Nick Piggin, a college student living in Canberra Australia, has been working on an anticipatory I/O scheduler for the Linux kernel [story].

When a process reads data from a disk, the default "deadline" I/O scheduler can offer poor performance if a streamed write is happening at the same time. The reason is that many read operations require multiple reads, each reporting a result back before the next can be scheduled. Thus, each of these reads has to wait behind a queue of writes, resulting in the aforementioned performance problem. The anticipatory scheduler solves this problem nicely by pausing for a few milliseconds after each read, "anticipating" the next read request [story].

In this interview, Nick offers much more detail behind the operation of the anticipatory scheduler. His goal is to stablize and tune [story] the new scheduler, aiming utimately for inclusion into the 2.5 development kernel tree as the default Linux I/O scheduler [story]. The latest version of Nick's anticipatory scheduler can be found here in Andrew Morton's [interview] -mm kernel branch.