Nathan recently made a couple of changes to pthread, particularly
to do with recycling upcall stacks ASAP, and interrupted calls.

I'm not sure which of these or related changes makes the difference,
but with a fresh kernel and userland, xmms has been playing
continuously for over 5 hours.  The same test last week would have
hung xmms within 10 mins (often less).

Also interesting to note is that ps -s now shows xmms using 4 lwp's;
previously it would have had 6. 

I worry I'm speaking too soon, but even this much is a vast
improvement.  I haven't been having many problems with other
thread-using apps, but for those who have, I think it would be well
worthwhile testing -current sources and reporting results.

Thanks Nathan!

--
Dan.