Using kevent to catch laptop disk I/O culprit?

[George Hartzell]

I'm working on keeping my laptop disk spun down and am using the
process of elimination to figure out who's always spinning up the
disk.

So far, I've put /tmp on an mfs, and I just installed Robert Sexton's
hw.ata.suspend patch from the freebsd-mobile archives.

I'm slowly killing off and/or fine tuning various daemons to see if
they're responsible for all of the IO, and it occured to me that
the kevent/kqueue stuff might be a great way to actually see who's
writing what, when.

Has anyone written the necessary parts to get this kind of a simple
filesystem trace?

g.