added option to bind threads to physical cores

[simgrid.git] / src / xbt / parmap.c

diff --git a/src/xbt/parmap.c b/src/xbt/parmap.c
index cdb6e91..b5d9025 100644 (file)
--- a/src/xbt/parmap.c
+++ b/src/xbt/parmap.c
@@ -128,12 +128,23 @@ xbt_parmap_t xbt_parmap_new(unsigned int num_workers, e_xbt_parmap_mode_t mode)
   /* Create the pool of worker threads */
   xbt_parmap_thread_data_t data;
   parmap->workers[0] = NULL;
+#ifdef CORE_BINDING  
+  unsigned int core_bind = 0;
+#endif  
   for (i = 1; i < num_workers; i++) {
     data = xbt_new0(s_xbt_parmap_thread_data_t, 1);
     data->parmap = parmap;
     data->worker_id = i;
     parmap->workers[i] = xbt_os_thread_create(NULL, xbt_parmap_worker_main,
                                               data, NULL);
+#ifdef CORE_BINDING  
+    xbt_os_thread_bind(parmap->workers[i], core_bind); 
+    if(core_bind!=xbt_os_get_numcores()){
+      core_bind++;
+    } else {
+      core_bind = 0; 
+    }
+#endif    
   }
   return parmap;
 }
@@ -272,14 +283,14 @@ static void xbt_parmap_set_mode(xbt_parmap_t parmap, e_xbt_parmap_mode_t mode)
  */
 void xbt_parmap_apply(xbt_parmap_t parmap, void_f_pvoid_t fun, xbt_dynar_t data)
 {
-  /* Assign resources to worker threads */
+  /* Assign resources to worker threads (we are maestro here)*/
   parmap->fun = fun;
   parmap->data = data;
   parmap->index = 0;
-  parmap->master_signal_f(parmap);
-  xbt_parmap_work(parmap);
-  parmap->master_wait_f(parmap);
-  XBT_DEBUG("Job done");
+  parmap->master_signal_f(parmap); // maestro runs futex_wait to wake all the minions (the working threads)
+  xbt_parmap_work(parmap);         // maestro works with its minions
+  parmap->master_wait_f(parmap);   // When there is no more work to do, then maestro waits for the last minion to stop
+  XBT_DEBUG("Job done");           //   ... and proceeds
 }
 
 /**