A tuneable software cache coherence protocol for heterogeneous MPSoCs

Frank Ophelders, Marco Jan Gerrit Bekooij, Henk Corporaal

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    5 Citations (Scopus)

    Abstract

    In a multiprocessor system-on-chip (MPSoC) private caches introduce the cache coherence problem. Here, we target at heterogeneous MPSoCs with a network-on-chip (NoC). Existing hardware cache coherence protocols are less suitable for MPSoCs because many off-the-shelf processors used in MPSoCs do not support these protocols. Furthermore, these protocols typically rely on global visibility and serialization of writes which does not match well with the parallel point-to-point communication provided by a NoC. Therefore, we propose a software cache coherence protocol, which can be applied in a heterogeneous MPSoC with a NoC. The software cache coherence protocol relies on explicit synchronization in the software. More specifically, caches are guaranteed to be coherent according to the Release Consistency model, on top of which we have implemented the standard Pthreads communication library. Heterogeneous MPSoCs with off-the-shelf processors can easily be supported, because processors are only required to provide cache control operations, e.g., clean and invalidate. All cache coherence operations are interruptible and do not impact the execution of tasks on other processors, therefore this protocol is suitable for predictable MPSoCs. Our software cache coherence protocol is implemented on an ARM926EJ-S MPSoC which is mapped on an FPGA. From experiments we conclude that the protocol overhead is low for the applications taken from the SPLASH-2 benchmark set. For these applications we observed a speedup between 1.89 and 2.01 on the two processor MPSoC.
    Original languageUndefined
    Title of host publicationProceedings of the 7th IEEE/ACM International Conference on Hardware/Software Codesign and System Synthesis
    Place of PublicationNew York
    PublisherAssociation for Computing Machinery (ACM)
    Pages383-392
    Number of pages10
    ISBN (Print)978-1-60558-628-1
    DOIs
    Publication statusPublished - 12 Oct 2009
    Event7th IEEE/ACM International conference on Hardware/Software codesign and system synthesis, Grenoble, France: Proceedings of the 7th IEEE/ACM International conference on Hardware/Software codesign and system synthesis - New York
    Duration: 12 Oct 2009 → …

    Publication series

    Name
    PublisherACM

    Conference

    Conference7th IEEE/ACM International conference on Hardware/Software codesign and system synthesis, Grenoble, France
    CityNew York
    Period12/10/09 → …

    Keywords

    • METIS-264474
    • EWI-17189
    • IR-69791

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