Comparable to time performance models, it is now possible to estimate performance based upon energy consumption for HPC systems. The predictive ability of the analytical modeling is an interesting feature that motivates us to approach this methodology for the case of energy consumption. In this paper, we present an analytical model for predicting the energy consumption for the High Performance Linpack (HPL). The derived model can be used to know in advance the energy consumed by the HPL over a target architecture, and can be integrated into the schedulers of operating systems or queue managers. We established an experimental setup using a standard metered PDU that allowed us to measure the energy consumption for the HPL benchmark on our cluster. With the monitoring system in place, we can obtain the architectural and algorithmic parameters associated for both performance and energy analytical models. Also this has made possible watts and gflops-per-watt prediction when we execute Linpack executions with concrete algorithm parameters in our cluster.

In large cc-NUMA systems the efficient use of the different levels of the memory hierarchy is not an easy task, and the performance of multithreading implementations of the libraries decreases when the number of cores used increases, so producing an important lost of efficiency. To alleviate this problem, routines with multilevel parallelism can be developed by combining OpenMP and BLAS parallelism. In that way, higher performance can be achieved, but it is necessary to develop some autotuning technique for the appropriate selection of the number of threads to use at each level. The selection can be made through theoretical models of the execution time or some installation methodology. This work analyses some installation techniques for a two-level matrix multiplication routine, with the aim of developing a valid methodology for other linear algebra routines in large cc-NUMA systems. The basic ideas of the two-level parallelisation and the installation methodology are discussed and some experimental results are commented on.