Francieli Zanon Boito

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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)
The High Performance Computing (HPC) community aimed for many years to increase performance regardless of energy consumption. Until the end of the decade, a next generation of HPC systems is expected to reach sustained performances of the order of exaflops. This requires many times more performance compared to the fastest supercomputers of today. Achieving(More)
This research work investigates the peformance impact of operating systems' (OS) caching parameters on a parallel file system (PFS). Through an extensive experimental analysis, an analytical performance model is proposed in order to reflect caching effects on performance of file write operations. A qualitative and quantitative evaluation of 855 test cases(More)
In this paper, we improve the performance of server-side I/O scheduling on parallel file systems by transparently including information about the applications' access patterns. Server-side I/O scheduling is a valuable tool on multiapplication scenarios, where the applications' spatial locality suffers from interference caused by concurrent accesses to the(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)
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)
This work presents a tool for storage device profiling named SeRRa. Our tool obtains the sequential to random throughput ratio for reads and writes of different sizes. Several optimizations aim at adapting applications' access patterns in order to generate contiguous accesses for improved performance when accessing storage devices like hard disks. However,(More)
The large gap between processing and I/O speed makes the storage infrastructure of a cluster a great bottleneck for HPC applications. Parallel File Systems propose a solution to this issue by distributing data onto several servers, dividing the load of I/O operations and increasing the available bandwidth. However, most parallel file systems use a fixed(More)