[racket] DrRacket spiking CPU

I've installed DrRacket in an Ubuntu lab at school (with, admittedly,
some fairly old systems), and while it is briefly responsive when I
first fire it up, it then spikes to 100% CPU and is totally useless for
a bit; if I take focus away it eventually registers the keystrokes I
made, but the moment I give focus back (without even clicking or typing
anything) it spikes again.  This is occurring under both 5.1.2 and
5.1.3.  If I run command-line racket it seems to be just fine.

Running an strace indicates that during the spike there are a LOT of
reads from file descriptors linked to unix sockets (6 and 10) that fail
with an EAGAIN error.  What's especially puzzling to me is that the
program runs at all if this is happening (and as I said, it does,
eventually, come through with a response to the few keystrokes I'd
queued up).

I'm still triaging, but has anyone seen anything like this?  Anyone have
ideas where I should look next?

-- 
-=-Don Blaheta-=-=-blahetadp at blahedo.org-=-=-=-<http://www.blahedo.org/>-=-
"There's safety in numbers.  Large prime numbers."	--John Gilmore