Dynamic routing balancing on InfiniBand network

InfiniBand (IBA) technology was developed to address the performance issues associated with messages movement among Endnodes and computer I/O devices. However, InfiniBand is also widely deployed within high performance computing (HPC) clusters due to the high bandwidth and low message latency attributes it offers to inter-processor communication systems. An interconnection-network efficient design is mandatory because its great impact on the parallel computer performance. Therefore, a high speed routing scheme that minimizes congestion and avoids hot-spot areas should be included in the network components. We have developed Dynamic Routing Balancing (DRB), an adaptive routing mechanism that balances the communication traffic over the interconnection network. It is based on limited and load-controlled multipath expansion in order to maintain low and bounded network latency. In this work, we propose using DRB as the congestion control mechanism for InfiniBand networks. Experimentation shows that our method achieves significant performance improvement over the original InfiniBand technique which is based on message throttling. An improvement up to 66% for latency and 35% for throughput is achieved for the networks under analysis. Finally, the proposed mechanism use the management model defined in InfiniBand specs, thus full compatibility is provided.Facultad de Informátic

Balanceo distribuido del encaminamiento para el control de congestión en redes infiniband

El uso de recursos compartidos en las redes de interconexión de alta performance puede provocar situaciones de congestión de mensajes que degradan notablemente las prestaciones, aumentando la latencia de trasporte y disminuyendo la utilización de la red. Hasta el momento las técnicas que intentan solucionar este problema utilizan la regulación de la inyección de mensajes. Esta limitación de la inyección traslada la contención de mensajes desde los conmutadores hacia los nodos fuente, incrementando el valor de la latencia promedio global, pudiendo alcanzar valores muy elevados. En este artículo, proponemos una técnica de control de congestión para redes InfiniBand basada en un mecanismo de encaminamiento adaptativo que distribuye el volumen de comunicaciones entre diversas trayectorias alternativas quitando carga de la zona de congestión, lo que permite eliminarla. La experimentación realizada muestra la mejora obtenida en latencia y throughput, respecto al mecanismo de control de congestión original de InfiniBand basado en la regulación de la inyección. El mecanismo propuesto es totalmente compatible y no requiere que se modifique ningún aspecto de la especificación, debido a que se utilizan componentes de gestión definidos en el estándar InfiniBand.Communications requirements in High Performance Computing (HPC) demand the use of Interconnections Networks to connect processing nodes. Sharing resources in high performance interconnection networks leads to message congestion. Congestion spreading increases latency and reduces network throughput causing important performance degradation. Nowadays most current techniques use message throttling to prevent injection of new messages in network congested region. Message throttling moves contention from switches to sources nodes in order to eliminate congestion, however global latency is highly incremented because of the time that packets must wait in the source node. In this paper, we propose a congestion control mechanism for InfiniBand networks based in an adaptive routing algorithm that perform a communication load balancing over several alternative paths, in order to take load away of the congested network zone, eliminating congestion and maintaining injection rate. Our mechanism’s experimentation results show latency, throughput and dynamic behaviour improvement over InfiniBand original congestion control mechanism which is based in message throttling. The proposed mechanism use the management model defined in InfiniBand specs, thus full compatibility is provided.VIII Workshop de Procesamiento Distribuido y ParaleloRed de Universidades con Carreras en Informática (RedUNCI

Balanceo distribuido del encaminamiento para el control de congestión en redes infiniband

El uso de recursos compartidos en las redes de interconexión de alta performance puede provocar situaciones de congestión de mensajes que degradan notablemente las prestaciones, aumentando la latencia de trasporte y disminuyendo la utilización de la red. Hasta el momento las técnicas que intentan solucionar este problema utilizan la regulación de la inyección de mensajes. Esta limitación de la inyección traslada la contención de mensajes desde los conmutadores hacia los nodos fuente, incrementando el valor de la latencia promedio global, pudiendo alcanzar valores muy elevados. En este artículo, proponemos una técnica de control de congestión para redes InfiniBand basada en un mecanismo de encaminamiento adaptativo que distribuye el volumen de comunicaciones entre diversas trayectorias alternativas quitando carga de la zona de congestión, lo que permite eliminarla. La experimentación realizada muestra la mejora obtenida en latencia y throughput, respecto al mecanismo de control de congestión original de InfiniBand basado en la regulación de la inyección. El mecanismo propuesto es totalmente compatible y no requiere que se modifique ningún aspecto de la especificación, debido a que se utilizan componentes de gestión definidos en el estándar InfiniBand.Communications requirements in High Performance Computing (HPC) demand the use of Interconnections Networks to connect processing nodes. Sharing resources in high performance interconnection networks leads to message congestion. Congestion spreading increases latency and reduces network throughput causing important performance degradation. Nowadays most current techniques use message throttling to prevent injection of new messages in network congested region. Message throttling moves contention from switches to sources nodes in order to eliminate congestion, however global latency is highly incremented because of the time that packets must wait in the source node. In this paper, we propose a congestion control mechanism for InfiniBand networks based in an adaptive routing algorithm that perform a communication load balancing over several alternative paths, in order to take load away of the congested network zone, eliminating congestion and maintaining injection rate. Our mechanism’s experimentation results show latency, throughput and dynamic behaviour improvement over InfiniBand original congestion control mechanism which is based in message throttling. The proposed mechanism use the management model defined in InfiniBand specs, thus full compatibility is provided.VIII Workshop de Procesamiento Distribuido y ParaleloRed de Universidades con Carreras en Informática (RedUNCI

Hot-Spot Avoidance With Multi-Pathing Over Infiniband: An MPI Perspective

Large scale InfiniBand clusters are becoming increasingly popular, as reflected by the TOP 500 Supercomputer rankings. At the same time, fat tree has become a popular interconnection topology for these clusters, since it allows multiple paths to be available in between a pair of nodes. However, even with fat tree, hot-spots may occur in the network depending upon the route configuration between end nodes and communication pattern(s) in the application. To make matters worse, the deterministic routing nature of InfiniBand limits the application from effective use of multiple paths transparently and avoid the hot-spots in the network. Simulation based studies for switches and adapters to implement congestion control have been proposed in the literature. However, these studies have focused on providing congestion control for the communication path, and not on utilizing multiple paths in the network for hot-spot avoidance. In this paper, we design an MPI functionality, which provides hot-spot avoidance for different communications, without a priori knowledge of the pattern. We leverage LMC (LID Mask Count) mechanism of InfiniBand to create multiple paths in the network and present the design issues (scheduling policies, selecting number of paths, scalability aspects) of our design. We implement our design and evaluate it with Pallas collective communication and MPI applications. On an InfiniBand cluster with 48 processes, collective operations like MPI All-to-all Personalized and MPI Reduce Scatter show an improvement of 27% and 19% respectively. Our evaluation with MPI applications like NAS Parallel Benchmarks and PSTSWM on 64 processes shows significant improvement in execution time with this functionality

Balanceo distribuido del encaminamiento para el control de congestión en redes infiniband

El uso de recursos compartidos en las redes de interconexión de alta performance puede provocar situaciones de congestión de mensajes que degradan notablemente las prestaciones, aumentando la latencia de trasporte y disminuyendo la utilización de la red. Hasta el momento las técnicas que intentan solucionar este problema utilizan la regulación de la inyección de mensajes. Esta limitación de la inyección traslada la contención de mensajes desde los conmutadores hacia los nodos fuente, incrementando el valor de la latencia promedio global, pudiendo alcanzar valores muy elevados. En este artículo, proponemos una técnica de control de congestión para redes InfiniBand basada en un mecanismo de encaminamiento adaptativo que distribuye el volumen de comunicaciones entre diversas trayectorias alternativas quitando carga de la zona de congestión, lo que permite eliminarla. La experimentación realizada muestra la mejora obtenida en latencia y throughput, respecto al mecanismo de control de congestión original de InfiniBand basado en la regulación de la inyección. El mecanismo propuesto es totalmente compatible y no requiere que se modifique ningún aspecto de la especificación, debido a que se utilizan componentes de gestión definidos en el estándar InfiniBand.Communications requirements in High Performance Computing (HPC) demand the use of Interconnections Networks to connect processing nodes. Sharing resources in high performance interconnection networks leads to message congestion. Congestion spreading increases latency and reduces network throughput causing important performance degradation. Nowadays most current techniques use message throttling to prevent injection of new messages in network congested region. Message throttling moves contention from switches to sources nodes in order to eliminate congestion, however global latency is highly incremented because of the time that packets must wait in the source node. In this paper, we propose a congestion control mechanism for InfiniBand networks based in an adaptive routing algorithm that perform a communication load balancing over several alternative paths, in order to take load away of the congested network zone, eliminating congestion and maintaining injection rate. Our mechanism’s experimentation results show latency, throughput and dynamic behaviour improvement over InfiniBand original congestion control mechanism which is based in message throttling. The proposed mechanism use the management model defined in InfiniBand specs, thus full compatibility is provided.VIII Workshop de Procesamiento Distribuido y ParaleloRed de Universidades con Carreras en Informática (RedUNCI

Progressive congestion management based on packet marking and validation techniques

© 2012 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.Congestion management in multistage interconnection networks is a serious problem, which is not solved completely. In order to avoid the degradation of network performance when congestion appears, several congestion management mechanisms have been proposed. Most of these mechanisms are based on explicit congestion notification. For this purpose, switches detect congestion and depending on the applied strategy, packets are marked to warn the source hosts. In response, source hosts apply some corrective actions to adjust their packet injection rate. Although these proposals seem quite effective, they either exhibit some drawbacks or are partial solutions. Some of them introduce some penalties over the flows not responsible for congestion, whereas others can cope only with congestion situations that last for a short time. In this paper, we present an overview of the different strategies to detect and correct congestion in multistage interconnection networks, and propose a new mechanism referred to as Marking and Validation Congestion Management (MVCM), targeted to this kind of lossless networks, and based on a more refined packet marking strategy combined with a fair set of corrective actions, that makes the mechanism able to effectively manage congestion regardless of the congestion degree. Evaluation results show the effectiveness and robustness of the proposed mechanism.This work was supported by the Spanish MEC and MICINN, as well as European Commission FEDER funds, under Grants CSD2006-00046 and TIN2009-14475-C04-01.Ferrer Pérez, JL.; Baydal Cardona, ME.; Robles Martínez, A.; López Rodríguez, PJ.; Duato Marín, JF. (2012). Progressive congestion management based on packet marking and validation techniques. IEEE Transactions on Computers. 61(9):1296-1309. doi:10.1109/TC.2011.146S1296130961

Performance analysis and improvement of InfiniBand networks. Modelling and effective Quality-of-Service mechanisms for interconnection networks in cluster computing systems.

The InfiniBand Architecture (IBA) network has been proposed as a new industrial standard with high-bandwidth and low-latency suitable for constructing high-performance interconnected cluster computing systems. This architecture replaces the traditional bus-based interconnection with a switch-based network for the server Input-Output (I/O) and inter-processor communications. The efficient Quality-of-Service (QoS) mechanism is fundamental to ensure the import at QoS metrics, such as maximum throughput and minimum latency, leaving aside other aspects like guarantee to reduce the delay, blocking probability, and mean queue length, etc. Performance modelling and analysis has been and continues to be of great theoretical and practical importance in the design and development of communication networks. This thesis aims to investigate efficient and cost-effective QoS mechanisms for performance analysis and improvement of InfiniBand networks in cluster-based computing systems. Firstly, a rate-based source-response link-by-link admission and congestion control function with improved Explicit Congestion Notification (ECN) packet marking scheme is developed. This function adopts the rate control to reduce congestion of multiple-class traffic. Secondly, a credit-based flow control scheme is presented to reduce the mean queue length, throughput and response time of the system. In order to evaluate the performance of this scheme, a new queueing network model is developed. Theoretical analysis and simulation experiments show that these two schemes are quite effective and suitable for InfiniBand networks. Finally, to obtain a thorough and deep understanding of the performance attributes of InfiniBand Architecture network, two efficient threshold function flow control mechanisms are proposed to enhance the QoS of InfiniBand networks; one is Entry Threshold that sets the threshold for each entry in the arbitration table, and other is Arrival Job Threshold that sets the threshold based on the number of jobs in each Virtual Lane. Furthermore, the principle of Maximum Entropy is adopted to analyse these two new mechanisms with the Generalized Exponential (GE)-Type distribution for modelling the inter-arrival times and service times of the input traffic. Extensive simulation experiments are conducted to validate the accuracy of the analytical models

End-to-end congestion control for InfiniBand

Abstract — InfiniBand System Area Networks (SANs) which use link-level flow control experience congestion spreading, where one bottleneck link causes traffic to block throughout the network. In this paper, we propose an end-to-end congestion control scheme that avoids congestion spreading, delivers high throughput, and prevents flow starvation. It couples a simple switch-based ECN packet marking mechanism appropriate for typical SAN switches with small input buffers, together with a source response mechanism that uses rate control combined with a window limit. The classic fairness convergence requirement for source response functions assumes network feedback is synchronous. We relax the classic requirement by exploiting the asynchronous behavior of packet marking. Our experimental results demonstrate that compared to conventional approaches, our proposed marking mechanism improves fairness. Moreover, rate increase functions possible under the relaxed requirement reclaim available bandwidth aggressively and improve throughput in both static and dynamic traffic scenarios. I

End-to-end congestion control for InfiniBand

congestion control, rate control, system area networks, SAN, InfiniBand InfiniBand System Area Networks (SANs) which use link-level flow control experience congestion spreading, where one bottleneck link causes traffic to block throughout the network. In this paper, we propose an end-to-end congestion control scheme that avoids congestion spreading, delivers high throughput, and prevents flow starvation. It couples a simple switch-based ECN packet marking mechanism appropriate for typical SAN switches with small input buffers, together with a source response mechanism that uses rate control combined with a window limit. The classic fairness convergence requirement for source response functions assumes network feedback is synchronous. We relax the classic requirement by exploiting the asynchronous behavior of packet marking. Our experimental results demonstrate that compared to conventional approaches, our proposed marking mechanism improves fairness. Moreover, rate increase functions possible under the relaxed requirement reclaim available bandwidth aggressively and improve throughput in both static and dynamic traffic scenarios

Anales del XIII Congreso Argentino de Ciencias de la Computación (CACIC)

Contenido: Arquitecturas de computadoras Sistemas embebidos Arquitecturas orientadas a servicios (SOA) Redes de comunicaciones Redes heterogéneas Redes de Avanzada Redes inalámbricas Redes móviles Redes activas Administración y monitoreo de redes y servicios Calidad de Servicio (QoS, SLAs) Seguridad informática y autenticación, privacidad Infraestructura para firma digital y certificados digitales Análisis y detección de vulnerabilidades Sistemas operativos Sistemas P2P Middleware Infraestructura para grid Servicios de integración (Web Services o .Net)Red de Universidades con Carreras en Informática (RedUNCI