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Announcement - Agenda - Paper Presentations

Increasing interest for real-time support in general purpose operating systems has driven a lot of development efforts inside the Linux kernel community. Thus, a Linux based system may be a suitable platform to run heterogeneous real-time and non real-time, periodic and aperiodic applications. Linux is a POSIX/Unix-like system, so real-time tasks are supported by means of the well established and powerful techniques of fixed priority preemptive scheduling. When dealing with real-time aperiodic tasks under fixed priority scheduling, an effective mechanism that provides fast response time without affecting the scheduling of the periodic tasks is the Sporadic Server. Such an algorithm is also part of the POSIX real-time extensions, but it is not yet supported by the Linux kernel.

For all these reasons, we implemented the POSIX SCHED_SPORADIC scheduling policy in the Linux kernel, after having extended it to support hierarchical scheduling. Moreover, since we think this could be a useful feature, we are also submitting it to the community, asking for inclusion in the mainline kernel distribution. In this paper we describe our motivations, the implementation and some preliminary experimental results.