Yonghao Wang

An efficient task mapping algorithm with power-aware optimization for network on chip

An online scheduling is proposed for NOC-based manycore systems.The task with heavy traffic is mapped to the core first.The tasks are re-mapped according to the run-time information.Communication-intensive scheduling gathers the tasks in different regions.A large portion of the communication latency and power consumption is reduced. More and more cores are integrated onto a single chip to improve the performance and reduce the power consumption of CPU without the increased frequency. The cores are connected by lines and organized as a network, which is called network on chip (NOC) as the promising paradigm of the processor design. However, it is still a challenge to enhance performance with lower power consumption. The core issue is how to map the tasks to the different cores to take full advantages of the on-chip network. In this paper, we proposed a novel mapping algorithm with power-aware optimization for NOC. The traffic of the tasks will be analyzed. The tasks of the same application with high communication with the others will be mapped to the on-chip network as neighborhoods. And then the tasks of different applications are mapped to the cores step by step. The mapping of the tasks and the cores is computed at run-time dynamically and implement online. The experimental results showed that this proposed algorithm can reduce the power consumption in communication and the performance enhanced.

A Hybrid Algorithm Based on Particle Swarm Optimization and Ant Colony Optimization Algorithm

Particle swarm optimization (PSO) and Ant Colony Optimization (ACO) are two important methods of stochastic global optimization. PSO has fast global search capability with fast initial speed. But when it is close to the optimal solution, its convergence speed is slow and easy to fall into the local optimal solution. ACO can converge to the optimal path through the accumulation and update of the information with the distributed parallel global search ability. But it has slow solving speed for the lack of initial pheromone at the beginning. In this paper, the hybrid algorithm is proposed in order to use the advantages of both of the two algorithm. PSO is first used to search the global solution. When it maybe fall in local one, ACO is used to complete the search for the optimal solution according to the specific conditions. The experimental results show that the hybrid algorithm has achieved the design target with fast and accurate search.

Evaluation of video payload over low latency networks: Flexilink

ABSTRACT Broadcast organisations need to handle both time deterministic traffic and best effort traffic. The adoption of packet networks allows a single converged network for handling both real-time (RT) media traffic as well as data traffic. Due to the historic pervasive growth of IP network, they are widely used to realise this converged network. However, they do have several drawbacks like big header size, software switching delays and inability to support multiple addressing schemes. To overcome these issues, solutions like traffic engineering, quality of service and over-provisioning are implemented in IP networks but has resulted in higher cost, power and system requirements. Flexilink network has been tested for audio payloads using simulation model and outperforms any existing RT network by providing an exceptional average end-to-end delay of microsecond range and a jitter below the audible threshold for live digital audio streaming. However, it is not tested for video payloads. A review of various networks used RT media distribution is included in this paper. The Flexilink architecture design modification to support the most widely used video formats such as MPEG-TS, MPEG-PS and SDI streams is explained. The average delay for multiple video streams over Flexilink is provided using simulation model. The recommendation for testing Flexilink using hardware is also explained in this paper. The Flexilink Mac design uses dual-buffer system to handle AF (asynchronous flow) and SF (synchronous flow) separately, with the Frame structure that supports current Ethernet frames. GRAPHICAL ABSTRACT

Constraint-aware software-defined network for routing real-time multimedia

Traditional Ethernet-based IP networks do not have the capability to provide the Quality of Service (QoS) required for professional real-time multimedia applications. This is because they operate on a best-effort network service model that does not provide service guarantee. Network operators and service providers require a novel network architecture to efficiently handle the increasing demands of this changing network domain. Software-Defined Networking has emerged as an effective network architecture that decouples the control plane and data plane, which makes it capable of handling the dynamic nature of future network functions and intelligent applications while reducing cost through simplified hardware, software, and management. This paper presents an SDN architecture for real-time low latency applications that offer adaptive path provisioning based on the calculated end-to-end delay, available bandwidth, and traditional shortest path first algorithm. The SDN architecture utilises the Ryu OpenFlow application programming interface (API) to perform real-time monitoring to collect network statistics and computes the appropriate paths by using this information. The experiment to ascertain the feasibility and evaluate the effectiveness of this approach is carried out in an emulated network environment using Mininet.

Performance Evaluation of a New Flexible Time Division Multiplexing Protocol on Mixed Traffic Types

The broadcasting industry has recently begun to adopt statistical multiplexing based network platform in their workflow to support professional live audio/video (AV) transmission instead of the Time Division Multiplexing (TDM) based system. These audio-over-packet switched systems require a carefully designed and managed network to ensure key quality measures of the real-time (RT) media, such as low jitter and low latency. Often the best effort traffic or different types of media are still physically or logically segregated from these dedicated systems, or require large redundant links. The proposed Flexilink architecture is an alternative that combines both circuit switched and best effort features. However, there is no research evaluation that shows the actual performance of this proposed architecture. In this paper, we give a simulation based study and critical evaluation of the performance of the Flexilink network. The simulation results show that Flexilink has a better and more stable RT performance when compared with both Ethernet and priority queueing networks, especially when given a burst of traffic and/or multiple RT traffic sources. In addition, Unlike other networking protocols, jitter in Flexilink is below the audible threshold.

Practical considerations on optimising multistage decimation and interpolation processes

Multistage filter design is a complex multidimensional optimisation problem. The formulae for optimal design generally yield non-integer real numbers for the sample-rate-changing factors of multiple stages. Approaches yielding useful integer results have high computational cost and do not consider important multistage filter design properties. We have developed a simplified algorithm for directly searching the optimal integer results. Considering the most useful practical design parameters, optimal results can be approximated with a limited number of sets for any designs satisfying certain constraints, with negligible costs. This vastly simplifies the complexity of the problem.

A Novel PSO Based Task Scheduling Algorithm for Multi-core Systems

Multi-core processors have been the mainstream in computer architecture. It also provides the enhancement of the parallelism degree of multiple tasks. An emerged challenge is how to schedule the multiple tasks to the cores for high efficiency. In this paper, a novel task scheduling algorithm is proposed for multi-core systems. This algorithm is based on optimized particle swarm algorithm, which is used to find the optimal solution for the task scheduling. The experimental results have showed that the proposed algorithm can improve the efficiency of task scheduling for multi-core systems.