X-Git-Url: http://info.iut-bm.univ-fcomte.fr/pub/gitweb/simgrid.git/blobdiff_plain/70439fdf4efc3ac256a832dcad7b3ce04c35be23..a23e91ed7615232922aa1b38cef206dce24eb072:/src/simix/smx_context_boost.cpp

diff --git a/src/simix/smx_context_boost.cpp b/src/simix/smx_context_boost.cpp
new file mode 100644
index 0000000000..ce8d08a2e0
--- /dev/null
+++ b/src/simix/smx_context_boost.cpp
@@ -0,0 +1,168 @@
+/* Copyright (c) 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. */
+
+/** @file Userspace context switching implementation based on Boost.Context */
+
+#include <cstdint>
+
+#include <boost/context/all.hpp>
+
+#include "xbt/log.h"
+#include "smx_private.h"
+#include "internal_config.h"
+
+XBT_LOG_EXTERNAL_DEFAULT_CATEGORY(simix_context);
+
+typedef struct s_smx_ctx_boost {
+  s_smx_ctx_base_t super;       /* Fields of super implementation */
+  boost::context::fcontext_t* fc;
+  void* stack;
+} s_smx_ctx_boost_t, *smx_ctx_boost_t;
+
+static int smx_ctx_boost_factory_finalize(smx_context_factory_t *factory);
+static smx_context_t
+smx_ctx_boost_create_context(xbt_main_func_t code, int argc, char **argv,
+    void_pfn_smxprocess_t cleanup_func, smx_process_t process);
+static void smx_ctx_boost_free(smx_context_t context);
+
+static void smx_ctx_boost_wrapper(std::intptr_t arg);
+
+static void smx_ctx_boost_stop_serial(smx_context_t context);
+static void smx_ctx_boost_suspend_serial(smx_context_t context);
+static void smx_ctx_boost_resume_serial(smx_process_t first_process);
+static void smx_ctx_boost_runall_serial(void);
+
+static unsigned long boost_process_index = 0;
+static boost::context::fcontext_t boost_maestro_fcontext;
+static smx_ctx_boost_t boost_maestro_context;
+
+void SIMIX_ctx_boost_factory_init(smx_context_factory_t *factory)
+{
+  smx_ctx_base_factory_init(factory);
+  XBT_VERB("Activating boost context factory");
+
+  (*factory)->finalize = smx_ctx_boost_factory_finalize;
+  (*factory)->create_context = smx_ctx_boost_create_context;
+  /* Do not overload that method (*factory)->finalize */
+  (*factory)->free = smx_ctx_boost_free;
+  (*factory)->name = "smx_boost_context_factory";
+
+  if (SIMIX_context_is_parallel()) {
+    THROWF(arg_error, 0, "No thread support for parallel context execution");
+  } else {
+    (*factory)->stop = smx_ctx_boost_stop_serial;
+    (*factory)->suspend = smx_ctx_boost_suspend_serial;
+    (*factory)->runall = smx_ctx_boost_runall_serial;
+  }
+}
+
+/* Initialization functions */
+
+static int smx_ctx_boost_factory_finalize(smx_context_factory_t *factory)
+{
+  return smx_ctx_base_factory_finalize(factory);
+}
+
+static smx_context_t
+smx_ctx_boost_create_context(xbt_main_func_t code, int argc, char **argv,
+    void_pfn_smxprocess_t cleanup_func, smx_process_t process)
+{
+  smx_ctx_boost_t context =
+      (smx_ctx_boost_t) smx_ctx_base_factory_create_context_sized(
+          sizeof(s_smx_ctx_boost_t),
+          code,
+          argc,
+          argv,
+          cleanup_func,
+          process);
+
+  /* if the user provided a function for the process then use it,
+     otherwise it is the context for maestro */
+  if (code) {
+    context->stack = SIMIX_context_stack_new();
+    // We need to pass the bottom of the stack to make_fcontext,
+    // depending on the stack direction it may be the lower or higher address:
+#if PTH_STACKGROWTH == -1
+    void* stack = (char*) context->stack + smx_context_usable_stack_size - 1;
+#else
+    void* stack = context->stack;
+#endif
+   context->fc = boost::context::make_fcontext(
+                      stack,
+                      smx_context_usable_stack_size,
+                      smx_ctx_boost_wrapper);
+  } else if (process != nullptr && boost_maestro_context == nullptr) {
+    context->stack = nullptr;
+    context->fc = &boost_maestro_fcontext;
+    boost_maestro_context = context;
+  }
+
+  return (smx_context_t) context;
+}
+
+static void smx_ctx_boost_free(smx_context_t c)
+{
+  smx_ctx_boost_t context = (smx_ctx_boost_t) c;
+  if (!context)
+    return;
+  if ((smx_ctx_boost_t) c == boost_maestro_context)
+    boost_maestro_context = nullptr;
+  SIMIX_context_stack_delete(context->stack);
+  smx_ctx_base_free(c);
+}
+
+static void smx_ctx_boost_wrapper(std::intptr_t arg)
+{
+  smx_context_t context = (smx_context_t) arg;
+  context->code(context->argc, context->argv);
+  smx_ctx_boost_stop_serial(context);
+}
+
+static void smx_ctx_boost_stop_serial(smx_context_t context)
+{
+  smx_ctx_base_stop(context);
+  simix_global->context_factory->suspend(context);
+}
+
+static void smx_ctx_boost_suspend_serial(smx_context_t context)
+{
+  /* determine the next context */
+  smx_ctx_boost_t next_context;
+  unsigned long int i = boost_process_index++;
+
+  if (i < xbt_dynar_length(simix_global->process_to_run)) {
+    /* execute the next process */
+    XBT_DEBUG("Run next process");
+    next_context = (smx_ctx_boost_t) xbt_dynar_get_as(
+        simix_global->process_to_run, i, smx_process_t)->context;
+  }
+  else {
+    /* all processes were run, return to maestro */
+    XBT_DEBUG("No more process to run");
+    next_context = (smx_ctx_boost_t) boost_maestro_context;
+  }
+  SIMIX_context_set_current((smx_context_t) next_context);
+  boost::context::jump_fcontext(
+    ((smx_ctx_boost_t)context)->fc, next_context->fc, (intptr_t)next_context);
+}
+
+static void smx_ctx_boost_resume_serial(smx_process_t first_process)
+{
+  smx_ctx_boost_t context = (smx_ctx_boost_t) first_process->context;
+  SIMIX_context_set_current((smx_context_t) context);
+  boost::context::jump_fcontext(boost_maestro_context->fc, context->fc,
+    (intptr_t)context);
+}
+
+static void smx_ctx_boost_runall_serial(void)
+{
+  smx_process_t first_process =
+      xbt_dynar_get_as(simix_global->process_to_run, 0, smx_process_t);
+  boost_process_index = 1;
+
+  /* execute the first process */
+  smx_ctx_boost_resume_serial(first_process);
+}