Create an MCA parameter (ess_base_stream_buffering) that allows the user to override the system default for buffering of stdout/stderr streams. See 'man setvbuf' for more information.

Note: I am working on a system that buffered all output until the application fishished due to a default of 'fully buffered.' This makes debugging painful. This switch fixed the problem by allowing me to adjust the buffering.

This commit was SVN r26119.

orte/mca/ess/base/base.h

@@ -10,6 +10,7 @@
  * Copyright (c) 2004-2005 The Regents of the University of California.
  *                         All rights reserved.
  * Copyright (c) 2011      Cisco Systems, Inc.  All rights reserved.
+ * Copyright (c) 2012      Oak Ridge National Labs.  All rights reserved.
  * $COPYRIGHT$
  * 
  * Additional copyrights may follow
@@ -56,6 +57,11 @@ ORTE_DECLSPEC int orte_ess_base_close(void);
  */
 ORTE_DECLSPEC extern int orte_ess_base_output;
 
+/*
+ * stdout/stderr buffering control parameter
+ */
+ORTE_DECLSPEC extern int orte_ess_base_std_buffering;
+
 ORTE_DECLSPEC extern opal_list_t orte_ess_base_components_available;
 
 #if ORTE_ENABLE_EPOCH

orte/mca/ess/base/ess_base_open.c

@@ -10,6 +10,7 @@
  * Copyright (c) 2004-2005 The Regents of the University of California.
  *                         All rights reserved.
  * Copyright (c) 2011 Cisco Systems, Inc.  All rights reserved.
+ * Copyright (c) 2012      Oak Ridge National Labs.  All rights reserved.
  * $COPYRIGHT$
  * 
  * Additional copyrights may follow
@@ -51,10 +52,19 @@ orte_ess_base_module_t orte_ess = {
     NULL   /* ft_event */
 };
 int orte_ess_base_output;
+int orte_ess_base_std_buffering = -1;
 
 int
 orte_ess_base_open(void)
 {
+    mca_base_param_reg_int_name("ess_base",
+                                "stream_buffering",
+                                "Adjust buffering for stdout/stderr "
+                                "[-1 system default] [0 unbuffered] [1 line buffered] [2 fully buffered] "
+                                "(Default: -1)",
+                                false, false,
+                                -1, &orte_ess_base_std_buffering);
+
     orte_ess_base_output = opal_output_open(NULL);
     
     OBJ_CONSTRUCT(&orte_ess_base_components_available, opal_list_t);

orte/mca/ess/base/ess_base_std_app.c

@@ -9,7 +9,7 @@
  *                         University of Stuttgart.  All rights reserved.
  * Copyright (c) 2004-2005 The Regents of the University of California.
  *                         All rights reserved.
- * Copyright (c) 2010-2011 Oak Ridge National Labs.  All rights reserved.
+ * Copyright (c) 2010-2012 Oak Ridge National Labs.  All rights reserved.
  * $COPYRIGHT$
  * 
  * Additional copyrights may follow
@@ -65,6 +65,26 @@ int orte_ess_base_app_setup(void)
     int ret;
     char *error = NULL;
 
+    /*
+     * stdout/stderr buffering
+     * If the user requested to override the default setting then do
+     * as they wish.
+     */
+    if( orte_ess_base_std_buffering > -1 ) {
+        if( 0 == orte_ess_base_std_buffering ) {
+            setvbuf(stdout, NULL, _IONBF, 0);
+            setvbuf(stderr, NULL, _IONBF, 0);
+        }
+        else if( 1 == orte_ess_base_std_buffering ) {
+            setvbuf(stdout, NULL, _IOLBF, 0);
+            setvbuf(stderr, NULL, _IOLBF, 0);
+        }
+        else if( 2 == orte_ess_base_std_buffering ) {
+            setvbuf(stdout, NULL, _IOFBF, 0);
+            setvbuf(stderr, NULL, _IOFBF, 0);
+        }
+    }
+
     /* open the errmgr */
     if (ORTE_SUCCESS != (ret = orte_errmgr_base_open())) {
         ORTE_ERROR_LOG(ret);