Challenges of safety-critical multi-core systems

Chris Ault, Wind River
EETimes (4/23/2011 10:59 PM EDT )

Many embedded systems are realizing the benefits of multi-core CPUs. These benefits include the ability to consolidate multiple distinct hardware boards on a single CPU, the ability to deliver more performance per Watt, as well as ability to quickly migrate existing designs to new processors and then use the additional compute power to implement new functionality.

These benefits are also very enticing to projects that are building embedded systems specifically for the safety critical market. However, these systems have their own challenges with regards to safety certification. Ideally, safety systems would like to reap the same benefits (consolidation, performance, migration), while keeping certification costs as low as possible.

One particular attractive scenario for safety critical systems is to combine a certified subsystem, such as robot-control spplication, with a non-certified subsystem, perhaps a Linux or MS Windows based human machine interface. The challenge in this scenario is certification of the complete product.

The challenges of multi-core CPUs include interrupt handling, bus contention, and increased coding and debugging complexities; there are hardware devices on the CPU that cannot be shared among safety-certified and general-purpose applications.

By having the ability to partition the devices and present specific devices to certain cores and applications these challenges can be mitigated, and the benefits of multi-core can be realized. Complicated software can be used for this partitioning and isolation, but embedded virtualization offers a configurable means by which devices can be partitioned and presented to specific cores, operating systems, and applications.

Code footprint directly impacts certification costs. Choosing an embedded virtualization solution with minimal code footprint will minimize recertification costs and maintain the real-time responsiveness of a device. Choosing a safety-certified virtualization solution will ensure that the complete application stack can be safety certified.

This paper will explore the benefits of virtualization to safety critical systems and explore some of the challenges and how to mitigate the risks associated with them.

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