José Miguel-Alonso

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Cloud computing environments allow customers to dynamically scale their applications. The key problem is how to lease the right amount of resources, on a pay-as-you-go basis. Application re-dimensioning can be implemented effortlessly, adapting the resources assigned to the application to the incoming user demand. However, the identification of the right(More)
Many current parallel computers are built around a torus interconnection network. Machines from Cray, HP, and IBM, among others, make use of this topology. In terms of topological advantages, square (2D) or cubic (3D) tori would be the topologies of choice. However, for different practical reasons, 2D and 3D tori with different number of nodes per dimension(More)
The high performance computing landscape is shifting from collections of homogeneous nodes towards heterogeneous systems, in which nodes consist of a combination of traditional out-of-order execution cores and accelerator devices. Accelerators, built around GPUs, many-core chips, FPGAs or DSPs, are used to offload compute-intensive tasks. The advent of this(More)
This paper addresses the utilization of traces taken from MPI applications to do simulation-based performance studies of parallel computing systems. Different mechanisms to capture traces are discussed, pointing out important limitations of some of them. One of these limitations is the invisibility of message interchanges in collective operations, which is(More)
SpiNNaker is a massively parallel architecture designed to model large-scale spiking neural networks in (biological) real-time. Its design is based around <i>ad-hoc</i> multi-core System-on-Chips which are interconnected using a two-dimensional toroidal triangular mesh. Neurons are modeled in software and their spikes generate packets that propagate through(More)
Traditional centralized monitoring systems do not scale to present-day large, complex, networkcomputing systems. Based on recent SNMP standards for distributed management, this paper addresses the scalability problem through distribution of monitoring tasks, applicable for tools such as SIMONE (SNMP-based monitoring prototype implemented by the authors).(More)
In this paper we introduce TrGen, a traffic generation environment specifically designed to interact with simulators of interconnection networks for parallel and distributed systems. This environment is able to generate synthetic traffic, and actual traffic taken from traces (of previous program runs). It can also cooperate with complete-system simulators(More)