This blog forms part of the http://performanceGuru.com website which focuses on performance tuning UNIX-like Operating Systems (including Linux).
As threading seems to be flavour of the month I would recommend this article
in ACM Queue
. The article looks at the locking complexities that arise from preemptive scheduling of threads and introduces a stateless threading library that can be used to avoid the use of mutex structures and other complex locking primitives.
Got some ideas going about Xen, I/O spaces and simplifying the Operating System...