Future Technologies Colloquium Series

ABSTRACT:

Modern computing systems become increasingly data-driven. Concurrent I/O is a commonplace in data-intensive server systems and parallel computing systems. In this talk, I will introduce two techniques we proposed for improving OS support for concurrent I/O. First, during concurrent I/O workloads, frequent disk head switching between multiple I/O streams may severely affect I/O efficiency. Aggressive prefetching can improve the granularity of sequential data access, but it comes with a higher risk of fetching unneeded data. We propose a competitive prefetching strategy that controls prefetching depth so that the overhead of disk I/O switch and unnecessary prefetching are balanced. Second, concurrent I/O systems may contain a large amount of prefetched data in memory. Traditional access-history based page reclamation methods are not effective for prefetched pages. We propose a heuristic-based OS-level scheme that can manage prefetch memory more efficiently.

Beyond this work, I will also briefly introduce some of my other research efforts with my colleagues, including I/O system performance debugging and operating system exploitation of processor hardware event counters.