Attacking the one-out-of-m multicore problem by combining hardware management with mixed-criticality provisioning

The multicore revolution is having limited impact in safety-critical application domains. A key reason is the “one-out-of-m ” problem: when validating real-time constraints on an m-core platform, excessive analysis pessimism can effec-tively negate the processing capacity of the additional m − 1 cores so that only “one core’s worth ” of capacity is avail-able. Two approaches have been investigated previously to address this problem: mixed-criticality allocation techniques, which provision less-critical software components less pes-simistically, and hardware-management techniques, which make the underlying platform itself more predictable. A bet-ter way forward may be to combine both approaches, but to show this, fundamentally new criticality-cognizant hardware-management tradeoffs must be explored. Such tradeoffs are investigated herein in the context of a large-scale, overhead-aware schedulability study. This study was guided by exten-sive trace data obtained by executing benchmark tasks on a new variant of the MC2 framework that supports config-urable criticality-based hardware management. This study shows that the two approaches mentioned above can be much more effective when applied together instead of alone.