Energy efficiency and consumption are currently
the challenging issues in current Petascale and in
designing future Exascale systems. The European Union
Horizon 2020 project READEX (Runtime Exploitation of
Application Dynamism for Energy-efficient Exascale computing)
develops a tools-aided online approach to analyze
and auto-tune HPC applications for energy efficiency on
Exascale systems. It exploits dynamism that occurs due to
the variation in the application behavior between iterations
of the time loop as well as changing control flow within the
time loop. This paper describes the readex_interphase tuning
plugin, which analyzes the inter-loop dynamism. The plugin
performs clustering using DBSCAN for normalized PAPI
metrics, and computes the best tuning parameter settings
for each cluster. It verifies the cluster analysis results, and
finally computes static and dynamic savings. The inter-phase
tuning strategy was evaluated for miniMD and INDEED, and
the energy savings obtained validate the effectiveness of this
methodology.
«