MRBench: A Benchmark for MapReduce Framework

MapReduce is Google’s programming model for easy development of scalable parallel applications which pro-cess huge quantity of data on many clusters. Due to its conveniency and efficiency, MapReduce is used in various applications (e.g., web search services and on-line analytical processing.) However, there are only few good benchmarks to evaluate MapReduce implementa-tions by realistic testsets. In this paper, we present MRBench that is a bench-mark for evaluating MapReduce systems. MRBench fo-cuses on processing business oriented queries and con-current data modifications. To this end, we build MR-Bench to deal with large volumes of relational data and execute highly complex queries. By MRBench, users can evaluate the performance of MapReduce systems while varying environmental parameters such as data size and the number of (Map/Reduce) tasks. Our ex-tensive experimental results show that MRBench is a useful tool to benchmark the capability of answering critical business questions.

An Asynchronous Protocol for Release Consistent Distributed Shared Memory Systems

Distributed shared memory (DSM) systems[1] provide a simple programming paradigm for networks of workstations, which are gaining popularity due to their cost-effective high computing power. However, DSM systems usually exhibit poor performance due to the large communication delay between the nodes. A lot of different memory consistency models have been proposed to mask the delay due to network communication. In this paper, we propose an asynchronous protocol for the release consistent memory model, which we call Asynchronous Release Consistency (ARC) protocol. In ARC, the network delay is reduced by proper prefetching of pages and two network interfaces are used to perform the prefetching of pages asynchronously with the other synchronization operations. We have compared the performance of the proposed protocol with the lazy invalidate protocol by running standard benchmark programs and we found that ARC achieves up to 29% performance improvement. 1 Introduction Software distributed ..

Caching Strategies for Continuous-media Servers

Data Caching is widely used to improve the performance of multimedia systems. Even though Several caching schemes have been proposed for multimedia systems, they only try to improve the cache hit ratio. Since the continuous-media servers should guarantee hiccup-free services, a high cache hit ratio alone does not capture the effectiveness of a caching scheme. We first show that the conventional multimedia caching schemes do not guarantee deterministic service and propose several caching schemes providing deterministic, hiccup-free service. Keywords : Quality of Service, Scheduling, Resource Management, Multimedia Database, Buffer Management 1 Introduction In multimedia systems dealing with continuous-media, the most important objective is to provide continuous services to all the clients. In order to ensure continuous delivery of digital video or audio, reservation of various resources(e.g., disk bandwidth, memory, network bandwidth, etc.) is required before starting playback of a s..

A Single Phase Distributed Commit Protocol for Main Memory DatabaseSystems

Distributed database systems need commit processing so that transactions executing on them still preserve the ACID property. With the advance of main memory database systems which become possible due to dropping price and increasing capacity of the RAM and CPU, the database processing speed has been incresed in one order of magnitude. However, when it comes to distributed commit processing, it is still very slow since disk logging has to precede the transaction commit where the database access does not incur any disk access at all in the case of main memory databases. In this paper, we re-evaluate the various distributed commit protocols' and come up with a single phase distributed commit protocol suitable for the distributed main memory database systems. Our simulation study confirms that the new protocol greatly reduces the time it takes to commit distributed transactions without any consistency problem

Statistical Admission Control for Soft Real-Time VOD Servers

To fully utilize the resources with soft real-time video-on-demand servers, statistical admission control is widely used. There have been several models to capture the nature of bit rate variability of the video data. However, when the video server employs caching, the resulting workload exhibits different characteristics. In this paper, we present a probabilistic model to analyze the video server workload. Our model enables the quantitative analysis of the disk load reduction induced by caching so that the caching effect can be reflected in the admission control. Using this model, it is possible to design a statistical admission control which provides a probabilistic guarantee for the jitter free playback

IP Concatenation: The Method for Enhancement of IPsec Performance

IPsec provides security services at the IP layer. The performance of IPsec is markedly decreased when it handles small packets. In this paper, we propose a method, IP packet concatenation (IPConc), to improve throughput of small packet processing. Our proposal reduces the number of packets and overall load for packet processing and IPsec processing. We implemented IPConc with Linux 2.4.17 and FreeS/WAN 1.95. The system which is enhanced by our proposal performed signi - cantly better than original version. The throughput with 64 byte packets was increased as much as 250%