Banca de DEFESA: JOÃO BATISTA FERNANDES

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : JOÃO BATISTA FERNANDES
DATE: 14/01/2020
TIME: 14:00
LOCAL: Auditório nPITI
TITLE:

Auto-tuning of load scheduling of granularity for multi-core processors applied to reverse time migration

KEY WORDS:

Auto-tuning, RTM, CSA, HPC, Chunk Size, Shared Memory.

PAGES: 55
BIG AREA: Ciências Exatas e da Terra
AREA: Ciência da Computação
SUMMARY:

Reverse time migration (RTM) is an algorithm widely used in the oil and gas industry to process seismic data. It is a computationally intensive task that suits well in parallel computers. Because of it being massive and regular, this type of task is often equally and statically distributed among the available parallel workers. However, this strategy is often not optimal. When the workers are heterogeneous, and even when most have similar processing power, many of them might still have to wait idly for the slower workers. In this paper, we show that even small performance differences between homogeneous cores can considerably affect the overall performance of a 3D RTM application. We show that dynamic load distribution has a significant advantage over the conventional static distribution, and others defaults OpenMP scheduling, auto and guided. However, the granularity of the dynamically distributed chunks of work plays a key role in harvesting this advantage. In order to find the optimal granularity, we propose a coupled simulated annealing (CSA) based auto-tuning strategy that adjusts the chunk size of work that OpenMP parallel loops assign dynamically to worker threads during the initialization of a 3D RTM application. Experiments performed on computational systems with different processor and RAM specifications and for different sizes of input show that the proposed method is consistently better than the default OpenMP loop schedulers.

BANKING MEMBERS:
Presidente - 1673543 - SAMUEL XAVIER DE SOUZA
Interno - 009.071.370-24 - TIAGO TAVARES LEITE BARROS - UNICAMP
Externa ao Programa - 1434796 - IDALMIS MILIAN SARDINA MARTINS
Externo à Instituição - HUGO ALEXANDRE DANTAS DO NASCIMENTO - UFG