Degree of parallelism

About: Degree of parallelism is a research topic. Over the lifetime, 1515 publications have been published within this topic receiving 25546 citations.

Bus coupled systems for multigrid algorithms

Abstract: Speedup and efficiency of some simple parallel multigrid algorithms for a class of bus coupled systems are investigated. We consider some basic multigrid methods (V-cycle, W-cycle) with regular grid generation and without local refinements. Our bus coupled systems consist of many independent processors each with its own local memory. A typical example for our abstract bus concept is a ring bus. The investigation of such systems is restricted to hierarchical orthogonal systems. Simple orthogonal bus systems, tree structures and mixed types are included in our general model. It can be shown that all systems are of identical suitability if the tasks are sufficiently large. The smaller however the degree of parallelism of an algorithm is, the clearer are the differences in the performance of the various systems. We can classify the most powerful systems and systems with lower performance but better technical properties. Complexity investigations enabled us to evaluate the different systems. These investigations are complemented by simulations based on the different parallel algorithms.

AMR++: A Design for Parallel Object-Oriented Adaptive Mesh Refinement

Abstract: Adaptive mesh refinement computations are complicated by their dynamic nature In the serial environment they require substantial infrastructures to support the regridding processes, intergrid operations, and local bookkeeping of positions of grids relative to one another In the parallel environment the dynamic behavior is more problematic because it requires dynamic distribution support and load balancing Parallel AMR is further complicated by the substantial task parallelism, in addition to the obvious data parallelism, this task parallelism requires additional infrastructure to support efficiently [6] The degree of parallelism is typically dependent upon the algorithms in use and the equations being solved Different algorithms have significant compromises between computation and communication Substantial research work is often required to define efficient methods and suitable infrastructure The purpose of this paper is to introduce AMR++ as an object-oriented library which forms a part of the OVERTURE framework, a much larger object-oriented numerical framework developed and supported at Los Alamos National Laboratory and distributed on the Web for the last several years

Packet capturing on parallel architectures

Abstract: Nowadays commodity hardware is offering an ever increasing degree of parallelism: CPUs are equipped with more and more cores and a new generation of NICs can dispatch packets across multiple queues Software based network monitoring can leverage the opportunity offered by this new trend in order to target a level of performance which was unattainable with single core technologies In this paper, which is the result of a thorough measurement campaign, we explore the potential of parallelism when coupled with existing packet capturing technologies and show how, by accurately tuning configurations, a huge performance gain can be obtained We also show how minimal configuration changes can dramatically affect the overall throughput

CONTRAST: Container-based Transcoding for Interactive Video Streaming

Abstract: Interactive video streaming applications are becoming increasingly popular. To maintain the Quality of Experience (QoE) of an end user, interactive streaming platforms need to transcode a video stream, i.e., adapt the quality of the video content, to match the network conditions between the platform and the user as well as the device capabilities of the end user. Modern video codecs such as High Efficiency Video Coding (HEVC) require significant computational resources for transcoding operations. Consequently, there is a need for systems that can perform transcoding quickly at runtime to sustain the real-time performance required for interactive streaming while at the same time using just the right amount of computational resources for the transcoding operations. This paper addresses this need by designing and implementing CONTRAST, a Container- based Distributed Transcoding Framework for Interactive Video Streaming. For any given stream and transcoding resolution, CONTRAST exploits a profiling technique to automatically determine the degree of parallelism, Le., the number of processing cores, demanded by the transcoding process to sustain the stream’s frame rate. It then launches Docker containers configured with the required number of cores to perform the transcoding. Experiments using a set of realistic video streams show that CONTRAST is able to sustain the frame rate requirements for interactive streams in a more resource efficient manner compared to baseline techniques that do not consider the degree of parallelism. To the best of our knowledge, our paper is the first to establish best practices for implementing transcoding platforms for interactive streaming videos encoded using a modem video codec.

Parallel and survivable multipath circuit provisioning in ESnet's OSCARS

Abstract: Data generation is approaching petascale and exascale rates by cutting-edge science and research applications varying from material informatics to physics. With data generation and management comes the necessity to transmit such vast collections of information across the world's networks for processing, analysis, storage, or peer-sharing. This practice is becoming the norm to the large-scale scientific community, but complications can arise during networking. There are countless situations such as component failure due to a harmless construction accident or a devastating natural disaster that may lead to catastrophic interruption of service. Furthermore, given the size of datasets, there is a strong need to support intelligent and fast parallelism throughout the network to allow end users to efficiently consume available bandwidth. We therefore propose a multipath extension for ESnet's On-demand Secure Circuits and Advance Reservation System (OSCARS), the network research community's most popular long-lived circuit-provisioning software package. Presently, OSCARS supports purely point-to-point circuits; however, our proposed client software provides an overlay onto the default OSCARS path computation engine that enables end users to route their data along multiple link-disjoint paths to provide session survivability and increase the degree of parallelism. We have also adapted the proposed multipath extension to an existing anycast OSCARS deployment, which allows for the selection of one preferred destination node from among a set of potential candidates. Through thorough simulation analysis and exposure to realistic failure event distributions, we quantitatively evaluate the multipath client performance and showcase the relative benefits when compared to the standard single-path OSCARS deployment.