We present RSIO, a processor scheduling framework for improving the response time of latency-sensitive applications by monitoring accesses to I/O channels and inferring when user interactions occur. RSIO automatically identifies processes involved in a user interaction and boosts their priorities at the time the interaction occurs to improve system response time. RSIO also detects processes indirectly involved in processing an interaction, automatically accounting for dependencies and boosting their priorities accordingly. RSIO works with existing schedulers and requires no application modifications to identify periods of latencysensitive application activity. We have implemented RSIO in Linux and measured its effectiveness on microbenchmarks and real applications. Our results show that RSIO is easy to use and can provide substantial improvements in system performance for latency-sensitive applications. Categories and Subject Descriptors: D.4.1 [Operating Systems]: Process Manageme...