snow leopard – How do I debug an out-of-control “kernel_task” process?

Just recently I noticed my battery life having a pretty significant drop and the “kernel_task” process using quite a bit of CPU (a constant 1-6% on my 2.8ghz dual-core i7, 2010 MBP). Obviously I think the kernel_task’s CPU usage is contributing to the battery drop and I need to find out why.

Searching Google, it seems kernel_task is OS X’s version of Windows’s “svchost.exe” – the notorious do-everything process that you can’t ever truly debug, you have to just manually flip switches until one of them works.

Is there any way I can more easily get to the bottom of the out-of-control kernel_task activity? I haven’t tried a reboot because if that does “fix” it, it doesn’t really fix the underlying problem.

Activity Monitor shows the CPU usage. When I hit Inspect, it shows 77 threads, 2 ports, hours and hours of CPU time, Context Switches going up about 400 per second, and Mach Messages In and Out both going up at about 6,000 per second.

How can I somehow inspect or monitor this kernel_task process and figure out what’s actually using all this power?

(note: my current suspects are the recent 10.6.7 update, Firefox update from 4 beta 10 to RC, or ScreenResX – these are all things I’ve done recently that I can think of)