Warn when the lots of stacks malloc()-ated by simgrid for transfer processes will take a long time to get initialized

src/core/workers.c

@@ -1047,6 +1047,10 @@ int starpu_initialize(struct starpu_conf *user_conf, int *argc, char ***argv)
 #endif
 #ifdef STARPU_SIMGRID
 	_starpu_simgrid_init();
+	/* Warn when the lots of stacks malloc()-ated by simgrid for transfer
+	 * processes will take a long time to get initialized */
+	if (getenv("MALLOC_PERTURB_"))
+		_STARPU_DISP("Warning: MALLOC_PERTURB_ is set, this makes simgrid runs very slow\n");
 #else
 #ifdef __GNUC__
 #ifndef __OPTIMIZE__