SC²S Colloquium - March 24, 2017

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Date: March 24, 2017
Room: 02.07.023
Time: 3:00 pm, s.t.

Fabio Gratl: Implementation and Evaluation of Task-based Approaches for Molecular Dynamics Simulations using Quicksched and ls1-mardyn =

Large scale Molecular Dynamics Simulations are an important tool for the analysis and prediction of processes on a molecular level. Since in ev- ery timestep a huge number of pairs of particles need to interact with each other individually, there is a great potential for parallelization. Task-based approaches divide the overall work into smaller parts (tasks), describe de- pendencies and conflicts and subsequently let a scheduler take care of it at runtime. This technique offers an increased amount of flexibility. The upcoming talk presents task-based parallelization approaches for the force calculation in ls1-mardyn using Quicksched. Quicksched is a library spe- cialized in offering task-based parallelism that is less rigid than in OpenMP while supporting resource dependencies and task conflicts. Several shared-memory task schemes will be presented. Afterwards, their performance on a 60 Core Xeon Phi will be analyzed and discussed under various aspects.

Manuel Fasching: JIT compilation to realize flexible data access in simulation software

Input data or scenarios of simulation applications are frequently defined by mathematical functions. These functions are often implemented in the application’s code and are, hence, statically compiled. The dependency between scenario implementations and the actual application causes an adaption of the application’s code for every new scenario. The primary goal of this thesis is the development of a methology, based on Just-in-time compiling, capable of dissolving this dependency and enhancing the flexibility of data initialization. The absence of an easy but flexible solution was identified as the primary issue causing this dependency. A library capable of Just-in-time compiling scenarios was developed in order to solve it. This library was integrated in the simulation applications Shallow Water Equations and SeisSol. Tests validated the proper behavior and the aptitude for simulation applications of the developed library. The results show that the flexibility of data initialization can be improved by JIT compiling without causing unacceptable drawbacks.