Add a flag --cfg=contexts/parallel_threshold:n

At each scheduling rounding, the user contexts are run in
parallel if their number is greater than this threshold.

git-svn-id: svn+ssh://scm.gforge.inria.fr/svn/simgrid/simgrid/trunk@9560 48e7efb5-ca39-0410-a469-dd3cf9ba447f

diff --git a/include/simix/context.h b/include/simix/context.h
index 9d8ea2e..a82e607 100644 (file)
--- a/include/simix/context.h
+++ b/include/simix/context.h
@@ -100,9 +100,11 @@ void *smx_ctx_base_get_data(smx_context_t context);
 int smx_ctx_base_get_thread_id(void);
 
 /* parallelism */
-void SIMIX_context_set_nthreads(int nb_threads);
-int SIMIX_context_get_nthreads(void);
-int SIMIX_context_is_parallel(void);
+XBT_INLINE void SIMIX_context_set_nthreads(int nb_threads);
+XBT_INLINE int SIMIX_context_get_nthreads(void);
+XBT_INLINE int SIMIX_context_is_parallel(void);
+XBT_INLINE void SIMIX_context_set_parallel_threshold(int threshold);
+XBT_INLINE int SIMIX_context_get_parallel_threshold(void);
 
 SG_END_DECL()
 

diff --git a/src/simix/smx_context.c b/src/simix/smx_context.c
index 2da152b..fd93d16 100644 (file)
--- a/src/simix/smx_context.c
+++ b/src/simix/smx_context.c
@@ -27,6 +27,7 @@ smx_context_t smx_current_context;
 #endif
 
 static int smx_parallel_contexts = 1;
+static int smx_parallel_threshold = 20;
 
 /** 
  * This function is called by SIMIX_global_init() to initialize the context module.
@@ -83,7 +84,7 @@ void SIMIX_context_mod_exit(void)
  *
  * \param nb_threads the number of threads to use
  */
-void SIMIX_context_set_nthreads(int nb_threads) {
+XBT_INLINE void SIMIX_context_set_nthreads(int nb_threads) {
 
   xbt_assert1(nb_threads > 0, "Invalid number of parallel threads: %d", nb_threads);
   smx_parallel_contexts = nb_threads;
@@ -94,7 +95,7 @@ void SIMIX_context_set_nthreads(int nb_threads) {
  * for the user contexts.
  * \return the number of threads (1 means no parallelism)
  */
-int SIMIX_context_get_nthreads(void) {
+XBT_INLINE int SIMIX_context_get_nthreads(void) {
   return smx_parallel_contexts;
 }
 
@@ -103,7 +104,33 @@ int SIMIX_context_get_nthreads(void) {
  * for the user contexts.
  * \return 1 if parallelism is used
  */
-int SIMIX_context_is_parallel(void) {
+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;
+}
+

diff --git a/src/simix/smx_context_raw.c b/src/simix/smx_context_raw.c
index 9b2ac2b..f4a22c8 100644 (file)
--- a/src/simix/smx_context_raw.c
+++ b/src/simix/smx_context_raw.c
@@ -280,12 +280,12 @@ static int smx_ctx_raw_get_thread_id(){
 
 static void smx_ctx_raw_runall(xbt_dynar_t processes)
 {
-  if(xbt_dynar_length(processes) > 10){
+  if (xbt_dynar_length(processes) > SIMIX_context_get_parallel_threshold()) {
     DEBUG1("Runall // %lu", xbt_dynar_length(processes));
     raw_factory->self = smx_ctx_raw_self_parallel;
     raw_factory->get_thread_id = smx_ctx_raw_get_thread_id;
     smx_ctx_raw_runall_parallel(processes);
-  }else{
+  } else {
     DEBUG1("Runall serial %lu", xbt_dynar_length(processes));
     raw_factory->self = smx_ctx_base_self;
     raw_factory->get_thread_id = smx_ctx_base_get_thread_id;

diff --git a/src/surf/surf_config.c b/src/surf/surf_config.c
index 5227d67..e98f304 100644 (file)
--- a/src/surf/surf_config.c
+++ b/src/surf/surf_config.c
@@ -204,6 +204,11 @@ static void _surf_cfg_cb_contexts_nthreads(const char *name, int pos)
   SIMIX_context_set_nthreads(xbt_cfg_get_int(_surf_cfg_set, name));
 }
 
+static void _surf_cfg_cb_contexts_parallel_threshold(const char *name, int pos)
+{
+  SIMIX_context_set_parallel_threshold(xbt_cfg_get_int(_surf_cfg_set, name));
+}
+
 static void _surf_cfg_cb__surf_network_fullduplex(const char *name,
                                                   int pos)
 {
@@ -365,6 +370,13 @@ void surf_config_init(int *argc, char **argv)
                      xbt_cfgelm_int, &default_value_int, 1, 1,
                      _surf_cfg_cb_contexts_nthreads, NULL);
 
+    /* minimal number of user contexts to be run in parallel */
+    default_value_int = 20;
+    xbt_cfg_register(&_surf_cfg_set, "contexts/parallel_threshold",
+        "Minimal number of user contexts to be run in parallel",
+        xbt_cfgelm_int, &default_value_int, 1, 1,
+        _surf_cfg_cb_contexts_parallel_threshold, NULL);
+
     default_value_int = 0;
     xbt_cfg_register(&_surf_cfg_set, "fullduplex",
                      "Activate the interferences between uploads and downloads for fluid max-min models (LV08, CM03)",