more informative error message when an invalid context factory is selected

[simgrid.git] / src / simix / smx_context.c

diff --git a/src/simix/smx_context.c b/src/simix/smx_context.c
index 9a526f5..7e0b7e5 100644 (file)
--- a/src/simix/smx_context.c
+++ b/src/simix/smx_context.c
@@ -9,7 +9,8 @@
 #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"
 
@@ -20,14 +21,15 @@ char* smx_context_factory_name = NULL; /* factory name specified by --cfg=contex
 smx_ctx_factory_initializer_t smx_factory_initializer_to_use = NULL;
 int smx_context_stack_size = 128 * 1024;
 
-#ifdef CONTEXT_THREADS
+#ifdef HAVE_THREAD_LOCAL_STORAGE
 __thread smx_context_t smx_current_context;
 #else
-smx_context_t smx_current_context;
+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 = 1;
+static int smx_parallel_threshold = 2;
 
 /** 
  * This function is called by SIMIX_global_init() to initialize the context module.
@@ -40,9 +42,24 @@ void SIMIX_context_mod_init(void)
       (*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) */
@@ -53,10 +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
 }
 
 /**
@@ -141,3 +176,29 @@ 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
+}
+