Warp: A Hardware Platform for Efficient Multi- Modal Sensing with Adaptive Approximation

We present Warp, the first open hardware platform designed explicitly to support research in approximate computing. Warp incorporates 21 sensors, computation, and circuit-level facilities designed explicitly to enable approximate computing research, in a 3.6 cm×3.3 cm×0.5 cm area. Warp uses these facilities to support a wide range of precision and accuracy versus power and performance tradeoffs

Warp: A Hardware Platform for Efficient Multi- Modal Sensing with Adaptive Approximation

We present Warp, the first open hardware platform designed explicitly to support research in approximate computing. Warp incorporates 21 sensors, computation, and circuit-level facilities designed explicitly to enable approximate computing research, in a 3.6 cm×3.3 cm×0.5 cm area. Warp uses these facilities to support a wide range of precision and accuracy versus power and performance tradeoffs

SibylFS: Formal specification and oracle-based testing for POSIX and real-world file systems

Systems depend critically on the behaviour of file systems, but that behaviour differs in many details, both between implementations and between each implementation and the POSIX (and other) prose specifications. Building robust and portable software requires understanding these details and differences, but there is currently no good way to systematically describe, investigate, or test file system behaviour across this complex multi-platform interface. In this paper we show how to characterise the envelope of allowed behaviour of file systems in a form that enables practical and highly discriminating testing. We give a mathematically rigorous model of file system behaviour, SibylFS, that specifies the range of allowed behaviours of a file system for any sequence of the system calls within our scope, and that can be used as a test oracle to decide whether an observed trace is allowed by the model, both for validating the model and for testing file systems against it. SibylFS is modular enough to not only describe POSIX, but also specific Linux, OS X and FreeBSD behaviours. We complement the model with an extensive test suite of over 21 000 tests; this can be run on a target file system and checked in less than 5 minutes, making it usable in practice. Finally, we report experimental results for around 40 configurations of many file systems, identifying many differences and some serious flaws

No Provisioned Concurrency: Fast RDMA-codesigned Remote Fork for Serverless Computing

Serverless platforms essentially face a tradeoff between container startup time and provisioned concurrency (i.e., cached instances), which is further exaggerated by the frequent need for remote container initialization. This paper presents MITOSIS, an operating system primitive that provides fast remote fork, which exploits a deep codesign of the OS kernel with RDMA. By leveraging the fast remote read capability of RDMA and partial state transfer across serverless containers, MITOSIS bridges the performance gap between local and remote container initialization. MITOSIS is the first to fork over 10,000 new containers from one instance across multiple machines within a second, while allowing the new containers to efficiently transfer the pre-materialized states of the forked one. We have implemented MITOSIS on Linux and integrated it with FN, a popular serverless platform. Under load spikes in real-world serverless workloads, MITOSIS reduces the function tail latency by 89% with orders of magnitude lower memory usage. For serverless workflow that requires state transfer, MITOSIS improves its execution time by 86%.Comment: To appear in OSDI'2