Redline: First Class Support for Interactivity in Commodity Operating Systems

         While modern workloads are increasingly interactive and resource-intensive (e.g., graphical user interfaces, browsers, and multimedia players), current operating systems have not kept up. These operating systems, which evolved from core designs that date to the 1970s and 1980s, provide good support for batch and command-line applications but do little to ensure responsiveness. Despite of their best-effort priority-based schedulers that provide no bounds on delays, their resource managers (especially memory managers, disk I/O schedulers) are completely oblivious to response time requirements. Therefore, pressure on any of these resources can significantly degrade application responsiveness.

We present Redline, a system that brings first-class support for interactive applications to commodity operating systems. Redline works with unaltered applications and standard APIs. It uses lightweight specifications to orchestrate memory and disk I/O management to
serve the needs of interactive applications. Unlike real-time systems that treat specifications as strict requirements and thus pessimistically limit system utilization, Redline dynamically adapts to load to maximize responsiveness and system utilization. We show that Redline delivers responsiveness to interactive applications even in the face of extreme workloads including fork bombs, malloc bombs and bursty large disk I/O requests, reducing application pauses by up to two orders of magnitude.