX_context_mod_init(void)
     if (smx_factory_initializer_to_use) {
       (*smx_factory_initializer_to_use)(&(simix_global->context_factory));
     }
-    else { /* use the factory specified by --cfg=simix/ctx:value */
-      if (smx_context_factory_name == NULL || !strcmp(smx_context_factory_name, "ucontext")) {
+    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 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
 }
 
 /**
@@ -61,5 +106,99 @@ void SIMIX_context_mod_exit(void)
     finalize_factory = simix_global->context_factory->finalize;
     (*finalize_factory) (&simix_global->context_factory);
   }
-  xbt_dict_remove((xbt_dict_t) _surf_cfg_set,"simix/context");
+  xbt_dict_remove((xbt_dict_t) _surf_cfg_set,"contexts/factory");
+}
+
+/**
+ * \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.
+ * 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, "No thread support for parallel context execution");
+#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
+ */
+XBT_INLINE int SIMIX_context_is_parallel(void) {
+  return smx_parallel_contexts > 1;
+}
+
+/**
+ * \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 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 Returns the current context of this thread.
+ * \return the current context of this thread
+ */
+XBT_INLINE smx_context_t SIMIX_context_get_current(void)
+{
+#ifdef HAVE_THREAD_LOCAL_STORAGE
+  return smx_current_context;
+#else
+  return xbt_os_thread_get_specific(smx_current_context_key);
+#endif
+}
+
+/**
+ * \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)
+{
+#ifdef HAVE_THREAD_LOCAL_STORAGE
+  smx_current_context = context;
+#else
+  xbt_os_thread_set_specific(smx_current_context_key, context);
+#endif
 }
+