2-6 March 2009
Le Ciminiere, Catania, Sicily, Italy
Europe/Rome timezone

Porting AITALC product through a master/worker scheme

4 Mar 2009, 14:00
20m
Raffaello (80) (Le Ciminiere, Catania, Sicily, Italy)

Raffaello (80)

Le Ciminiere, Catania, Sicily, Italy

Viale Africa 95100 Catania
Oral Experiences from application porting and deployment High Energy Physics

Speaker

Dr Alejandro Lorca (Universidad Complutense de Madrid)

Description

A program calculating Bhabha scattering at High Energy Physics is considered for being ported into the EGEE infrastructure. The program, which is a result of the AITALC project, computes integrated cross sections and its first order quantum corrections for the electroweak Standard Model. The job submission, execution and monitoring are implemented through the GRIDWAY metascheduler.

Detailed analysis

AITALC is a useful tool for automating calculations needed in High Energy Physics. Using this package we chose the interesting process of electron-positron scattering, and considered the final executable delivering numerical results for porting into a grid environment. We have learned under which conditions porting is feasible, and also the gain achievable in the EGEE infrastructure.
The porting of the application was done with the help of the GRIDWAY metascheduler. A scheme of master/worker was developed where the master remain at the user's side, giving instructions through GRIDWAY about how the submission should be partitioned and managed. Because the code created by AITALC is a dynamically linked executable, a few modifications to the original were required. These modifications allowed the worker to run as a static binary accepting input arguments under different configurations at each grid node. Finally, some postprocessing utilities and improvements were implemented.

Impact

HEP applications mainly use GRID resources via data collection and analyses from LHC events and simulations. Theoreticians also require heavy computational tasks to match the same level of accuracy achieved by the experimental measurements. The products generated by AITALC are codes behaving as many other automated tools in the community, and serving as a good candidate to understand and exploit the parallelization capabilities of a typical calculation at high energy colliders.
We consider this example specially useful as a test ground for other, more complex and cumbersome, theoretical calculations strongly needing speed-ups without data loss.

Keywords

grid, application porting, HEP

Conclusions and Future Work

The porting was succesfully implemented and different workload balances was studied with respect to performance. It turned out that the master/worker method requires a reasonably small amount of user intervention in the worker code and allows the user prepare the master according to the output needs. Further work at the master includes fine-graining of data results through automated feedback and the adoption of the DRMAA standard. We propose also some improvements in AITALC.

URL for further information

http://www-zeuthen.desy.de/theory/aitalc
http://gridway.org

Primary author

Dr Alejandro Lorca (Universidad Complutense de Madrid)

Co-authors

Dr Eduardo Huedo (Universidad Complutense de Madrid) Prof. Ignacio M. Llorente (Universidad Complutense de Madrid) Dr José Luis Vázquez-Poletti (Universidad Complutense de Madrid)

Presentation Materials

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