Microkernel operating systems (OSes) use zero-copy communication to reduce the overhead of copying transfer data, because the communication between OS servers occurs frequently in the case of microkernel OSes. However, when a memory management unit manages the translation lookaside buffer (TLB) using software, TLB misses tend to increase the overhead of interprocess communication (IPC) between OS servers running on a microkernel OS. Thus, improving the control method of a software-managed TLB is important for microkernel OSes. This paper proposes a fast control method of software-managed TLB that manages page attachment in the area used for IPC by using TLB entries, instead of page tables. Consequently, TLB misses can be avoided in the area, and the performance of IPC improves. Thus, taking the SH-4 processor as an example of a processor having a software-managed TLB, this paper describes the design and the implementation of the proposed method for AnT operating system, and reports the evaluation results of the proposed method.

The emerging discipline of responsive systems demands fault-tolerant and real-time performance in uniprocessor, parallel, and distributed computing environments. The new proposal for responsiveness measure is presented, followed by an introduction of a model for responsive computing. The model, called CONCORDS (CONsensus/COmputation for Responsive Distributed Systems), is based on the integration of various forms of consensus and computation (progress or recovery). The consensus tasks include clock synchronization, diagnosis, checkpointing scheduling and resource allocation.