A Real-Time Linux for Multicore Platforms

Abstract : The objective of this project is to extend a prototype Linux-based real-time operating system developed previously at UNC (under ARO support) to obtain a fully-functional OS for supporting real-time workloads on multicore platforms. This system, called LITMUS-RT (LInux Testbed for MUltiprocessor Scheduling in Real-Time systems), allows different multiprocessor real-time scheduling and synchronization policies to be specified as plugin components. LITMUS-RT is open-source software (available at http://www.litmus-rt.org). The pre-existing LITMUS-RT implementation included plugins for several real-time scheduling and synchronization policies. However, as its name suggests, LITMUS-RT was originally designed as a testbed for empirically comparing such policies. Extending LITMUS-RT so that it can host real applications will require extensions on several fronts. These include: (i) new synchronization and scheduling algorithms that are better suited for large multicore platforms; (ii) new analysis and implementation methods for dealing with non-CPU resources such as graphics processing units (GPUs); (iii) support for dynamic task behavior (tasks can be created, destroyed, and their timing parameters altered at runtime); and (iv) mechanisms for supporting precedence constraints and task suspensions (e.g., due to I/O). The research in this project has led to several joint efforts with colleagues in industry and government labs involving military avionics.