A practical solution for functional reconfiguration of real-time service based applications through partial schedulability

REACTION 2012. 1st International workshop on Real-time and distributed computing in emerging applications. December 4th, 2012, San Juan, Puerto Rico.Timely reconfiguration in distributed real-time systems is a complex problem with many sides to it ranging from system-wide concerns down to the intrinsic non-robust nature of the specific middleware software and the used programming techniques. In an completely open distributed system, it is not possible to achieve time-deterministic functional reconfiguration; the set of possible target configurations that the system can transition to could be extremely large threatening the temporal predictability of the reconfiguration process. Therefore, a set of bounds and limitations to the structure of systems and to their open nature need to be imposed. In this paper, we present the different sides of the problem of reconfiguration. We provide a solution for timely reconfiguration based on reducing the solution space of solutions of partially closed applications; we have enhanced the logic of a middleware for distributed soft real-time applications with the proposed technique. As a result, applications require a limited number of schedulability tests to search for the valid target configuration. We present some results on the actual reduction of the configuration space achieved by our middleware.This work has been partly supported by the iLAND project (ARTEMISJU 100026) funded by the ARTEMIS JTU Call 1 and the Spanish Ministry of Industry (www.iland-artemis.org), ARTISTDesign NoE (IST-2007- 214373) of the EU 7th Framework Programme, and by the Spanish national project REM4VSS (TIN 2011-28339)