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Re: [nv-l] Problem with dying event windows

To: nv-l@lists.us.ibm.com
Subject: Re: [nv-l] Problem with dying event windows
From: James Shanks <jshanks@us.ibm.com>
Date: Thu, 14 Oct 2004 14:16:26 -0400
Delivery-date: Thu, 14 Oct 2004 19:28:40 +0100
Envelope-to: nv-l-archive@lists.skills-1st.co.uk
In-reply-to: <OF3E5A7C37.0D8BA68D-ONC1256F2B.0041C00A-C1256F2B.00429D83@pl.ibm.com>
Reply-to: nv-l@lists.us.ibm.com
Sender: owner-nv-l@lists.us.ibm.com

Tracking nvevents is not simple in any case, and more so in your case.

  As an X-GUI app, it was not designed to keep a log.  When error messages were intended for the user, they are put in a pop-up window.  Unexpected  error messages, if any, are sent to stderr, and would  go to the command window that was active when the process was started.  Usually, these are grabbed and kept in the netview_<userid>.log, if that's how you started the NetView GUI.   If nvevents cores, the core also goes to the active directory of the active window.   But  nvevents will disappear without saying anything on receipt of just about  any signal other than SIGCHILD, so that it goes away whenever the  ovw process or the Control Desk does .  It's wasn't designed to stay up and keep running when a problem is encountered.

If your event windows were failing on the server X-GUI, then we'd be reasonably sure that we'd see any error message, if any were produced.
  But all bets are off when you telnet in through an X-emulator, which is one reason why we do not officially support them.  Another thing we have discovered over the years is that X emulators are quite sensitive to the level of the X11 library code used on the server, though they seldom tell you about that.  

So you might try to find out whether your emulator is expecting you to be using X11/R5 libraries or X11/R6.  Some of the newer ones don't work well with the R5 libraries on AIX.  But even if you cannot find out , take a  look into the /usr/OV/bin/netview script, if that how you are starting the daemons, and locate the "export LIBPATH" statement near the end.  Before 7.1.4 FixPack2  we concatenated the X11/R5 libraries ahead of the R6 ones, but discovered that caused problems with some control desk apps on later levels of AIX, so now it has been removed.  So if you see "/usr/lpp/X11/lib/R5" in the concatenation, remove it and just leave everything else.  

You also might have better luck running nvevents outside the control desk.  You can change that in /usr/OV/app-defaults/Nvevents, if you like.  Or you might try reducing the number of event windows you have open at once and see if the problem is load-related.

You see,  I disagree with the diagnosis that because there's nothing in your emulator logs, then the problem must be on the server.  I once had an AIX developer tell me that no application he knew of drove the X server on AIX harder than NetView does, especially with multiple event windows, because every event is a full-blown X widget, not just a color change like status is on the map.  So a rapid event flow is like what happens to the map when you start from nothing but a really good seed-file.  It populates and re-draws so rapidly that your eye can hardly follow it.  Ten events per second as a sustained load can make an event window on the server flicker so fast that you literally cannot read it all.  Much higher than that, and it will just "white out" as the X-server cannot draw the updates fast enough.  Now if that is a huge load for the X-server, imagine what kind of a load that is for the X-emulator.  Bottom line here, is you have any tuning parameters you can adjust on your emulator, try doubling them.

Maybe the user's of other X emulators can tell you about  adjustments they have made to theirs.  They may not have the same emulator, but they may well have made an adjustment to solve a similar problem.


James Shanks
Level 3 Support  for Tivoli NetView for UNIX and Windows
Tivoli Software / IBM Software Group

Bartlomiej Grenda <Bartlomiej.Grenda@pl.ibm.com>
Sent by: owner-nv-l@lists.us.ibm.com

10/12/2004 08:07 AM
Please respond to

Re: [nv-l] Problem with dying event windows

> This sounds like something X-related. I would be looking at the
> logs on the machines themselves for information from Reflection-X.
> Or see if there is any way to trace or debug Reflection-X. Have you
> recently installed any updates to R-X or the NetView server? Do you
> have the latest patches for R-X?

I've checked R-X logs. Unfortunately, there is nothing interesting there.
It seems that that this is on the server side...
As far as I understand - all Event Viewer windows for single user are
served by single nvevents process, so - if its die then all Event Viewer
windows will dissappear. How can I track nvevent process (log. debug,


Bartlomiej Grenda

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