Power-dissipation comparison of two dependability approaches for multi-processor systems

The additional power dissipation involved in introducing a high dependability in multi-processor systems is nowadays becoming a major concern (power-aware dependability). In this paper, the power dissipation components of a recently implemented scan-test based dependability testing approach for a multi-processor Systems-on-Chip (SoC) is evaluated. It is shown that the application of scan-test vectors to the cores is the major power contributor. To avoid this dissipation and hence scan test, a new prognostic approach for life-time prediction using on-line health monitors is proposed accomplishing the same high dependability. It will be shown that the latter approach consumes less power under the same dependability specifications. Actual measurements and theoretical calculations are provided as well as a suggestion for future dependable systems given.