The Case for a Factored Operating System (fos)

The next decade will afford us computer chips with 1,000 - 10,000 cores on a single piece of silicon. Contemporary operating systems have been designed to operate on a single core or small number of cores and hence are not well suited to manage and provide operating system services at such large scale. Managing 10,000 cores is so fundamentally different from managing two cores that the traditional evolutionary approach of operating system optimization will cease to work. The fundamental design of operating systems and operating system data structures must be rethought. This work begins by documenting the scalability problems of contemporary operating systems. These studies are used to motivate the design of a factored operating system (fos). fos is a new operating system targeting 1000+ core multicore systems where space sharing replaces traditional time sharing to increase scalability. fos is built as a collection of Internet inspired services. Each operating system service is factored into a fleet of communicating servers which in aggregate implement a system service. These servers are designed much in the way that distributed Internet services are designed, but instead of providing high level Internet services, these servers provide traditional kernel services and manage traditional kernel data structures in a factored, spatially distributed manner. The servers are bound to distinct processing cores and by doing so do not fight with end user applications for implicit resources such as TLBs and caches. Also, spatial distribution of these OS services facilitates locality as many operations only need to communicate with the nearest server for a given service

On the Performance and Isolation of Asymmetric Microkernel Design for Lightweight Manycores

International audienc

A Unified Operating System for Clouds and Manycore: fos

Single chip processors with thousands of cores will be available in the next ten years and clouds of multicore processors afford the operating system designer thousands of cores today. Constructing operating systems for manycore and cloud systems face similar challenges. This work identifies these shared challenges and introduces our solution: a factored operating system (fos) designed to meet the scalability, faultiness, variability of demand, and programming challenges of OSâ s for single-chip thousand-core manycore systems as well as current day cloud computers. Current monolithic operating systems are not well suited for manycores and clouds as they have taken an evolutionary approach to scaling such as adding fine grain locks and redesigning subsystems, however these approaches do not increase scalability quickly enough. fos addresses the OS scalability challenge by using a message passing design and is composed out of a collection of Internet inspired servers. Each operating system service is factored into a set of communicating servers which in aggregate implement a system service. These servers are designed much in the way that distributed Internet services are designed, but provide traditional kernel services instead of Internet services. Also, fos embraces the elasticity of cloud and manycore platforms by adapting resource utilization to match demand. fos facilitates writing applications across the cloud by providing a single system image across both future 1000+ core manycores and current day Infrastructure as a Service cloud computers. In contrast, current cloud environments do not provide a single system image and introduce complexity for the user by requiring different programming models for intra- vs inter-machine communication, and by requiring the use of non-OS standard management tools

Fleets: Scalable Services in a Factored Operating System

Current monolithic operating systems are designed for uniprocessor systems, and their architecture reflects this. The rise of multicore and cloud computing is drastically changing the tradeoffs in operating system design. The culture of scarce computational resources is being replaced with one of abundant cores, where spatial layout of processes supplants time multiplexing as the primary scheduling concern. Efforts to parallelize monolithic kernels have been difficult and only marginally successful, and new approaches are needed. This paper presents fleets, a novel way of constructing scalable OS services. With fleets, traditional OS services are factored out of the kernel and moved into user space, where they are further parallelized into a distributed set of concurrent, message-passing servers. We evaluate fleets within fos, a new factored operating system designed from the ground up with scalability as the first-order design constraint. This paper details the main design principles of fleets, and how the system architecture of fos enables their construction. We describe the design and implementation of three critical fleets (network stack, page allocation, and file system) and compare with Linux. These comparisons show that fos achieves superior performance and has better scalability than Linux for large multicores; at 32 cores, fos's page allocator performs 4.5 times better than Linux, and fos's network stack performs 2.5 times better. Additionally, we demonstrate how fleets can adapt to changing resource demand, and the importance of spatial scheduling for good performance in multicores

A review on Reliability, Security and Memory Management of Numerous Operating Systems

With the improvement of technology and the growing needs of computer systems, it is needed to ensure that operating systems are able to provide the required functionalities. To provide these functionality operating systems are designed to maintain some design factors such as scalability, security, reliability, performance, memory management, energy efficiency. However, none of these factors can be achieved directly without facing any challenges. This research studied several design issues that are connected to each other in terms of providing an effective result. Therefore, this review article tried to reveal the major issues, which are independently more complex to solve at once. Finally, this research provides a guideline to overcome the challenges for future researchers by studying many research articles based on these design issues

Secure Virtualization and Multicore Platforms State-of-the-Art report

SVaM

seL4 Microkernel for virtualization use-cases: Potential directions towards a standard VMM

Virtualization plays an essential role in providing security to computational systems by isolating execution environments. Many software solutions, called hypervisors, have been proposed to provide virtualization capabilities. However, only a few were designed for being deployed at the edge of the network, in devices with fewer computation resources when compared with servers in the Cloud. Among the few lightweight software that can play the hypervisor role, seL4 stands out by providing a small Trusted Computing Base and formally verified components, enhancing its security. Despite today being more than a decade with seL4 microkernel technology, its existing userland and tools are still scarce and not very mature. Over the last few years, the main effort has been put into increasing the maturity of the kernel itself and not the tools and applications that can be hosted on top. Therefore, it currently lacks proper support for a full-featured userland Virtual Machine Monitor, and the existing one is quite fragmented. This article discusses the potential directions to a standard VMM by presenting our view of design principles and feature set needed. This article does not intend to define a standard VMM, we intend to instigate this discussion through the seL4 community

A communication framework for distributed access control in microkernel-based systems

Microkernel-based architectures have gained an increasing interest and relevance for embedded systems. These can not only provide real-time guarantees but also offer strong security properties which become increasingly significant in certain application domains such as automotive systems. Nevertheless, the functionality of those complex systems often needs to be distributed across a network of control units for various reasons (e.g. physical location, scalability, separation). Although microkernels have been commercially established, distributed systems like these have not been a major focus. This is basically originated by the fact that – in the microkernel world – policy, device drivers and protocol stacks are userspace concerns and rather left to be solved by the particular application domain. Following the principle of least privilege, we therefore developed a distributed access-control framework for all network-based communication in microkernel-based systems that can be generically deployed. Our design not only enforces security properties such as integrity but is also scalable without adding too much overhead in terms of run time or code