X-Git-Url: http://info.iut-bm.univ-fcomte.fr/pub/gitweb/simgrid.git/blobdiff_plain/7eef625065d0b3af4a64b5665009491426db974f..7ad85b03568dabade546f7948aaf7279059e9269:/src/simix/smx_context.c

diff --git a/src/simix/smx_context.c b/src/simix/smx_context.c
index 09c75b03bd..a801c0451b 100644
--- a/src/simix/smx_context.c
+++ b/src/simix/smx_context.c
@@ -1,148 +1,338 @@
 /* a fast and simple context switching library                              */
 
-/* Copyright (c) 2009, 2010. The SimGrid Team.
+/* Copyright (c) 2009-2015. The SimGrid Team.
  * All rights reserved.                                                     */
 
 /* This program is free software; you can redistribute it and/or modify it
  * under the terms of the license (GNU LGPL) which comes with this package. */
 
-#include "portable.h"
+#include "src/portable.h"
 #include "xbt/log.h"
 #include "xbt/swag.h"
-#include "private.h"
+#include "xbt/xbt_os_thread.h"
+#include "smx_private.h"
+#include "simgrid/sg_config.h"
+#include "src/internal_config.h"
+#include "simgrid/modelchecker.h"
 
-#ifdef HAVE_LUA
-#include <lauxlib.h>
+
+#ifdef _WIN32
+#include <windows.h>
+#include <malloc.h>
+#else
+#include <sys/mman.h>
 #endif
 
-#ifdef HAVE_RUBY
- void SIMIX_ctx_ruby_factory_init(smx_context_factory_t *factory);
-#endif 
- 
-XBT_LOG_NEW_DEFAULT_SUBCATEGORY(simix_context, simix, "Context switching mecanism");
+#ifdef __MINGW32__ 
+#define _aligned_malloc __mingw_aligned_malloc 
+#define _aligned_free  __mingw_aligned_free 
+#endif //MINGW
+
+#ifdef HAVE_VALGRIND_VALGRIND_H
+# include <valgrind/valgrind.h>
+#endif
 
-const char *xbt_ctx_factory_to_use = NULL;
+XBT_LOG_NEW_DEFAULT_SUBCATEGORY(simix_context, simix,
+                                "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;
+int smx_context_stack_size_was_set = 0;
+int smx_context_guard_size;
+int smx_context_guard_size_was_set = 0;
+#ifdef HAVE_THREAD_LOCAL_STORAGE
+static XBT_THREAD_LOCAL 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;
+static e_xbt_parmap_mode_t smx_parallel_synchronization_mode = XBT_PARMAP_DEFAULT;
 
 /** 
- * This function is call by SIMIX_global_init() to initialize the context module.
+ * 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 context factory to use to create the context(depends of the macro definitions) */
-    if (xbt_ctx_factory_to_use) {
-      SIMIX_context_select_factory(xbt_ctx_factory_to_use);
-    } else {
-#ifdef CONTEXT_THREADS
-    /* context switch based os thread */
-    SIMIX_ctx_thread_factory_init(&simix_global->context_factory);
-#elif !defined(_XBT_WIN32)
-    /* context switch based ucontext */
-    SIMIX_ctx_sysv_factory_init(&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);
+    }
+    else { /* use the factory specified by --cfg=contexts/factory:value */
+
+
+      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);
+      }
+#endif
+#ifdef HAVE_RAWCTX
+      else if (!strcmp(smx_context_factory_name, "raw")) {
+        /* use raw contexts */
+        SIMIX_ctx_raw_factory_init(&simix_global->context_factory);
+      }
+#endif
+#ifdef HAVE_BOOST_CONTEXT
+      else if (!strcmp(smx_context_factory_name, "boost")) {
+        /* use Boost.Context */
+        SIMIX_ctx_boost_factory_init(&simix_global->context_factory);
+      }
+#endif
+      else {
+        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
-    /* context switch is not allowed on Windows */
-#error ERROR [__FILE__, line __LINE__]: no context based implementation specified.
+        XBT_ERROR("  (raw contexts were 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 was disabled at compilation time on this machine -- check configure logs for details)");
+#endif
+#ifdef HAVE_BOOST_CONTEXT
+        XBT_ERROR("  boost: this uses the boost libraries context implementation");
+#else
+        XBT_ERROR("  (boost was disabled at compilation time on this machine -- check configure logs for details. Did you install the libboost-context-dev package?)");
+#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)
 {
   if (simix_global->context_factory) {
     smx_pfn_context_factory_finalize_t finalize_factory;
-    
+
     /* 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) _sg_cfg_set,"contexts/factory");
 }
 
-/**
- * This function is used to change the context factory.
- * Warning: it destroy all the existing processes (even for maestro), and it
- * will create a new maestro process using the new context factory.
- */
-int SIMIX_context_select_factory(const char *name)
+void *SIMIX_context_stack_new(void)
 {
-  /* if a context factory is already instantiated and it is different from the
-     newly selected one, then kill all the processes, exit the context module
-     and initialize the new factory.
-  */
-  
+  void *stack;
 
-  if (simix_global->context_factory != NULL) {
-    if (strcmp(simix_global->context_factory->name, name)){
+  /* FIXME: current code for stack overflow protection assumes that stacks are
+   * growing downward (PTH_STACKGROWTH == -1).  Protected pages need to be put
+   * after the stack when PTH_STACKGROWTH == 1. */
 
-      SIMIX_process_killall();
-      
-      /* kill maestro process */
-      SIMIX_context_free(simix_global->maestro_process->context);
-      free(simix_global->maestro_process);  
-      simix_global->maestro_process = NULL;
+  if (smx_context_guard_size > 0 && !MC_is_active()) {
 
-      SIMIX_context_mod_exit();
+#if defined(_XBT_WIN32) || (PTH_STACKGROWTH != -1)
+    static int warned_once = 0;
+    if (!warned_once) {
+      XBT_WARN("Stack overflow protection is known to be broken on your system.  Either you're on Windows or PTH_STACKGROWTH != -1 (current value is %d).",
+               PTH_STACKGROWTH);
+      warned_once = 1;
     }
-    else
-      /* the same context factory is requested return directly */
-      return 0;
+#endif
+
+    size_t size = smx_context_stack_size + smx_context_guard_size;
+#ifdef HAVE_MC
+    /* Cannot use posix_memalign when HAVE_MC. Align stack by hand, and save the
+     * pointer returned by xbt_malloc0. */
+    char *alloc = xbt_malloc0(size + xbt_pagesize);
+    stack = alloc - ((uintptr_t)alloc & (xbt_pagesize - 1)) + xbt_pagesize;
+    *((void **)stack - 1) = alloc;
+#elif !defined(_XBT_WIN32)
+    if (posix_memalign(&stack, xbt_pagesize, size) != 0)
+      xbt_die("Failed to allocate stack.");
+#else
+    stack = _aligned_malloc(size, xbt_pagesize);
+#endif
+
+#ifndef _XBT_WIN32
+    if (mprotect(stack, smx_context_guard_size, PROT_NONE) == -1) {
+      xbt_die("Failed to protect stack: %s", strerror(errno));
+      /* This is fatal. We are going to fail at some point when
+         we tryi reusing this. */
+    }
+#endif
+    stack = (char *)stack + smx_context_guard_size;
+  } else {
+    stack = xbt_malloc0(smx_context_stack_size);
   }
-  
-  /* init the desired factory */
-  SIMIX_context_init_factory_by_name(&simix_global->context_factory, name);
 
-  SIMIX_create_maestro_process ();
+#ifdef HAVE_VALGRIND_VALGRIND_H
+  unsigned int valgrind_stack_id =
+    VALGRIND_STACK_REGISTER(stack, (char *)stack + smx_context_stack_size);
+  memcpy((char *)stack + smx_context_usable_stack_size, &valgrind_stack_id,
+         sizeof valgrind_stack_id);
+#endif
+
+  return stack;
+}
 
+void SIMIX_context_stack_delete(void *stack)
+{
+  if (!stack)
+    return;
+
+#ifdef HAVE_VALGRIND_VALGRIND_H
+  unsigned int valgrind_stack_id;
+  memcpy(&valgrind_stack_id, (char *)stack + smx_context_usable_stack_size,
+         sizeof valgrind_stack_id);
+  VALGRIND_STACK_DEREGISTER(valgrind_stack_id);
+#endif
+
+#ifndef WIN32
+  if (smx_context_guard_size > 0 && !MC_is_active()) {
+    stack = (char *)stack - smx_context_guard_size;
+    if (mprotect(stack, smx_context_guard_size,
+                 PROT_READ | PROT_WRITE) == -1) {
+      XBT_WARN("Failed to remove page protection: %s", strerror(errno));
+      /* try to pursue anyway */
+    }
+#ifdef HAVE_MC
+    /* Retrieve the saved pointer.  See SIMIX_context_stack_new above. */
+    stack = *((void **)stack - 1);
+#endif
+  }
+#endif
 
+  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;
+}
+
+/**
+ * \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 (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) {
+  if (nb_threads<=0) {  
+     nb_threads = xbt_os_get_numcores();
+     XBT_INFO("Auto-setting contexts/nthreads to %d",nb_threads);
+  }   
   
-  return 0;
+  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 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 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;
 }
 
 /**
- * Initializes a context factory given by its name
+ * \brief Returns the synchronization mode used when processes are run in
+ * parallel.
+ * \return how threads are synchronized if processes are run in parallel
  */
-void SIMIX_context_init_factory_by_name(smx_context_factory_t * factory,
-                                        const char *name)
+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 (!strcmp(name, "java"))
-#ifdef HAVE_JAVA     
-    SIMIX_ctx_java_factory_init(factory);
-#else
-    THROW0(not_found_error, 0, "Factory 'Java' does not exist: Java support was not compiled in the SimGrid library");
-#endif /* HAVE_JAVA */
-   
-  else if (!strcmp(name, "thread"))
-#ifdef CONTEXT_THREADS
-    SIMIX_ctx_thread_factory_init(factory);
-#else
-    THROW0(not_found_error, 0, "Factory 'thread' does not exist: thread support was not compiled in the SimGrid library");
-#endif /* CONTEXT_THREADS */
-   
-    else if (!strcmp(name, "sysv"))
-  #if !defined(_XBT_WIN32) && !defined(CONTEXT_THREADS)
-      SIMIX_ctx_sysv_factory_init(factory);
-  #else
-      THROW0(not_found_error, 0, "Factory 'sysv' does not exist: no System V thread support under Windows");
-  #endif
-    else if (!strcmp(name, "lua"))
-#ifdef HAVE_LUA
-      SIMIX_ctx_lua_factory_init(factory);
+  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;
+  }
+}
 
-    THROW0(not_found_error, 0, "Factory 'lua' does not exist: Lua support was not compiled in the SimGrid library");
-#endif /* HAVE_LUA */
-
-    else if (!strcmp(name,"ruby"))
-#ifdef HAVE_RUBY
-    SIMIX_ctx_ruby_factory_init(factory);
+/**
+ * \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
-     THROW0(not_found_error, 0, "Factory 'ruby' does not exist: Ruby support was not compiled in the SimGrid library");
+    xbt_os_thread_set_specific(smx_current_context_key, context);
 #endif
-  else
-    THROW1(not_found_error, 0, "Factory '%s' does not exist", name);
+  }
+  else {
+    smx_current_context_serial = context;
+  }
 }