BlueIO

Abstract

In safety-critical systems, time predictability is vital. This extends to I/O operations that require predictability, timing-accuracy, parallel access, scalability, and isolation. Currently, existing approaches cannot achieve all these requirements at the same time. In this article, we propose a framework of hardware framework for real-time I/O virtualization—termed BlueIO —to meet all these requirements simultaneously. BlueIO integrates the functionalities of I/O virtualization, low-layer I/O drivers, and a clock cycle level timing-accurate I/O controller (using the GPIOCP [36]). BlueIO provides this functionality in the hardware layer, supporting abstract virtualized access to I/O from the software domain. The hardware implementation includes I/O virtualization and I/O drivers, provides isolation and parallel (concurrent) access to I/O operations, and improves I/O performance. Furthermore, the approach includes the previously proposed GPIOCP to guarantee that I/O operations will occur at a specific clock cycle (i.e., be timing-accurate and predictable). In this article, we present a hardware consumption analysis of BlueIO to show that it linearly scales with the number of CPUs and I/O devices, which is evidenced by our implementation in VLSI and FPGA. We also describe the design and implementation of BlueIO and demonstrate how a BlueIO-based system can be exploited to meet real-time requirements with significant improvements in I/O performance and a low running cost on different OSs.