Quasi Isolation QoS Setups to Control MPSoC Contention in Integrated Software Architectures

The use of integrated architectures, such as integrated modular avionics (IMA) in avionics, IMA-SP in space, and AUTOSAR in automotive, running on Multi-Processor System-on-Chip (MPSoC) is on the rise. Timing isolation among the different software partitions or applications thereof in an integrated architecture is key to simplifying software integration and its timing validation by ensuring the performance of each partition has no or very limited impact on others despite they share MPSoC’s hardware resources. In this work, we contend that the increasing hardware support for Quality of Service (QoS) guarantees in modern MPSoCs can be leveraged via specific setups to provide strong, albeit not full, isolation among different software partitions. We introduce the concept of Quasi Isolation QoS (QIQoS) setups and instantiate it in the Xilinx Zynq UltraScale+. To that end, out of the millions of setups offered by the different QoS mechanisms, we identify specific QoS configurations that isolate the traffic of time-critical software partitions executing in the core cluster from that generated by contender partitions in the programmable logic. Our results show that the selected isolation setup results in performance variations of the partitions run in the computing cores that are below 6 percentage points, even under scenarios with extremely high traffic coming from the programmable logic.