Improving the benefits of multicast prioritization algorithms

The final publication is available at Springer via http://dx.doi.org/10.1007/s11227-014-1087-zPrioritized atomic multicast consists in delivering messages in total order while ensuring that the priorities of the messages are considered; i.e., messages with higher priorities are delivered first. That service can be used in multiple applications. An example is the usage of prioritization algorithms for reducing the transaction abort rates in applications that use a replicated database system. To this end, transaction messages get priorities according to their probability of violating the existing integrity constraints. This paper evaluates how that abort reduction may be improved varying the message sending rate and the bounds set on the length of the priority reordering queue being used by those multicast algorithms.This work has been partially supported by EU FEDER and Spanish MICINN under research Grants TIN2009-14460-C03-01 and TIN2010-17193.Miedes De Elías, EP.; Muñoz Escoí, FD. (2014). Improving the benefits of multicast prioritization algorithms. Journal of Supercomputing. 68(3):1280-1301. doi:10.1007/s11227-014-1087-zS12801301683Amir Y, Danilov C, Stanton JR (2000) A low latency, loss tolerant architecture and protocol for wide area group communication. In: International Conference on Dependable Systems and Networks (DSN), IEEE-CS, Washington, DC, USA, pp 327–336Chockler G, Keidar I, Vitenberg R (2001) Group communication specifications: a comprehensive study. ACM Comput Surv 33(4):427–469CiA (2001) About CAN in Automation (CiA). http://www.can-cia.org/index.php?id=aboutciaDéfago X, Schiper A, Urbán P (2004) Total order broadcast and multicast algorithms: taxonomy and survey. ACM Comput Surv 36(4):372–421Dolev D, Dwork C, Stockmeyer L (1987) On the minimal synchronism needed for distributed consensus. J ACM 34(1):77–97International Organization for Standardization (ISO) (1993) Road vehicles—interchange of digital information—controller area network (CAN) for high-speed communication. Revised by ISO 11898-1:2003JBoss (2011) The Netty project 3.2 user guide. http://docs.jboss.org/netty/3.2/guide/html/Kaashoek MF, Tanenbaum AS (1996) An evaluation of the Amoeba group communication system. In: International conference on distributed computing system (ICDCS), IEEE-CS, Washington, DC, USA, pp 436–448Miedes E, Muñoz-Escoí FD (2008) Managing priorities in atomic multicast protocols. In: International conference on availability, reliability and security (ARES), Barcelona, Spain, pp 514–519Miedes E, Muñoz-Escoí FD (2010) Dynamic switching of total-order broadcast protocols. In: International conference on parallel and distributed processing techniques and applications (PDPTA), CSREA Press, Las Vegas, Nevada, USA, pp 457–463Miedes E, Muñoz-Escoí FD, Decker H (2008) Reducing transaction abort rates with prioritized atomic multicast protocols. In: International European conference on parallel and distributed computing (Euro-Par), Springer, Las Palmas de Gran Canaria, Spain, Lecture notes in computer science, vol 5168, pp 394–403Mocito J, Rodrigues L (2006) Run-time switching between total order algorithms. In: International European conference on parallel and distributed computing (Euro-Par), Springer, Dresden, Germany, Lecture Notes in Computer Science, vol 4128, pp 582–591Moser LE, Melliar-Smith PM, Agarwal DA, Budhia R, Lingley-Papadopoulos C (1996) Totem: a fault-tolerant multicast group communication system. Commun ACM 39(4):54–63Nakamura A, Takizawa M (1992) Priority-based total and semi-total ordering broadcast protocols. In: International conference on distributed computing systems (ICDCS), Yokohama, Japan, pp 178–185Nakamura A, Takizawa M (1993) Starvation-prevented priority based total ordering broadcast protocol on high-speed single channel network. In: 2nd International symposium on high performance distributed computing (HPDC), pp 281–288Rodrigues L, Veríssimo P, Casimiro A (1995) Priority-based totally ordered multicast. In: Workshop on algorithms and architectures for real-time control (AARTC), Ostend, BelgiumRütti O, Wojciechowski P, Schiper A (2006) Structural and algorithmic issues of dynamic protocol update. In: 20th International parallel and distributed processing symposium (IPDPS), IEEE-CS Press, Rhodes Island, GreeceTindell K, Clark J (1994) Holistic schedulability analysis for distributed hard real-time systems. Microprocess Microprogr 40(2–3):117–134Tully A, Shrivastava SK (1990) Preventing state divergence in replicated distributed programs. In: International symposium on reliable distributed systems (SRDS), Huntsville, Alabama, USA, pp 104–113Wiesmann M, Schiper A (2005) Comparison of database replication techniques based on total order broadcast. IEEE Trans Knowl Data Eng 17(4):551–56

Performance and Power Analysis of HPC Workloads on Heterogenous Multi-Node Clusters

Performance analysis tools allow application developers to identify and characterize the inefficiencies that cause performance degradation in their codes, allowing for application optimizations. Due to the increasing interest in the High Performance Computing (HPC) community towards energy-efficiency issues, it is of paramount importance to be able to correlate performance and power figures within the same profiling and analysis tools. For this reason, we present a performance and energy-efficiency study aimed at demonstrating how a single tool can be used to collect most of the relevant metrics. In particular, we show how the same analysis techniques can be applicable on different architectures, analyzing the same HPC application on a high-end and a low-power cluster. The former cluster embeds Intel Haswell CPUs and NVIDIA K80 GPUs, while the latter is made up of NVIDIA Jetson TX1 boards, each hosting an Arm Cortex-A57 CPU and an NVIDIA Tegra X1 Maxwell GPU.The research leading to these results has received funding from the European Community’s Seventh Framework Programme [FP7/2007-2013] and Horizon 2020 under the Mont-Blanc projects [17], grant agreements n. 288777, 610402 and 671697. E.C. was partially founded by “Contributo 5 per mille assegnato all’Università degli Studi di Ferrara-dichiarazione dei redditi dell’anno 2014”. We thank the University of Ferrara and INFN Ferrara for the access to the COKA Cluster. We warmly thank the BSC tools group, supporting us for the smooth integration and test of our setup within Extrae and Paraver.Peer ReviewedPostprint (published version

Load-Sharing Policies in Parallel Simulation of Agent-Based Demographic Models

Execution parallelism in agent-Based Simulation (ABS) allows to deal with complex/large-scale models. This raises the need for runtime environments able to fully exploit hardware parallelism, while jointly offering ABS-suited programming abstractions. In this paper, we target last-generation Parallel Discrete Event Simulation (PDES) platforms for multicore systems. We discuss a programming model to support both implicit (in-place access) and explicit (message passing) interactions across concurrent Logical Processes (LPs). We discuss different load-sharing policies combining event rate and implicit/explicit LPs’ interactions. We present a performance study conducted on a synthetic test case, representative of a class of agent-based models

Multi-Node Advanced Performance and Power Analysis with Paraver

Performance analysis tools allow application developers to identify and characterize the inefficiencies that cause performance degradation in their codes. Due to the increasing interest in the High Performance Computing (HPC) community towards energy-efficiency issues, it is of paramount importance to be able to correlate performance and power figures within the same profiling and analysis tools. For this reason, we present a preliminary performance and energy-efficiency study aimed at demonstrating how a single tool can be used to collect most of the relevant metrics. Moreover we show how the same analysis techniques are applicable on different architectures, analyzing the same HPC application running on two clusters, based respectively on Intel Haswell and Arm Cortex-A57 CPUs.The research leading to these results has received funding from the European Community’s Seventh Framework Programme [FP7/2007-2013] and Horizon 2020 under the Mont-Blanc projects, grant agreements n. 288777, 610402 and 671697. E.C. was partially founded by “Contributo 5 per mille assegnato all’Universit`a degli Studi di Ferrara - dichiarazione dei redditi dell’anno 2014”.Peer ReviewedPostprint (author's final draft

Neural Machine Translation into Language Varieties

Both research and commercial machine translation have so far neglected the importance of properly handling the spelling, lexical and grammar divergences occurring among language varieties. Notable cases are standard national varieties such as Brazilian and European Portuguese, and Canadian and European French, which popular online machine translation services are not keeping distinct. We show that an evident side effect of modeling such varieties as unique classes is the generation of inconsistent translations. In this work, we investigate the problem of training neural machine translation from English to specific pairs of language varieties, assuming both labeled and unlabeled parallel texts, and low-resource conditions. We report experiments from English to two pairs of dialects, EuropeanBrazilian Portuguese and European-Canadian French, and two pairs of standardized varieties, Croatian-Serbian and Indonesian-Malay. We show significant BLEU score improvements over baseline systems when translation into similar languages is learned as a multilingual task with shared representations.Comment: Published at EMNLP 2018: third conference on machine translation (WMT 2018

Recent Advances in Graph Partitioning

We survey recent trends in practical algorithms for balanced graph partitioning together with applications and future research directions