Impact of Event Logger on Causal Message Logging Protocols for Fault Tolerant {MPI}

International audienceFault tolerance in MPI becomes a main issue in the HPC community. Several approaches are envisioned from user or programmer controlled fault tolerance to fully automatic fault detection and handling. For this last approach, several protocols have been proposed in the literature. In a recent paper, we have demonstrated that uncoordinated checkpointing tolerates higher fault frequency than coordinated checkpointing. Moreover causal message logging protocols have been proved the most efficient message logging technique. These protocols consist in piggybacking non deterministic events to computation message. Several protocols have been proposed in the literature. Their merits are usually evaluated from four metrics: a) piggybacking computation cost, b) piggyback size, c) applications performance and d) fault recovery performance. In this paper, we investigate the benefit of using a stable storage for logging message events in causal message logging protocols. To evaluate the advantage of this technique we implemented three protocols: 1) a classical causal message protocol proposed in Manetho, 2) a state of the art protocol known as LogOn, 3) a light computation cost protocol called Vcausal. We demonstrate a major impact of this stable storage for the three protocols, on the four criteria for micro benchmarks as well as for the NAS benchmark

A Survey of Fault-Tolerance and Fault-Recovery Techniques in Parallel Systems

Supercomputing systems today often come in the form of large numbers of commodity systems linked together into a computing cluster. These systems, like any distributed system, can have large numbers of independent hardware components cooperating or collaborating on a computation. Unfortunately, any of this vast number of components can fail at any time, resulting in potentially erroneous output. In order to improve the robustness of supercomputing applications in the presence of failures, many techniques have been developed to provide resilience to these kinds of system faults. This survey provides an overview of these various fault-tolerance techniques.Comment: 11 page

Energy efficiency in HPC with and without knowledge of applications and services

International audienceThe constant demand of raw performance in high performance computing often leads to high performance systems' over-provisioning which in turn can result in a colossal energy waste due to workload/application variation over time. Proposing energy efficient solutions in the context of large scale HPC is a real unavoidable challenge. This paper explores two alternative approaches (with or without knowledge of applications and services) dealing with the same goal: reducing the energy usage of large scale infrastructures which support HPC applications. This article describes the first approach "with knowledge of applications and services'' which enables users to choose the less consuming implementation of services. Based on the energy consumption estimation of the different implementations (protocols) for each service, this approach is validated on the case of fault tolerance service in HPC. The approach "without knowledge'' allows some intelligent framework to observe the life of HPC systems and proposes some energy reduction schemes. This framework automatically estimates the energy consumption of the HPC system in order to apply power saving schemes. Both approaches are experimentally evaluated and analyzed in terms of energy efficiency

A Survey of Checkpointing Algorithms in Mobile Ad Hoc Network

Checkpoint is defined as a fault tolerant technique that is a designated place in a program at which normal processing is interrupted specifically to preserve the status information necessary to allow resumption of processing at a later time. If there is a failure, computation may be restarted from the current checkpoint instead of repeating the computation from beginning. Checkpoint based rollback recovery is one of the widely used technique used in various areas like scientific computing, database, telecommunication and critical applications in distributed and mobile ad hoc network. The mobile ad hoc network architecture is one consisting of a set of self configure mobile hosts capable of communicating with each other without the assistance of base stations. The main problems of this environment are insufficient power and limited storage capacity, so the checkpointing is major challenge in mobile ad hoc network. This paper presents the review of the algorithms, which have been reported for checkpointing approaches in mobile ad hoc network

Scalable group-based checkpoint/restart for large-scale message-passing systems

The ever increasing number of processors used in parallel computers is making fault tolerance support in large-scale parallel systems more and more important. We discuss the inadequacies of existing system-level checkpointing solutions for message-passing applications as the system scales up. We analyze the coordination cost and blocking behavior of two current MPI implementations with checkpointing support. A group-based solution combining coordinated checkpointing and message logging is then proposed. Experiment results demonstrate its better performance and scalability than LAM/MPI and MPICH-VCL. To assist group formation, a method to analyze the communication behaviors of the application is proposed. ©2008 IEEE.published_or_final_versio

Space Reclamation for Uncoordinated Checkpointing in Message-Passing Systems

Checkpointing and rollback recovery are techniques that can provide efficient recovery from transient process failures. In a message-passing system, the rollback of a message sender may cause the rollback of the corresponding receiver, and the system needs to roll back to a consistent set of checkpoints called recovery line. If the processes are allowed to take uncoordinated checkpoints, the above rollback propagation may result in the domino effect which prevents recovery line progression. Traditionally, only obsolete checkpoints before the global recovery line can be discarded, and the necessary and sufficient condition for identifying all garbage checkpoints has remained an open problem. A necessary and sufficient condition for achieving optimal garbage collection is derived and it is proved that the number of useful checkpoints is bounded by N(N+1)/2, where N is the number of processes. The approach is based on the maximum-sized antichain model of consistent global checkpoints and the technique of recovery line transformation and decomposition. It is also shown that, for systems requiring message logging to record in-transit messages, the same approach can be used to achieve optimal message log reclamation. As a final topic, a unifying framework is described by considering checkpoint coordination and exploiting piecewise determinism as mechanisms for bounding rollback propagation, and the applicability of the optimal garbage collection algorithm to domino-free recovery protocols is demonstrated

Unified fault-tolerance framework for hybrid task-parallel message-passing applications

We present a unified fault-tolerance framework for task-parallel message-passing applications to mitigate transient errors. First, we propose a fault-tolerant message-logging protocol that only requires the restart of the task that experienced the error and transparently handles any message passing interface calls inside the task. In our experiments we demonstrate that our fault-tolerant solution has a reasonable overhead, with a maximum observed overhead of 4.5%. We also show that fine-grained parallelization is important for hiding the overheads related to the protocol as well as the recovery of tasks. Secondly, we develop a mathematical model to unify task-level checkpointing and our protocol with system-wide checkpointing in order to provide complete failure coverage. We provide closed formulas for the optimal checkpointing interval and the performance score of the unified scheme. Experimental results show that the performance improvement can be as high as 98% with the unified scheme.The author(s) disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: This work was supported by the FI-DGR 2013 scholarship and the European Community’s Seventh Framework Programme [FP7/2007-2013] under the Mont-blanc 2 Project (www.montblanc-project.eu), grant agreement no. 610402 and TIN2015-65316-P.Peer ReviewedPostprint (author's final draft