A Closer Look at Intel Resource Director Technology (RDT).

Unarbitrated contention over shared resources at different levels of the memory hierarchy represents a major source of temporal interference. Hardware manufacturers are increasingly more receptive to issues with temporal interference and are starting to propose concrete solutions to mitigate the problem. Intel Resource Director Technology (RDT) represents one such attempt. Given the wide adoption of Intel platforms, RDT features can be an invaluable asset for the consolidation of real-time systems on complex multi- and many-core machines. Unfortunately, to date, a systematic analysis of the capabilities introduced by the RDT framework has not yet been conducted. Moreover, no clear understanding has been matured about the implementation-specific behavior of RDT primitives across processor generations. And ultimately, the ability of RDT to provide real-time guarantees is yet to be established. In our work, we aim at conducting a systematic investigation of the RDT mechanisms from a real-time perspective. We experimentally evaluate the functionality and interpretability of RDT-aided allocation and monitoring controls across the two most recent processor generations. Our evaluations show that while some features like Cache Allocation Technology (CAT) yield promising results, the implementation of other primitives such as Memory Bandwidth Allocation (MBA) has much room for improvement. Moreover, in some cases, the presented interfaces range from blurry to incomplete, as is the case for MBA and Memory Bandwidth Monitoring (MBM).