On Sat, 14 Jul 2007, Alan Barrett wrote:
> I still encounter hands in which firefox is unresponsive, and most of
> its lwps are in "parked" state.

It appears that the problem is related to the process being swapped out.
Every time firefox is hung (unresponsive to mouse clicks, doesn't even
redraw the window when it is brought to the foreground), I have found
that "ps -l" reports that the process is swapped out ("W" in the second
character of the "STAT" column), and that "ps -s" reports that every lwp
is swapped out.  Most lwps have WCHAN = "parked", but there's always one
with "-", and one with something else (usually "select" or "poll").

--apb (Alan Barrett)