[Tfug] Troubleshooting an X/TCP/appliance/OS hazzard

[Bexley Hall]

Hi,

I run most of my machines headless (X terminals).
I recently replaced an Ultra5 with a SPARCstation5
(quieter, lower power consumption, etc.).  Both
boxes run NetBSD 3.1 (though the SS5 runs the 32-bit
system while the U5 runs the 64-bit) with virtually
identical (software) configurations (services, etc.).

I noticed that periodically (*regularly*!), my session
at the terminal would "freeze" momentarily.  I.e.,
click or type on something and nothing would happen
(though the mouse cursor would still move properly,
etc.).  Then, a few seconds later, the system would
"catch up" with me.

For example, move the mouse cursor to an xterm window,
type "ls -alR" \n and *wait*.  Then, "suddenly",
the selected window would be highlighted (receive
the focus), the "ls -alR" would appear followed
immediately by the recursive, long directory listing.

So, nothing is getting *lost*... just *delayed*.

Other clues:

The system is largely idle.  I've even gone so far
as to kill all unnecessary tasks and note no change
in this behaviour.  There doesn't appear to be any
activity *during* the "pause" (no thrashing, no
disk activity, nothing odd happening on the network,
etc.).

With the window manager running on the login host,
moving the mouse to a new window will not result in
a change in the "focus feedback" (i.e. titlebar
highlight changes) *during* the "pause -- though
as soon as the pause is over, the expected
highlighting occurs.  (I have yet to try running
a window manager *on* the X terminal to verify this
symptom disappears -- I expect it will).

Running an X session directly on the login host
(i.e. drag a monitor over to the machine) and
this behaviour is absent -- i.e. things work as
expected.

The U5 does not exhibit this behaviour.

As I am not fond of troubleshooting bugs in other
people's code unless I *must*, I am looking for other
clues to chase down *before* digging deeper.

Any suggestions of other "easy" (?) tests to help
isolate whether the problem is in the X terminal,
SS5, OS, etc.?

Thx,
--don


 
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