A Prioritized Cache for Multi- tasking Real-time Systems

In this paper, we present a new prioritized cache which can reduce the Worst Case Cache Miss Rate (WCCMR) of an application in a multi-tasking environment. The Worst Case Execution Ti me (WCET) can be estimated more precisely when the cache miss rate has a stable and low upper bound. An experiment in which a MPEG decoder and a Mobile Robot (MR) control program are executed alternatively shows that we can achieve a nearly constant cache miss rate with our method. The cache miss rate of the time critical application (MR) varies from 45% to 15% with a normal cache, while with a prioritized cache the cache miss rate is always less than 13%, a 3X reduction. With this lower WCCMR, we achieve a much tighter WCET estimate, 41% lower in fact, for MR in this

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