OS-Controlled Cache Predictability for Real-Time Systems

  • Autor:

    Jochen Liedtke, Hermann Härtig, and Michael Hohmuth

  • Quelle:

    Proceedings of the 3rd IEEE Real-time Technology and Applications Symposium (RTAS), Montreal, Canada, June 1997

  • Datum: 06.1997
  • Abstract:

    Cache-partitioning techniques have been invented to make modern processors with an extensive cache structure useful in real-time systems where task switches disrupt cache working sets and hence make execution times unpredictable. This paper describes an OS-controlled applicationtransparent cache-partitioning technique. The resulting partitions can be transparently assigned to tasks for their exclusive use. The major drawbacks found in other cachepartitioning techniques, namely waste of memory and additions on the critical performance path within CPUs, are avoided using memory coloring techniques that do not require changes within the chips of modern CPUs or on the critical path for performance. A simple filter algorithm commonly used in real-time systems, a matrixmultiplication algorithm and the interaction of both are analysed with regard to cache-induced worst case penalties. Worst-case penalties are determined for different widely-used cache architectures. Some insights regarding the impact of cache architectures on worst-case execution are described.


      author = {Jochen Liedtke and Hermann H\"artig and Michael Hohmuth},
      title = {OS-Controlled Cache Predictability},
      booktitle = {Proceedings of the 3rs IEEE Real-time Technology and Applications Symposium (RTAS)},
      address = {Montreal, Canada},
      month = jun,
      year = 1997,
      url = {http://l4ka.org/publications/}