Abstract

The simulation of fabrics, clothes, and flexible materials is an essential topic in computer animation of realistic virtual humans and dynamic sceneries. New emerging technologies, as interactive digital TV and multimedia products, make necessary the development of powerful tools to perform real-time simulations. Parallelism is one of such tools. When analyzing computationally fabric simulations we found these codes belonging to the complex class of irregular applications. Frequently this kind of codes includes reduction operations in their core, so that an important fraction of the computational time is spent on such operations. In fabric simulators these operations appear when evaluating forces, giving rise to the equation system to be solved. For this reason, this paper discusses only this phase of the simulation. This paper analyzes and evaluates different irregular reduction parallelization techniques on ccNUMA shared memory machines, applied to a real, physically-based, fabric simulator we have developed. Several issues are taken into account in order to achieve high code performance, as exploitation of data access locality and parallelism, as well as careful use of memory resources (memory overhead). In this paper we use the concept of data affinity to develop various efficient algorithms for reduction parallelization exploiting data locality.

Keywords: Fabric and cloth simulation; Data locality; Irregular reductions; Parallelization techniques; ccNUMA multiprocessors

PACS: 07.05.Tp; 02.60.Cb

Article Outline

1. Introduction

2. Overview of the fabric simulation problem

2.1. Physical model

2.2. Evaluating forces

3. Irregular properties of the simulator code

3.1. Irregular reductions

3.2. Locality properties of the fabric simulator

4. Irregular reduction parallelization

4.1. Privatization-based methods

4.2. Partitioning-based methods

4.2.1. Parallelization based on write affinity

5. Experimental evaluation

6. Conclusions

References

This work was supported by Ministry of Education and Culture (CICYT), Spain, through grant TIC2003-06623.