SHRED: a CPU scheduler for heterogeneous applications

General purpose workstations must support a wide variety of application characteristics; but it is hard to find a single CPU scheduling scheme that satisfactorily schedules processes from all types of applications. It is particularly difficult to get periodic deadline-driven continuous media processes to satisfactorily co-exist with others. A number of schemes have been proposed to address this issue, but these all suffer from one or more of the following limitations: i) unacceptable inefficiency, ii) non-determinism (i.e. introducing significant burstiness or jitter), iii) inability to explicitly support deadlines (so that deadlines may be missed even when the CPU is underloaded). This paper presents "SHRED (SHaretokens, Round-robin, Earliest-deadline-first, Deferred-processing)"-an efficient, proportional-share, deterministic, scheduling scheme that enables periodic deadline-driven processes to meet their explicit deadlines wherever possible, and degrades gracefully and adaptively when this is not possible. The scheme simultaneously ensures that non-deadline processes always obtain their fair share of CPU time whether in conditions of underload or overload. For experimental evaluation, a prototype of SHRED has been developed by replacing the Linux standard scheduler with the SHRED scheduler. The prototype has been evaluated against the standard Linux scheduler for various parameters and also against two proportional-share schemes, namely Stride and VTRR scheduling, for its overhead and its effect on jitter

A retrospective on the design of the GOPI middleware platform

This paper offers a high-level retrospective overview of the GOPI middleware platform which is the outcome of a three-year project aimed at the development of generic, configurable and extensible middleware. GOPI has a clearly defined modular structure, is widely extensible with plug-ins at all levels of the architecture, and natively supports stream interactions as well as standard operation invocation. It offers a generic framework for quality of service (QoS) specification and management, and supports a high-level, multimedia-oriented programming environment that is backwardly compatible with the OMG's CORBA. At its lower levels it supports QoS-driven resource management and features an optimised HOP stack. Despite its enhanced functionality, GOPI's HOP performance equals or exceeds that of state-of-the-art CORBA platforms

IPV6 Deployment - Mauritius to benefit from Opportunities and World-wide Experiences

The current standard protocol, IPV4, has reached its limit in terms of addressing possibilities, being limited by the 32-bits addressing scheme. Its successor, IPV6, had been devised since the mid 1990’s. In addition to handling the address limitations, IPV6 also includes a number of improved features, making it superior to IPV4 in several aspects. However, its deployment has taken much longer than expected. This paper presents how the design IPV6 improved over IPV4, the additional benefits of the newdesign, and challenges faced for the deployment of IPV6. It then outlines the deployment strategies adopted by different countries. It finally discusses how Mauritius can benefit from the IPV6 deployment and what lessons it can draw from deployment experiences obtained elsewhere