iC2mpi: A Platform for Parallel Execution of Graph-Structured Iterative Computations

Parallelization of sequential programs is often daunting because of the substantial development cost involved. Various solutions have been proposed to address this concern, including directive-based approaches and parallelization platforms. These solutions have not always been successful, in part because many try to address all types of applications. We propose a platform for parallelization of a class of applications that have similar computational structure, namely graph-structured iterative applications. iC2mpi is a unique proof-of-concept prototype platform that provides relatively easy parallelization of existing sequential programs and facilitates experimentation with static partitioning and dynamic load balancing schemes. We demonstrate with various generic application graph topologies and an existing application, namely a time-stepped battlefield management simulation, that our platform can produce good performance with very little effort

Elastic Business Process Management: State of the Art and Open Challenges for BPM in the Cloud

With the advent of cloud computing, organizations are nowadays able to react rapidly to changing demands for computational resources. Not only individual applications can be hosted on virtual cloud infrastructures, but also complete business processes. This allows the realization of so-called elastic processes, i.e., processes which are carried out using elastic cloud resources. Despite the manifold benefits of elastic processes, there is still a lack of solutions supporting them. In this paper, we identify the state of the art of elastic Business Process Management with a focus on infrastructural challenges. We conceptualize an architecture for an elastic Business Process Management System and discuss existing work on scheduling, resource allocation, monitoring, decentralized coordination, and state management for elastic processes. Furthermore, we present two representative elastic Business Process Management Systems which are intended to counter these challenges. Based on our findings, we identify open issues and outline possible research directions for the realization of elastic processes and elastic Business Process Management.Comment: Please cite as: S. Schulte, C. Janiesch, S. Venugopal, I. Weber, and P. Hoenisch (2015). Elastic Business Process Management: State of the Art and Open Challenges for BPM in the Cloud. Future Generation Computer Systems, Volume NN, Number N, NN-NN., http://dx.doi.org/10.1016/j.future.2014.09.00

Load balancing issues in automotives

Electronic Control Units (ECUs) are widely used to improve the comfort and reliability of vehicles. It has become the fundamental building block of any automotive subsystem and is interfaced with electro mechanics counterpart. To meet the system wide requirements, these ECUs are interconnected using the communication infrastructure. Although the communication infrastructure in terms of, predominantly, the CAN based vehicle network took its birth to enable ECUs to work in a coordinated manner in order to support system wide requirements, during the past decade, this infrastructure was also viewed as a potential means to incorporate extensibility in terms of addition of newer ECUs which are built for implementing additional requirements. With this paradigm, the number of ECUs started growing in a steep manner, uncontrolled and as a result, today, it is not hard to see a high segment automotive housing ECUs as large as 75–80. Hence, load balancing mechanisms are needed to ease ECU integration and for efficient utilization of CPU power in ECUs. In this paper, we explain the concept of load balancing on the basis of CPU utilization across ECUs

Exploring coordinated software and hardware support for hardware resource allocation

Multithreaded processors are now common in the industry as they offer high performance at a low cost. Traditionally, in such processors, the assignation of hardware resources between the multiple threads is done implicitly, by the hardware policies. However, a new class of multithreaded hardware allows the explicit allocation of resources to be controlled or biased by the software. Currently, there is little or no coordination between the allocation of resources done by the hardware and the prioritization of tasks done by the software.This thesis targets to narrow the gap between the software and the hardware, with respect to the hardware resource allocation, by proposing a new explicit resource allocation hardware mechanism and novel schedulers that use the currently available hardware resource allocation mechanisms.It approaches the problem in two different types of computing systems: on the high performance computing domain, we characterize the first processor to present a mechanism that allows the software to bias the allocation hardware resources, the IBM POWER5. In addition, we propose the use of hardware resource allocation as a way to balance high performance computing applications. Finally, we propose two new scheduling mechanisms that are able to transparently and successfully balance applications in real systems using the hardware resource allocation. On the soft real-time domain, we propose a hardware extension to the existing explicit resource allocation hardware and, in addition, two software schedulers that use the explicit allocation hardware to improve the schedulability of tasks in a soft real-time system.In this thesis, we demonstrate that system performance improves by making the software aware of the mechanisms to control the amount of resources given to each running thread. In particular, for the high performance computing domain, we show that it is possible to decrease the execution time of MPI applications biasing the hardware resource assignation between threads. In addition, we show that it is possible to decrease the number of missed deadlines when scheduling tasks in a soft real-time SMT system.Postprint (published version