Ray Tracing acceleration through a custom scheduling policy to take advantage of the cache affinity in a Linux-based Special-Purpose Operating System

Proyecto de Graduación (Maestría en Electrónica) Instituto Tecnológico de Costa Rica, Escuela de Ingeniería Electrónica, 2021Esta investigación explora el beneficio de diseñar una política de calendarizacion personalizada que reduzca el tiempo de de ejecución de cargas computacionalmente intensivas. Cargas computacionalmente intensivas tales como ray tracing, son sensibles al cambio de contexto producido por el calendarizador. La política de calendarización propuesta asigna afinidad de cache fuerte para reducir el cambio de contexto al permitir que cada hilo tenga asignado un único núcleo para su ejecución. Utilizando un sistema operativo de propósito especifico, hipotéticamente, el sistema tendrá un mayor rendimiento al combinarlo con la política de calendarización personalizada. El algoritmo de ray tracing fue seleccionado como carga computacionalmente intensiva para comparar su rendimiento en un sistema operativo de propósito especifico contra un sistema operativo de propósito general con su configuración por defecto. Comparado a la referencia, ANOVA factorial confirmo un 19% de reducción en el tiempo de sintetizado promedio al usar la política de calendarización personalizada en un sistema operativo de propósito especifico.The present research explores the benefit of designing a custom scheduling policy to reduce the execution time for computationally intensive workloads. Computationally intensive workloads, such as, ray tracing, are sensible to the context switching produced by the scheduler. The proposed custom scheduling policy assigns hard cache affinity to reduce the context switching by allowing each thread to use only one core during the process execution. Utilizing a special-purpose operating system will hypothetically boost the reduced execution time by integrating the custom scheduling policy. Ray tracing algorithm was selected as the computationally intensive workload to compare its performance in the special-purpose operating system with the custom scheduling policy against a generalpurpose operating system with the default configuration. Compared to the baseline, the factorial ANOVA test confirmed an average 19% reduction of the rendering time using the custom scheduling policy in a special-purpose operating system

PGGA: A predictable and grouped genetic algorithm for job scheduling

This paper presents a predictable and grouped genetic algorithm (PGGA) for job scheduling. The novelty of the PGGA is twofold: (1) a job workload estimation algorithm is designed to estimate a job workload based on its historical execution records, (2) the divisible load theory (DLT) is employed to predict an optimal fitness value by which the PGGA speeds up the convergence process in searching a large scheduling space. Comparison with traditional scheduling methods such as first-come-first-serve (FCFS) and random scheduling, heuristics such as a typical genetic algorithm, Min-Min and Max-Min indicates that the PGGA is more effective and efficient in finding optimal scheduling solutions

Efficient Generation of Parallel Spin-images Using Dynamic Loop Scheduling

High performance computing (HPC) systems underwent a significant increase in their processing capabilities. Modern HPC systems combine large numbers of homogeneous and heterogeneous computing resources. Scalability is, therefore, an essential aspect of scientific applications to efficiently exploit the massive parallelism of modern HPC systems. This work introduces an efficient version of the parallel spin-image algorithm (PSIA), called EPSIA. The PSIA is a parallel version of the spin-image algorithm (SIA). The (P)SIA is used in various domains, such as 3D object recognition, categorization, and 3D face recognition. EPSIA refers to the extended version of the PSIA that integrates various well-known dynamic loop scheduling (DLS) techniques. The present work: (1) Proposes EPSIA, a novel flexible version of PSIA; (2) Showcases the benefits of applying DLS techniques for optimizing the performance of the PSIA; (3) Assesses the performance of the proposed EPSIA by conducting several scalability experiments. The performance results are promising and show that using well-known DLS techniques, the performance of the EPSIA outperforms the performance of the PSIA by a factor of 1.2 and 2 for homogeneous and heterogeneous computing resources, respectively

Distributed Simulation of Large-Scale Individual Oriented Models

The distributed simulation for high performance models has been carried-out into a very useful and low-cost tool. In the present work their application to an individual oriented model (Fish Schools) is analyzed. To do this, it was analyzed different alternatives for this type of simulation and their application to obtain performance and model scalability using different implementation. Thus, two distributed simulator have been developed based on PVM and MPI communication libraries. This paper resumes the advantages and drawbacks of each implementation and some conclusions about the distributed simulation for this type of models are extracted. Moreover, visualization aspects and the developed infrastructure based on OpenGl are described.Facultad de Informátic

A framework for realistic real-time walkthroughs in a VR distributed environment

Virtual and augmented reality (VR/AR) are increasingly being used in various business scenarios and are important driving forces in technology development. However the usage of these technologies in the home environment is restricted due to several factors including lack of low-cost (from the client point of view) highperformance solutions. In this paper we present a general client/server rendering architecture based on Real-Time concepts, including support for a wide range of client platforms and applications. The idea of focusing on the real-time behaviour of all components involved in distributed IP-based VR scenarios is new and has not been addressed before, except for simple sub-solutions. This is considered as “the most significant problem with the IP environment” [1]. Thus, the most important contribution of this research will be the holistic approach, in which networking, end-systems and rendering aspects are integrated into a cost-effective infrastructure for building distributed real-time VR applications on IP-based networks

A hybrid approach to Enhancing Process Scheduling in multiple core Systems

Process scheduling within computer systems and with regards to the CPU always encounters bottle necks due to over reliance on single processor scheduling techniques. The presence of multicore processor systems attempts to increase throughput without however operating at full optimum capacity, hence the need for the proposal of a more efficient scheduling approach for use in multiple core systems. This paper conducted a comparative analysis of the rate of efficiency of existing scheduling algorithms with the aid of secondary data. It then employed CPU user benchmark analysis to asses the effectiveness of the proposed approach. Quad-core processor systems are most suitable for the proposed approach which basically implements two approaches one where scheduling decisions are handled by a master processor while other processors execute the user code thus always ensuring that all processors are busy and always utilized. Keywords: Process scheduling, multicore systems, system optimization DOI: 10.7176/JIEA/11-2-04 Publication date: May 30th 202

Developing An Object-oriented Approach For Operations Simulation In Speedes

Using simulation techniques, performance of any proposed system can be tested for different scenarios with a generated model. However, it is difficult to rapidly create simulation models that will accurately represent the complexity of the system. In recent years, Object-Oriented Discrete-Event Simulation has emerged as the potential technology to implement rapid simulation schemes. A number of software based on programming languages like C++ and Java are available for carrying out Object Oriented Discrete-Event Simulation. These software packages establish a general framework for simulation in computer programs, but need to be further customized for desired end-use applications. In this thesis, a generic simulation library is created for the distributed Synchronous Parallel Environment for Emulation and Discrete-Event Simulation (SPEEDES). This library offers classes to model the functionality of servers, processes, resources, transporters, and decisions. The library is expected to produce efficient simulation models in less time and with a lesser amount of coding. The class hierarchy is modeled using the Unified Modeling Language (UML). To test the library, the existing SPEEDES Space Shuttle Model is enhanced and recreated. This enhanced model is successfully validated against the original Arena model