Performance Models for Dynamic Tuning of Parallel Applications on Computational Grids

Genaro Costa
(Universitat Autònoma de Barcelona)
Josep Jorba
(Universitat Oberta de Catalunya)
Anna Morajko
(Universitat Autònoma de Barcelona)
Tomas Margalef
(Universitat Autònoma de Barcelona)
Emilio Luque
(Universitat Autònoma de Barcelona)

Performance is a main issue in parallel application development. Dynamic tuning is 
a technique that acts over application parameters to raise execution performance 
indexes. To perform that, it is necessary to collect measurements, analyze application 
behavior using a performance model and carry out tuning actions. Computational Grids 
present proclivity for dynamic changes on their features during application execution. 
So, dynamic tuning tools are indispensable to reach the expected performance indexes 
on those environments. A particular problem that provokes performance bottlenecks is 
the load distribution in master/worker applications. This paper addresses the modeling 
of performance of such applications on Computational Grids for the perspective of 
dynamic tuning. It is inferred that grain size and number of workers are critical 
parameters to reduce execution time while raising the efficiency of resources usage. 
A heuristic to dynamically tune granularity and number of workers is proposed. The 
experimental simulated results of a matrix multiplication application in a 
heterogeneous Grid environment are shown.