Contributions

In summary, the contributions of this paper are as follows:

• We introduce Semi-preemptible IO, which abstracts both read and write IO requests so as to make them preemptible. As a result, system can substantially reduce the waiting time for a higher-priority request at little or no extra cost.
• We show that making write IOs preemptible is not as straightforward as it is for read IOs. We propose one possible solution for making them preemptible.
• We present a feasible path to implement Semi-preemptible IO. We explain how the implementation is made possible through use of a detailed disk profiling tool.

The rest of this paper is organized as follows: Section 2 presents related research. Section 3 introduces Semi-preemptible IO and describes its three components. In Section 4, we evaluate our prototype. In Section 5, we make concluding remarks and suggest directions for future work.