MPI-Mitten: Enabling Migration Technology in MPI

The paper investigates the use of group communication to improve the efficiency of load balancing in interconnected LANs. Conventional load balancing techniques usually assume point-to-point connections among the computers and typically work on a single LAN only. This may waste network bandwidth and lengthen the load balancing time in LANs that support group communication such as the Ethernet. To tackle this problem a two level algorithm is proposed. At the LAN level, all computers in a LAN maintain loading information in the entire LAN using a globally ordered group channel. The workload in the different LANs is balanced by moving load from the overloaded LANs to the underloaded ones. It is proved that the proposed algorithm converges to the state of global balance geometrically. Experimental results show that the algorithm reduces load balancing time and network utilization significantly, compared to the single level algorithm without group communication.

Process migration protocols for massively parallel systems

The so-called media convergence to the Internet is foreseen. As a consequence of this convergence, MANs will face new demands not only in terms of bandwidth, but also in terms of services. To meet these new demands, new MAN architectures are required. WDM-based MAN architectures that tackle the first problem are available not only in the literature, but also on the market. In this paper we deal with the second problem. Specifically, we describe a novel WDM-based MAN architecture that supports group communication, a service that is expected to increase considerably as new applications converge to the Internet. Based on packet switching, the architecture supports both point-to-point and point-to-multipoint communication in the optical domain.

A novel service-oriented intelligent seamless migration algorithm and application for pervasive computing environments

Process migration is the ability to transfer a process from one machine to another. It is a useful facility in distributed computing environments, especially as computing devices become more pervasive and Internet access becomes more ubiquitous. The potential benefits of process migration, among others, are fault resilience by migrating processes off of faulty hosts, data access locality by migrating processes closer to the data, better system response time by migrating processes closer to users, dynamic load balancing by migrating processes to less loaded hosts, and improved service availability and administration by migrating processes before host maintenance so that applications can continue to run with minimal downtime. Although process migration provides substantial potential benefits and many approaches have been considered, achieving transparent process migration functionality has been difficult in practice. To address this problem, our work has designed, implemented, and evaluated new and powerful transparent process checkpoint-restart and migration mechanisms for desktop, server, and parallel applications that operate across heterogeneous cluster and mobile computing environments. A key aspect of this work has been to introduce lightweight operating system virtualization to provide processes with private, virtual namespaces that decouple and isolate processes from dependencies on the host operating system instance. This decoupling enables processes to be transparently checkpointed and migrated without modifying, recompiling, or relinking applications or the operating system. Building on this lightweight operating system virtualization approach, we have developed novel technologies that enable (1) coordinated, consistent checkpoint-restart and migration of multiple processes, (2) fast checkpointing of process and file system state to enable restart of multiple parallel execution environments and time travel, (3) process migration across heterogeneous software environments, (4) network checkpoint-restart and migration of distributed and parallel applications, (5) a utility computing infrastructure for mobile desktop cloud computing based on process checkpoint-restart and migration functionality, (6) a process migration security architecture for protecting applications and infrastructure from denial-of-service attacks, and (7) a checkpoint-restart mobile computing system using portable storage devices.

Process migration is used in multicore operating systems to improve their performance. The implementation of the migration event contributes largely to the performance of the scheduling algorithm and hence decides how effective a multicore kernel is. There have been several effective algorithms which decide how a process can be migrated from one core to another in a multicore operating system. This paper looks further into the mechanism of process migration in multicore operating systems. The main aim of this paper is not to answer how the process migration should take place but it aims to answer when process migration should take place and to decide the site of process migration. For this, an artificial intelligence concept called genetic algorithm is used. Genetic algorithm works on the theory of survival of the fittest to find an optimally good solution during decision making phase.

Mobile radio group communications enable a closed group of users to communicate among themselves using push-to-talk (PTT), half duplex transmissions, such that one's transmission is received by all. New protocol designs are presented which support group communications over mobile satellite systems. A new demand assignment multiple access (DAMA) protocol is necessitated by the inappropriateness of call-based channel assignments. Channels are assigned to individual user-groups engaged in active conversations. As members of a user-group contend for access to the assigned channel, access control by the usual manual methods is ineffective due to the very long round trip delay. A novel signaling protocol which automates access control is proposed. Carrier sensing, signal capture, and collision detection are employed to minimize access contentions. The throughput and holding time of the assigned channel are analyzed. Numerical results show that the access control protocol improves the capacity of the assigned channel by up to 65%. >

Current group communication services have mostly been implemented on a homogeneous, distributed computing environment. This limits their applicability because most modern distributed computing environment are heterogeneous in nature. This paper describes the design, implementation, and performance evaluation of a CORBA group communication service. Using CORBA to implement a group communication service enables that group communication service to operate in a heterogeneous, distributed computing environment. To evaluate the effect of CORBA on the performance of a group communication service, this paper provides a detailed comparison of the performance measured from three implementations of an atomic broadcast protocol and a group membership protocol. Two of these implementations use CORBA, while the third uses UDP sockets for interprocess communication. The main conclusion is that heterogeneity can be achieved in group communication services by implementing them using CORBA, but there is a substantial performance cost. This performance cost can be reduced to a certain extent by carefully choosing a design and tuning various protocol parameters such as buffer sizes and timer values.

This community service activity is motivated by the local potential of Darungan Hamlet in utilizing herbal plants as health drinks, but is still limited in the aspects of processing, packaging, and marketing. This condition results in low product added value and limited economic opportunities for the community, especially members of the Catleya 3 Dasawisma Group. Motivating the mothers of the Catleya 3 Dasawisma members to become productive individuals will be an opportunity to improve and enhance the quality of family life economically. One effort that can be done is by providing scientific provisions that they can apply by creating something that has economic value. One of these is by making a health drink by utilizing natural resources that can grow well and are abundantly available in Jember. The goal of this activity is to increase the knowledge, skills, and economic independence of the community through innovative herbal dip products and the use of digital technology in marketing. The methods used include socialization, pre-tests and post-tests, training in making herbal dip with three flavors, application of production and packaging technology, and training in creating e-commerce-based marketing accounts. The target of the activity was members of the Catleya 3 Dasawisma Group located in the RT 04/RW 08 area of ​​Darungan Hamlet with a total of 20 participants. The increase in participants' understanding of the use of herbal medicines increased as seen from the average post-test score (80.53±15.80) which was higher than the pre-test score (59.47±13.93). Participants were able to produce herbal dip hygienically and of good quality, package products with attractive labels, and have knowledge related to product marketing through Shopee and Tokopedia. In addition, participants demonstrated independence in managing small businesses based on local potential with the support of production facilities and group communication. This activity succeeded in increasing community knowledge regarding the benefits of traditional medicinal ingredients and how to utilize them, entrepreneurial skills, and expanding participants' knowledge to create e-commerce accounts. Thus, the purpose of community service was achieved, namely the realization of increasing community skills in producing herbal dip sustainably.

The Sprite operating system allows executing processes to be moved between hosts at any time. We use this process migration mechanism to offload work onto idle machines, and also to evict migrated processes when idle workstations are reclaimed by their owners. Sprite's migration mechanism provides a high degree of transparency both for migrated processes and for users. Idle machines are identified, and eviction is invoked, automatically by daemon processes. On Sprite it takes up to a few hundred milliseconds on SPARCstation 1 workstations to perform a remote exec, whereas evictions typically occur in a few seconds. The pmake program uses remote invocation to invoke tasks concurrently. Compilations commonly obtain speed‐up factors in the range of three to six; they are limited primarily by contention for centralized resources such as file servers. CPU‐bound tasks such as simulations can make more effective use of idle hosts, obtaining as much as eight‐fold speed‐up over a period of hours. Process migration has been in regular service for over two years.

Object replication is a technique to enhance fault tolerance and high availability. Group communication is a useful mechanism guaranteeing the consistency among replicated objects. We propose a generic group communication framework that allows transparent plug-in of various group communication protocols with no modification of existing CORBA. For this, we extend the Open Communications Interface (OCI) to support interoperability, reusability of existing group communication, and independency on ORB and OS. The proposed scheme is composed of group membership, group IOR, and group multicast. Experimental results show that group object invocation using the proposed scheme performs substantially better than group object invocations using IIOP as the number of members in a group increases.

OMG has published an unreliable multicast specification for distributed applications developed in CORBA (UMIOP). This mechanism can be implemented based on IP Multicast, a best-effort protocol, which provides no guarantees about the message delivery. However, many fault-tolerant or groupware applications demand more restrictive agreement and ordering guarantees (for instance, reliable multicast with FIFO, causal or total ordering) from the available support for group communication. OMG has not yet provided any specification for supporting those requirements. This paper presents an important contribution towards this direction. We proposed the ReMIOP, an extension to the UMIOP/OMG protocol, for the conception of a reliable multicast mechanism in CORBA middleware. Performance measures comparing ReMIOP, UMIOP and UDP sockets for IP multicast communication are presented in order to evidence the costs for adding reliable and unreliable multicast in middleware level.

The explosive growth of the Internet demands higher reliability and performance than what the current networking infrastructure can provide. This dissertation explores novel architectures and protocols that provide a methodology for grouping together multiple networking elements, such as routers, gateways, and switches, to create a more reliable and performant distributed networking system. Clustering of networking elements is a novel concept that requires the invention of distributed computing protocols that facilitate efficient and robust support of networking protocols. We introduce the Raincore protocol architecture that achieves these goals by bridging the fields of computer networks and distributed systems. In designing Raincore, we paid special attention to the unique requirements from the networking environment. First, networking clusters need to scale up the networking throughput in addition to the scaling up of computing power. Second, task switching between the different services supported by a networking element has a major negative impact on performance. Third, fast fail-over time is critical for maintaining network connections in the event of failures. We discuss in depth the design of Raincore Group Communication Manager that addresses the forgoing requirements and provides group membership management and reliable multicast transport. It is based on a novel token-ring protocol. We prove that this protocol is formally correct, namely, it satisfies the set of formal specifications that defines the Group Membership problem. The creation of Raincore has already made a substantial impact both at Caltech and the academic community as well as in the industry. The first application is SNOW, a scalable web server cluster that is part of RAIN, a collaborative project between Caltech and JPL/NASA. The second application is RainWall, a commercial solution created by Rainfinity, a Caltech spin-off company, that provides the first fault-tolerant and scalable firewall cluster. These applications exhibit the fast fail-over response, low overhead, and near-linear scalability of the Raincore protocols. In addition, we studied fault-tolerant networking architectures. In particular, we considered efficient constructions of extra-stage fault-tolerant Multistage Interconnection Networks. Multistage Interconnection Networks provide a way to construct a larger switching network using smaller switching elements. We discovered an optimal family of constructions, in the sense that it requires the least number of extra components to tolerate multiple switching element failures. We prove that this is the only family of constructions that has this optimal fault-tolerance property.

Many applications of wireless sensor networks require collaboration among sensor nodes to achieve a common task. Moreover, this is often dynamic in nature. For instance, in multi-object tracking, sensor nodes that are tracking various moving objects must share information in order to improve the tracking quality. Thus, it is important to have a protocol that maintains group connectivity in such a setting. In this paper, we study the problem of maintaining communication paths among a group of moving agents that have interacted with one another. As its solution, we propose a data structure called the distributed collaboration graph (DCG), which is a communication graph obtained from the agent trajectories. The DCG can be constructed in a purely distributed fashion with very little cost and can be used for group discovery and for multicasting/broadcasting among agents. We also propose a distributed protocol which maintains a communication tree among the agents within the DCG while the agents are moving. This allows us to maintain group connectivity and provides the infrastructure for routing among the moving agents.

Cloud computing offers new computing paradigms, capacity and flexible solutions to high performance computing (HPC) applications. For example, Hardware as a Service (HaaS) allows users to provide a large number of virtual machines (VMs) for computation-intensive applications using the HaaS model. Due to the large number of VMs and electronic components in HPC system in the cloud, any fault during the execution would result in re-running the applications, which will cost time, money and energy. In this paper we presented a proactive fault tolerance (FT) approach to HPC systems in the cloud to reduce the wall-clock execution time and dollar cost in the presence of faults. We also developed a generic FT algorithm for HPC systems in the cloud. Our algorithm does not rely on a spare node prior to prediction of a failure. We also developed a cost model for executing computation-intensive applications on HPC systems in the cloud. We analysed the dollar cost of provisioning spare nodes and checkpointing FT to assess the value of our approach. Our experimental results obtained from a real cloud execution environment show that the wall-clock execution time and cost of running computation-intensive applications in cloud can be reduced by as much as 30%. The frequency of checkpointing of computation-intensive applications can be reduced up to 50% with our FT approach for HPC in the cloud compared with current FT approaches.