CPU scheduling and memory management for interactive real-time applications

摘要

In this paper, we propose, design, implement, and evaluate a CPU scheduler and a memory management scheme for interactive soft real-time applications. Our CPU scheduler provides a new CPU reservation algorithm that is based on the well-known Constant Bandwidth Server (CBS) algorithm but is more flexible in allocating the CPU time to multiple concurrently-executing real-time applications. Our CPU scheduler also employs a new multicore scheduling algorithm, extending the Earliest Deadline First to yield Window-constraint Migrations (EDF-WM) algorithm, to improve the absolute CPU bandwidth available in reservation-based systems. Furthermore, we propose a memory reservation mechanism incorporating a new paging algorithm, called Private-Shared-Anonymous Paging (PSAP). This PSAP algorithm allows interactive real-time applications to be responsive under memory pressure without wasting and compromising the memory resource available for contending best-effort applications. Our evaluation demonstrates that our CPU scheduler enables the simultaneous playback of multiple movies to perform at the stable frame-rates more than existing real-time CPU schedulers, while also improves the ratio of hard-deadline guarantee for randomly-generated task sets. Furthermore, we show that our memory management scheme can protect the simultaneous playback of multiple movies from the interference introduced by memory pressure, whereas these movies can become unresponsive under existing memory management schemes.