Compensating for Timing Jitter in Computing Systems with General-Purpose Operating Systems

Fault-tolerant frameworks for large scale computing clusters require sensor programs, which are executed pe-riodically to facilitate performance and fault management. By construction, these clusters use general purpose oper-ating systems such as Linux that are built for best average case performance and do not provide deterministic schedul-ing guarantees. Consequently, periodic applications show jitter in execution times relative to the expected execution time. Obtaining a deterministic schedule for periodic tasks in general purpose operating systems is difficult without us-ing kernel-level modifications such as RTAI and RTLinux. However, due to performance and administrative issues ker-nel modification cannot be used in all scenarios. In this paper, we address the problem of jitter compensation for periodic tasks that cannot rely on modifying the operating system kernel.; Towards that, (a) we present motivating examples; (b) we present a feedback controller based ap-proach that runs in the user space and actively compen-sates periodic schedule based on past jitter; This approach is platform-agnostic i.e. it can be used in different operat-ing systems without modification; and (c) we show through analysis and experiments that this approach is platform-agnostic i.e. it can be used in different operating systems without modification and also that it maintains a stable sys-tem with bounded total jitter. 1