Predictable Code and Data Paging for Real Time Systems

There is a need for using virtual memory in real-time applications: using virtual addressing provides isolation between concurrent processes; in addition, paging allows the execution of applications whose size is larger than main memory capacity, which is useful in embedded systems where main memory is expensive and thus scarce. However, virtual memory is generally avoided when developing real-time and embedded applications due to predictability issues. In this paper we propose a predictable paging system in which the page loading and page eviction points are selected at compile-time. The contents of main memory is selected using an Integer Linear Programming (ILP) formulation. Our approach is applied to code, static data and stack regions of individual tasks. We show that the time required for selecting memory contents is reasonable for all applications including the largest ones, demonstrating the scalability of our approach. Experimental results compare our approach with a previous...

• Type: Conference
• Year: 2008
• Where: ECRTS
• Authors: Damien Hardy, Isabelle Puaut
• Keywords: ECRTS 2008, Embedded Systems, Main Memory, Main Memory Capacity, Virtual Memory