Design and Implementation of the Multiprocessor Bandwidth Inheritance Protocol on Linux

The Multiprocessor Bandwidth Inheritance (M-BWI) is a synchronisation protocol for coordinating mutually exclusive access to critical sections in multi-processor real-time systems. It combines resource reservations techniques with the priority inheritance access protocol, so to guarantee temporal isolation between non-interacting tasks and real-time execution. In the original paper, the authors proposed an implementation in LITMUS-RT, a version of Linux specifically designed for research purposes. In this paper we propose an implementation of the M-BWI protocol on the Linux OS augmented with the SCHED DEADLINE patch. We describe the architecture of our implementation, highlighting the problems we found and the possible solutions. We also run an extensive set of experiments for evaluating the overhead of the proposed implementation.