[Pvfs2-cvs] commit by pw in pvfs2: configure configure.in

[CVS commit program]

Update of /projects/cvsroot/pvfs2
In directory parlweb1:/tmp/cvs-serv14649

Modified Files:
	configure configure.in 
Log Message:
Warn people about the current polling situation in multi-BMI-device setups.
Users keep discovering this, and until we implement a separate thread per
device in BMI, PVFS will always perform poorly on both devices.


Index: configure
===================================================================
RCS file: /projects/cvsroot/pvfs2/configure,v
diff -u -p -p -u -r1.355 -r1.356
--- configure	22 Aug 2007 20:32:26 -0000	1.355
+++ configure	29 Aug 2007 17:13:53 -0000	1.356
@@ -16154,7 +16154,7 @@ if test "$ac_res" != no; then
   ac_cv_func_getmntent=yes
 
 cat >>confdefs.h <<\_ACEOF
-#define HAVE_GETMNTENT 1
+#define HAVE_GETMNTENT
 _ACEOF
 
 else
@@ -18332,6 +18332,22 @@ if test "x$WARN_ABOUT_HOSTNAMES" = "xyes
 echo "${ECHO_T}WARNING: gethostbyname is not supported on this machine: ALL ADDRESSES MUST BE IN DOT NOTATION." >&6; }
 fi
 
+
+if test x$BUILD_GM = x1 -o x$BUILD_MX = x1 -o x$BUILD_IB = x1 -o \
+	x$BUILD_OPENIB = x1 -o x$BUILD_PORTALS = x1 ; then
+    if test x$BUILD_BMI_TCP = x1 ; then
+	{ echo "$as_me:$LINENO: WARNING: You have selected to build PVFS to use a \"fast\" network
+		    interface, but have not disabled TCP.  The way this is
+		    currently implemented will lead to rather slow response
+		    times on the fast interface.  Suggest you configure with
+		    \"--without-bmi-tcp\" for the best performance." >&5
+echo "$as_me: WARNING: You have selected to build PVFS to use a \"fast\" network
+		    interface, but have not disabled TCP.  The way this is
+		    currently implemented will lead to rather slow response
+		    times on the fast interface.  Suggest you configure with
+		    \"--without-bmi-tcp\" for the best performance." >&2;}
+    fi
+fi
 
 { echo "$as_me:$LINENO: result: " >&5
 echo "${ECHO_T}" >&6; }

Index: configure.in
===================================================================
RCS file: /projects/cvsroot/pvfs2/configure.in,v
diff -u -p -p -u -r1.330 -r1.331
--- configure.in	22 Aug 2007 20:32:28 -0000	1.330
+++ configure.in	29 Aug 2007 17:13:54 -0000	1.331
@@ -1132,6 +1132,25 @@ if test "x$WARN_ABOUT_HOSTNAMES" = "xyes
 fi
 
 
+dnl
+dnl Warn about potential slowness if using a "fast" network along with
+dnl TCP.  Polling with timeout in BMI is implemented by sequentially asking
+dnl each device to poll for half of the timeout.  This leads to a fixed 5 ms
+dnl delay in the TCP device before the IB device can be queried, for instance.
+dnl When traffic will only appear on one device, suggest that TCP be disabled.
+dnl But leave TCP as default on, certainly, as that is what most people want.
+dnl
+if test x$BUILD_GM = x1 -o x$BUILD_MX = x1 -o x$BUILD_IB = x1 -o \
+	x$BUILD_OPENIB = x1 -o x$BUILD_PORTALS = x1 ; then
+    if test x$BUILD_BMI_TCP = x1 ; then
+	AC_MSG_WARN([You have selected to build PVFS to use a "fast" network
+		    interface, but have not disabled TCP.  The way this is
+		    currently implemented will lead to rather slow response
+		    times on the fast interface.  Suggest you configure with
+		    "--without-bmi-tcp" for the best performance.])
+    fi
+fi
+
 AC_MSG_RESULT()
 AC_MSG_RESULT([PVFS2 version string: $PVFS2_VERSION])