The global deadline scheduler patchset for Linux SCHED_DEADLINE (implementing Earliest Deadline First and Constant Bandwidth Server real-time scheduling algorithms) has been exploited to investigate on pros and cons of different approaches to real-time scheduling on big multi-core systems. Researchers at SSSA published a journal paper in which an experimental comparison among the Rate Monotonic (RM) and Earliest Deadline First (EDF) multi-core real-time schedulers is performed, with a focus on soft real-time systems.

The designer of a real-time system often needs to compare different available real-time scheduling strategies, in terms of their impact on the performance of the hosted applications.

The Linux Plumbers Conference is a forum, with strong technical focus, that spurs communication and problem-solving for system-wide issues crossing project and business boundaries. Every year it brings together highly skilled Linux developers from all over the world setting the ground for next year advancements of the low level Linux infrastructure. This year the S(o)OS project has participated with a talk by Juri Lelli from SSSA with title “SCHED_DEADLINE (what it does and doesn't do.. yet)”.

The memory wall problem cannot be overcome by new operating systems or infrastructures alone, if the application is not properly prepared for it, i.e. if the data dependencies are not properly identified and treated in the program itself. Classical programming models are not aligned to this problem and hence make it difficult for compilers and the operating system to properly analyse the data dependency and to adjust accordingly.

Within the S(o)OS project, a new programming concept exploiting data flow information inherent to mathematical description has been proposed to address this problem.

The S(o)OS project primarily focused on generating a suitable architecture for future operating system, but did not have the resources to implement a working kernel. Instead, it generated the necessary set of algorithms, interfaces and protocol descriptions, preparing an implementation as much as possible and allowing evaluation of behaviour and performance.

As the impact of the memory wall increases, new methods are needed to better exploit the available storage and reduce the amount of cache misses. Traditional monolithic operating systems are not ready for this move, since they create considerable overhead on cache and data communication. Within its 3 years runtime, the S(o)OS project investigated, how operating systems need to change in order to offer the necessary performance in future systems. The result of this investigation consisted in a modular architecture that is highly promising for large scale applications dedicated to specific tasks, such as video stream processing, fluid dynamics simulation etc.

A new SoOSiM installation guide have been published for all those interested in trying out this Operating Simulator that has been helping developing the S(o)OS architecture. If you are interested visit the SoOSiM installation guide.

The global EDF real-time Linux scheduler extension SCHED_DEADLINE has been presented by Juri Lelli (of Scuola Superiore Sant'Anna of Pisa) at the last Linux Plumbers Conference (LPC'12) in San Diego. The talk originated an interesting discussion among possible users of the patchset. The intention of merging the code inside the stock Linux kernel has been confirmed by the scheduler maintainers that were present at the discussion.

The second issue of the S(o)OS Newsletter is out. The newsletter has the purpose of spreading the word about the research issues that are being investigated in the project and the approach we are following for addressing them.

Modern IT infrastructures constantly increase in scale, heterogeneity and complexity. With the introduction of the many core processor, even the average personal computer has been turned into a parallel machine, thus giving rise to a complete new computing paradigm - yet we still treat computers like a single von Neumann instance.