Graphics FIFO error, How did I cause it?

[Scott E. Townsend]

As the subject line states, I'm getting graphics FIFO errors logged in
/usr/adm/SYSLOG:

Jul 12 07:48:03 bach grcond[1113]: CIO: WARNING: Graphics error: GE PC = 11940
Jul 12 07:48:03 bach grcond[1113]: CIO: 
Jul 12 07:48:03 bach grcond[1113]: CIO: gr1_fifo_intr: TIMEOUT (FIFO still > hal
f full)!

The situation is a heavily loaded system running the usual 4Sight windows
(just wsh's) and a simple surface plotter displaying near real-time
computation data.  The computation is limited to the Iris's graphics speed,
since without the surface plotter running the computation runs a lot quicker.
(The computation is performed on an attached parallel processor, the only
computations on the Iris are for the graphics only)

The system is a Personal Iris, running IRIX 3.2.  The surface program is
using tmeshes on an RGB mode display, nothing amazing.

I get these not on every run, but so frequently that it's getting real
annoying. (The NeWS server goes down and I have to log in again)

Any ideas on what's happening?  Or even better, any ideas on what I can
change to avoid this?  Any suggestions would be appreciated.

(For instance, is there a way to know that I'm about to "overdrive" the
graphics system, and pause for a while?)

--
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Scott Townsend               |   Phone: 216-433-8101
NASA Lewis Research Center   |   Mail Stop: 5-11
Cleveland, Ohio  44135       |   Email: fsset at bach.lerc.nasa.gov
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