Claudio Schepke

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This work shows how a Hybrid MPI/OpenMP implementation can improve the performance of the Ocean-Land-Atmosphere Model (OLAM) on a multi-core cluster environment, which is a typical HPC many small files workload application. Previous experiments have shown that the scalability of this application on clusters is limited by the performance of the output(More)
Atmospheric models usually demand high processing power and generate large amounts of data. As the degree of parallelism grows, the I/O operations may become the major impacting factor of their performance. This paper evaluates the Ocean-Land-Atmosphere Model (OLAM) on the PVFS file system in order to point the I/O characteristics of the application. We(More)
Despite the evolution of cloud computing in recent years, the performance and comprehensive understanding of the available private cloud tools are still under research. This paper contributes to an analysis of the Infrastructure as a Service (IaaS) domain by mapping new insights and discussing the challenges for improving cloud services. The goal is to make(More)
This paper presents a blocked parallel implementation of a three-diagonal version of the Lattice Boltzmann Method. This method is a numerical model used to represent and to simulate fluid flows through mesoscopic approaches. Parallel implementations are often adopted to attend the demand of an expressive memory amount and processing power of the method.(More)
Infrastructure-as-a-Service (IaaS) is a cloud on-demand commodity built on top of virtualization technologies and managed by IaaS tools. In this scenario, performance is a relevant matter because a set of aspects may impact and increase the system overhead. Specific on the network, the use of virtualized capabilities may cause performance degradation(More)
This paper presents the use of trace-based performance visualization of a large scale atmospheric model, the Ocean-Land-Atmosphere Model (OLAM). The trace was obtained with the libRastro library, and the visualization was done with Paj´e. The use of visualization aimed to analyze OLAM's performance and to identify its bottlenecks. Especially, we are(More)
Numerical models have been used extensively in the last decades to understand and predict weather phenomena and the climate. In general, models are classified according to their operation domain: global (entire Earth) and regional (country, state, etc). Global models have spatial resolution of about 0.2 to 1.5 degrees of latitude and therefore cannot(More)
Elasticity is considered one of the fundamental properties of cloud computing, and can be seen as the ability of a system to increase or decrease the computing resources allocated in a dynamic and on demand way. This feature is suitable for dynamic applications, whose resources requirements cannot be determined exactly in advance, either due to changes in(More)
This work evaluates the I/O performance in a multicorecluster environment for an atmosphere model for weather and climate simulations. It contains large data sets for I/Oin scientific applications. The analysis demonstrates that the scalability of the system gets worse as we increase the number of cores per machine, with greater impact on output operations.(More)
Atmospheric models usually demand high processing power and generate large amounts of data. As the degree of parallelism grows, the I/O operations may become the major impacting factor of their performance. This work shows that a hybrid MPI/OpenMP implementation can improve the performance of the atmospheric model ocean-land-atmosphere model (OLAM) on a(More)