21.2.17 pauses

I've just started noticing this, and it's getting annoying. This is running on a Solaris 2.5.1 box, compiled with gcc 2.7.2.2, Sun openwin Every once in a while, xemacs just pauses for no apparent reason. It's not GC because the GC mouse pointer doesn't appear. There's no busy icon or anything. It starts using 100% CPU, for a few seconds, as shown by top and Perfmeter. This also happens on Linux box at home where the effect is more noticeable because the machine is much slower. Any one else seen this? It's getting annoying. I don't remember seeing this in 21.2.16. Ray