Energy-aware memory firewalling for QoS-sensitive applications

This paper presents operating system abstractions for managing physical memory and paging that can be used to improve both timing predictability and the run-time performance of soft real-time tasks. First, we propose a memory reservation scheme which allows any application to reserve a portion of the total system memory pages for its exclusive use. If the application\´s memory needs exceed its memory reservation, its pages are swapped within its own reservation, thereby containing the performance effects of its memory access profile to its reservation. Swap space for the application is also reserved. A memory reservation can be shared by multiple threads/applications, and reservations can be used hierarchically, with children using only a portion of their parent\´s reservation. Next, we propose a novel methodology to determine reservation sizes for an embedded task-set that optimizes the overall performance of the system. We also show how an application can leverage customized predictable page-replacement policies to minimize performance penalties from avoidable page faults ("capacity misses").