Task-based programming models for shared memory—such as Cilk Plus and OpenMP 3—are well established and documented. However, with the increase in parallel, many-core, and heterogeneous systems, a number of research-driven projects have developed more diversified task-based support, employing various programming and runtime features. Unfortunately, despite the fact that dozens of different task-based systems exist today and are actively used for parallel and high-performance computing (HPC), no comprehensive overview or classification of task-based technologies for HPC exists. In this paper, we provide an initial task-focused taxonomy for HPC technologies, which covers both programming interfaces and runtime mechanisms. We demonstrate the usefulness of our taxonomy by classifying state-of-the-art task-based environments in use today.

This paper presents a media- and TCP-friendly rate-based congestion control algorithm (MTFRCC) for scalable video streaming in the Internet. The algorithm integrates two new techniques: i) a utility-based model using the rate-distortion function as the application utility measure for optimizing the overall video quality; and ii) a two-timescale approach of rate averages (long-term and short-term) to satisfy both media and TCP-friendliness. We evaluate our algorithm through simulation and compare the results against the TCP-friendly rate control (TFRC) algorithm. For assessment, we consider five criteria: TCP fairness, responsiveness, aggressiveness, overall video quality, and smoothness of the resulting bit rate. Our simulation results manifest that MTFRCC performs better than TFRC for various congestion levels, including an improvement of the overall video quality.

In response to the need for higher-speed and affordable-cost datacenter interconnection networks, hybrid optical/electrical architectures have been proposed. Even still, a number of implementation issues remain open and little is known about the performance of real applications over such networks. To fill this gap, we present a hybrid network architecture, called HydRA, comprising commodity off-the-shelf equipment, calculate its total price using current list prices, and show its price competitiveness against fat-tree alternatives. We also report on a prototype implementation of our HydRA network that uses Ethernet switches and a custom-built software controller. We show that our HydRA network prototype manages to accelerate the execution of real parallel workloads, when compared to equal-cost electronic-only fat-tree networks.

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