An Introduction to Gpus, CUDA and Opencl
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Other Apis What’S Wrong with Openmp?
Threaded Programming Other APIs What’s wrong with OpenMP? • OpenMP is designed for programs where you want a fixed number of threads, and you always want the threads to be consuming CPU cycles. – cannot arbitrarily start/stop threads – cannot put threads to sleep and wake them up later • OpenMP is good for programs where each thread is doing (more-or-less) the same thing. • Although OpenMP supports C++, it’s not especially OO friendly – though it is gradually getting better. • OpenMP doesn’t support other popular base languages – e.g. Java, Python What’s wrong with OpenMP? (cont.) Can do this Can do this Can’t do this Threaded programming APIs • Essential features – a way to create threads – a way to wait for a thread to finish its work – a mechanism to support thread private data – some basic synchronisation methods – at least a mutex lock, or atomic operations • Optional features – support for tasks – more synchronisation methods – e.g. condition variables, barriers,... – higher levels of abstraction – e.g. parallel loops, reductions What are the alternatives? • POSIX threads • C++ threads • Intel TBB • Cilk • OpenCL • Java (not an exhaustive list!) POSIX threads • POSIX threads (or Pthreads) is a standard library for shared memory programming without directives. – Part of the ANSI/IEEE 1003.1 standard (1996) • Interface is a C library – no standard Fortran interface – can be used with C++, but not OO friendly • Widely available – even for Windows – typically installed as part of OS – code is pretty portable • Lots of low-level control over behaviour of threads • Lacks a proper memory consistency model Thread forking #include <pthread.h> int pthread_create( pthread_t *thread, const pthread_attr_t *attr, void*(*start_routine, void*), void *arg) • Creates a new thread: – first argument returns a pointer to a thread descriptor. -
Data-Level Parallelism
Fall 2015 :: CSE 610 – Parallel Computer Architectures Data-Level Parallelism Nima Honarmand Fall 2015 :: CSE 610 – Parallel Computer Architectures Overview • Data Parallelism vs. Control Parallelism – Data Parallelism: parallelism arises from executing essentially the same code on a large number of objects – Control Parallelism: parallelism arises from executing different threads of control concurrently • Hypothesis: applications that use massively parallel machines will mostly exploit data parallelism – Common in the Scientific Computing domain • DLP originally linked with SIMD machines; now SIMT is more common – SIMD: Single Instruction Multiple Data – SIMT: Single Instruction Multiple Threads Fall 2015 :: CSE 610 – Parallel Computer Architectures Overview • Many incarnations of DLP architectures over decades – Old vector processors • Cray processors: Cray-1, Cray-2, …, Cray X1 – SIMD extensions • Intel SSE and AVX units • Alpha Tarantula (didn’t see light of day ) – Old massively parallel computers • Connection Machines • MasPar machines – Modern GPUs • NVIDIA, AMD, Qualcomm, … • Focus of throughput rather than latency Vector Processors 4 SCALAR VECTOR (1 operation) (N operations) r1 r2 v1 v2 + + r3 v3 vector length add r3, r1, r2 vadd.vv v3, v1, v2 Scalar processors operate on single numbers (scalars) Vector processors operate on linear sequences of numbers (vectors) 6.888 Spring 2013 - Sanchez and Emer - L14 What’s in a Vector Processor? 5 A scalar processor (e.g. a MIPS processor) Scalar register file (32 registers) Scalar functional units (arithmetic, load/store, etc) A vector register file (a 2D register array) Each register is an array of elements E.g. 32 registers with 32 64-bit elements per register MVL = maximum vector length = max # of elements per register A set of vector functional units Integer, FP, load/store, etc Some times vector and scalar units are combined (share ALUs) 6.888 Spring 2013 - Sanchez and Emer - L14 Example of Simple Vector Processor 6 6.888 Spring 2013 - Sanchez and Emer - L14 Basic Vector ISA 7 Instr. -
CUDA by Example
CUDA by Example AN INTRODUCTION TO GENERAL-PURPOSE GPU PROGRAMMING JASON SaNDERS EDWARD KANDROT Upper Saddle River, NJ • Boston • Indianapolis • San Francisco New York • Toronto • Montreal • London • Munich • Paris • Madrid Capetown • Sydney • Tokyo • Singapore • Mexico City Sanders_book.indb 3 6/12/10 3:15:14 PM Many of the designations used by manufacturers and sellers to distinguish their products are claimed as trademarks. Where those designations appear in this book, and the publisher was aware of a trademark claim, the designations have been printed with initial capital letters or in all capitals. The authors and publisher have taken care in the preparation of this book, but make no expressed or implied warranty of any kind and assume no responsibility for errors or omissions. No liability is assumed for incidental or consequential damages in connection with or arising out of the use of the information or programs contained herein. NVIDIA makes no warranty or representation that the techniques described herein are free from any Intellectual Property claims. The reader assumes all risk of any such claims based on his or her use of these techniques. The publisher offers excellent discounts on this book when ordered in quantity for bulk purchases or special sales, which may include electronic versions and/or custom covers and content particular to your business, training goals, marketing focus, and branding interests. For more information, please contact: U.S. Corporate and Government Sales (800) 382-3419 [email protected] For sales outside the United States, please contact: International Sales [email protected] Visit us on the Web: informit.com/aw Library of Congress Cataloging-in-Publication Data Sanders, Jason. -
Bitfusion Guide to CUDA Installation Bitfusion Guides Bitfusion: Bitfusion Guide to CUDA Installation
WHITE PAPER–OCTOBER 2019 Bitfusion Guide to CUDA Installation Bitfusion Guides Bitfusion: Bitfusion Guide to CUDA Installation Table of Contents Purpose 3 Introduction 3 Some Sources of Confusion 4 So Many Prerequisites 4 Installing the NVIDIA Repository 4 Installing the NVIDIA Driver 6 Installing NVIDIA CUDA 6 Installing cuDNN 7 Speed It Up! 8 Upgrading CUDA 9 WHITE PAPER | 2 Bitfusion: Bitfusion Guide to CUDA Installation Purpose Bitfusion FlexDirect provides a GPU virtualization solution. It allows you to use the GPUs, or even partial GPUs (e.g., half of a GPU, or a quarter, or one-third of a GPU), on different servers as if they were attached to your local machine, a machine on which you can now run a CUDA application even though it has no GPUs of its own. Since Bitfusion FlexDirect software and ML/AI (machine learning/artificial intelligence) applications require other CUDA libraries and drivers, this document describes how to install the prerequisite software for both Bitfusion FlexDirect and for various ML/AI applications. If you already have your CUDA drivers and libraries installed, you can skip ahead to the chapter on installing Bitfusion FlexDirect. This document gives instruction and examples for Ubuntu, Red Hat, and CentOS systems. Introduction Bitfusion’s software tool is called FlexDirect. FlexDirect easily installs with a single command, but installing the third-party prerequisite drivers and libraries, plus any application and its prerequisite software, can seem a Gordian Knot to users new to CUDA code and ML/AI applications. We will begin untangling the knot with a table of the components involved. -
High Performance Computing Through Parallel and Distributed Processing
Yadav S. et al., J. Harmoniz. Res. Eng., 2013, 1(2), 54-64 Journal Of Harmonized Research (JOHR) Journal Of Harmonized Research in Engineering 1(2), 2013, 54-64 ISSN 2347 – 7393 Original Research Article High Performance Computing through Parallel and Distributed Processing Shikha Yadav, Preeti Dhanda, Nisha Yadav Department of Computer Science and Engineering, Dronacharya College of Engineering, Khentawas, Farukhnagar, Gurgaon, India Abstract : There is a very high need of High Performance Computing (HPC) in many applications like space science to Artificial Intelligence. HPC shall be attained through Parallel and Distributed Computing. In this paper, Parallel and Distributed algorithms are discussed based on Parallel and Distributed Processors to achieve HPC. The Programming concepts like threads, fork and sockets are discussed with some simple examples for HPC. Keywords: High Performance Computing, Parallel and Distributed processing, Computer Architecture Introduction time to solve large problems like weather Computer Architecture and Programming play forecasting, Tsunami, Remote Sensing, a significant role for High Performance National calamities, Defence, Mineral computing (HPC) in large applications Space exploration, Finite-element, Cloud science to Artificial Intelligence. The Computing, and Expert Systems etc. The Algorithms are problem solving procedures Algorithms are Non-Recursive Algorithms, and later these algorithms transform in to Recursive Algorithms, Parallel Algorithms particular Programming language for HPC. and Distributed Algorithms. There is need to study algorithms for High The Algorithms must be supported the Performance Computing. These Algorithms Computer Architecture. The Computer are to be designed to computer in reasonable Architecture is characterized with Flynn’s Classification SISD, SIMD, MIMD, and For Correspondence: MISD. Most of the Computer Architectures preeti.dhanda01ATgmail.com are supported with SIMD (Single Instruction Received on: October 2013 Multiple Data Streams). -
Opencl on Shared Memory Multicore Cpus
OpenCL on shared memory multicore CPUs Akhtar Ali, Usman Dastgeer and Christoph Kessler Book Chapter N.B.: When citing this work, cite the original article. Part of: Proceedings of the 5th Workshop on MULTIPROG -2012. E. Ayguade, B. Gaster, L. Howes, P. Stenström, O. Unsal (eds), 2012. Copyright: HiPEAC Network of Excellence Available at: Linköping University Electronic Press http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-93951 Published in: Proc. Fifth Workshop on Programmability Issues for Multi-Core Computers (MULTIPROG-2012) at HiPEAC-2012 conference, Paris, France, Jan. 2012. OpenCL for programming shared memory multicore CPUs Akhtar Ali, Usman Dastgeer, and Christoph Kessler PELAB, Dept. of Computer and Information Science, Linköping University, Sweden [email protected] {usman.dastgeer,christoph.kessler}@liu.se Abstract. Shared memory multicore processor technology is pervasive in mainstream computing. This new architecture challenges programmers to write code that scales over these many cores to exploit the full compu- tational power of these machines. OpenMP and Intel Threading Build- ing Blocks (TBB) are two of the popular frameworks used to program these architectures. Recently, OpenCL has been defined as a standard by Khronos group which focuses on programming a possibly heteroge- neous set of processors with many cores such as CPU cores, GPUs, DSP processors. In this work, we evaluate the effectiveness of OpenCL for programming multicore CPUs in a comparative case study with OpenMP and Intel TBB for five benchmark applications: matrix multiply, LU decomposi- tion, 2D image convolution, Pi value approximation and image histogram generation. The evaluation includes the effect of compiler optimizations for different frameworks, OpenCL performance on different vendors’ plat- forms and the performance gap between CPU-specific and GPU-specific OpenCL algorithms for execution on a modern GPU. -
2.5 Classification of Parallel Computers
52 // Architectures 2.5 Classification of Parallel Computers 2.5 Classification of Parallel Computers 2.5.1 Granularity In parallel computing, granularity means the amount of computation in relation to communication or synchronisation Periods of computation are typically separated from periods of communication by synchronization events. • fine level (same operations with different data) ◦ vector processors ◦ instruction level parallelism ◦ fine-grain parallelism: – Relatively small amounts of computational work are done between communication events – Low computation to communication ratio – Facilitates load balancing 53 // Architectures 2.5 Classification of Parallel Computers – Implies high communication overhead and less opportunity for per- formance enhancement – If granularity is too fine it is possible that the overhead required for communications and synchronization between tasks takes longer than the computation. • operation level (different operations simultaneously) • problem level (independent subtasks) ◦ coarse-grain parallelism: – Relatively large amounts of computational work are done between communication/synchronization events – High computation to communication ratio – Implies more opportunity for performance increase – Harder to load balance efficiently 54 // Architectures 2.5 Classification of Parallel Computers 2.5.2 Hardware: Pipelining (was used in supercomputers, e.g. Cray-1) In N elements in pipeline and for 8 element L clock cycles =) for calculation it would take L + N cycles; without pipeline L ∗ N cycles Example of good code for pipelineing: §doi =1 ,k ¤ z ( i ) =x ( i ) +y ( i ) end do ¦ 55 // Architectures 2.5 Classification of Parallel Computers Vector processors, fast vector operations (operations on arrays). Previous example good also for vector processor (vector addition) , but, e.g. recursion – hard to optimise for vector processors Example: IntelMMX – simple vector processor. -
Heterogeneous Task Scheduling for Accelerated Openmp
Heterogeneous Task Scheduling for Accelerated OpenMP ? ? Thomas R. W. Scogland Barry Rountree† Wu-chun Feng Bronis R. de Supinski† ? Department of Computer Science, Virginia Tech, Blacksburg, VA 24060 USA † Center for Applied Scientific Computing, Lawrence Livermore National Laboratory, Livermore, CA 94551 USA [email protected] [email protected] [email protected] [email protected] Abstract—Heterogeneous systems with CPUs and computa- currently requires a programmer either to program in at tional accelerators such as GPUs, FPGAs or the upcoming least two different parallel programming models, or to use Intel MIC are becoming mainstream. In these systems, peak one of the two that support both GPUs and CPUs. Multiple performance includes the performance of not just the CPUs but also all available accelerators. In spite of this fact, the models however require code replication, and maintaining majority of programming models for heterogeneous computing two completely distinct implementations of a computational focus on only one of these. With the development of Accelerated kernel is a difficult and error-prone proposition. That leaves OpenMP for GPUs, both from PGI and Cray, we have a clear us with using either OpenCL or accelerated OpenMP to path to extend traditional OpenMP applications incrementally complete the task. to use GPUs. The extensions are geared toward switching from CPU parallelism to GPU parallelism. However they OpenCL’s greatest strength lies in its broad hardware do not preserve the former while adding the latter. Thus support. In a way, though, that is also its greatest weak- computational potential is wasted since either the CPU cores ness. To enable one to program this disparate hardware or the GPU cores are left idle. -
AMD Accelerated Parallel Processing Opencl Programming Guide
AMD Accelerated Parallel Processing OpenCL Programming Guide November 2013 rev2.7 © 2013 Advanced Micro Devices, Inc. All rights reserved. AMD, the AMD Arrow logo, AMD Accelerated Parallel Processing, the AMD Accelerated Parallel Processing logo, ATI, the ATI logo, Radeon, FireStream, FirePro, Catalyst, and combinations thereof are trade- marks of Advanced Micro Devices, Inc. Microsoft, Visual Studio, Windows, and Windows Vista are registered trademarks of Microsoft Corporation in the U.S. and/or other jurisdic- tions. Other names are for informational purposes only and may be trademarks of their respective owners. OpenCL and the OpenCL logo are trademarks of Apple Inc. used by permission by Khronos. The contents of this document are provided in connection with Advanced Micro Devices, Inc. (“AMD”) products. AMD makes no representations or warranties with respect to the accuracy or completeness of the contents of this publication and reserves the right to make changes to specifications and product descriptions at any time without notice. The information contained herein may be of a preliminary or advance nature and is subject to change without notice. No license, whether express, implied, arising by estoppel or other- wise, to any intellectual property rights is granted by this publication. Except as set forth in AMD’s Standard Terms and Conditions of Sale, AMD assumes no liability whatsoever, and disclaims any express or implied warranty, relating to its products including, but not limited to, the implied warranty of merchantability, fitness for a particular purpose, or infringement of any intellectual property right. AMD’s products are not designed, intended, authorized or warranted for use as compo- nents in systems intended for surgical implant into the body, or in other applications intended to support or sustain life, or in any other application in which the failure of AMD’s product could create a situation where personal injury, death, or severe property or envi- ronmental damage may occur. -
Parallel Architectures and Algorithms for Large-Scale Nonlinear Programming
Parallel Architectures and Algorithms for Large-Scale Nonlinear Programming Carl D. Laird Associate Professor, School of Chemical Engineering, Purdue University Faculty Fellow, Mary Kay O’Connor Process Safety Center Laird Research Group: http://allthingsoptimal.com Landscape of Scientific Computing 10$ 1$ 50%/year 20%/year Clock&Rate&(GHz)& 0.1$ 0.01$ 1980$ 1985$ 1990$ 1995$ 2000$ 2005$ 2010$ Year& [Steven Edwards, Columbia University] 2 Landscape of Scientific Computing Clock-rate, the source of past speed improvements have stagnated. Hardware manufacturers are shifting their focus to energy efficiency (mobile, large10" data centers) and parallel architectures. 12" 10" 1" 8" 6" #"of"Cores" Clock"Rate"(GHz)" 0.1" 4" 2" 0.01" 0" 1980" 1985" 1990" 1995" 2000" 2005" 2010" Year" 3 “… over a 15-year span… [problem] calculations improved by a factor of 43 million. [A] factor of roughly 1,000 was attributable to faster processor speeds, … [yet] a factor of 43,000 was due to improvements in the efficiency of software algorithms.” - attributed to Martin Grotschel [Steve Lohr, “Software Progress Beats Moore’s Law”, New York Times, March 7, 2011] Landscape of Computing 5 Landscape of Computing High-Performance Parallel Architectures Multi-core, Grid, HPC clusters, Specialized Architectures (GPU) 6 Landscape of Computing High-Performance Parallel Architectures Multi-core, Grid, HPC clusters, Specialized Architectures (GPU) 7 Landscape of Computing data VM iOS and Android device sales High-Performance have surpassed PC Parallel Architectures iPhone performance -
SIMD Extensions
SIMD Extensions PDF generated using the open source mwlib toolkit. See http://code.pediapress.com/ for more information. PDF generated at: Sat, 12 May 2012 17:14:46 UTC Contents Articles SIMD 1 MMX (instruction set) 6 3DNow! 8 Streaming SIMD Extensions 12 SSE2 16 SSE3 18 SSSE3 20 SSE4 22 SSE5 26 Advanced Vector Extensions 28 CVT16 instruction set 31 XOP instruction set 31 References Article Sources and Contributors 33 Image Sources, Licenses and Contributors 34 Article Licenses License 35 SIMD 1 SIMD Single instruction Multiple instruction Single data SISD MISD Multiple data SIMD MIMD Single instruction, multiple data (SIMD), is a class of parallel computers in Flynn's taxonomy. It describes computers with multiple processing elements that perform the same operation on multiple data simultaneously. Thus, such machines exploit data level parallelism. History The first use of SIMD instructions was in vector supercomputers of the early 1970s such as the CDC Star-100 and the Texas Instruments ASC, which could operate on a vector of data with a single instruction. Vector processing was especially popularized by Cray in the 1970s and 1980s. Vector-processing architectures are now considered separate from SIMD machines, based on the fact that vector machines processed the vectors one word at a time through pipelined processors (though still based on a single instruction), whereas modern SIMD machines process all elements of the vector simultaneously.[1] The first era of modern SIMD machines was characterized by massively parallel processing-style supercomputers such as the Thinking Machines CM-1 and CM-2. These machines had many limited-functionality processors that would work in parallel. -
Introduction to Multi-Threading and Vectorization Matti Kortelainen Larsoft Workshop 2019 25 June 2019 Outline
Introduction to multi-threading and vectorization Matti Kortelainen LArSoft Workshop 2019 25 June 2019 Outline Broad introductory overview: • Why multithread? • What is a thread? • Some threading models – std::thread – OpenMP (fork-join) – Intel Threading Building Blocks (TBB) (tasks) • Race condition, critical region, mutual exclusion, deadlock • Vectorization (SIMD) 2 6/25/19 Matti Kortelainen | Introduction to multi-threading and vectorization Motivations for multithreading Image courtesy of K. Rupp 3 6/25/19 Matti Kortelainen | Introduction to multi-threading and vectorization Motivations for multithreading • One process on a node: speedups from parallelizing parts of the programs – Any problem can get speedup if the threads can cooperate on • same core (sharing L1 cache) • L2 cache (may be shared among small number of cores) • Fully loaded node: save memory and other resources – Threads can share objects -> N threads can use significantly less memory than N processes • If smallest chunk of data is so big that only one fits in memory at a time, is there any other option? 4 6/25/19 Matti Kortelainen | Introduction to multi-threading and vectorization What is a (software) thread? (in POSIX/Linux) • “Smallest sequence of programmed instructions that can be managed independently by a scheduler” [Wikipedia] • A thread has its own – Program counter – Registers – Stack – Thread-local memory (better to avoid in general) • Threads of a process share everything else, e.g. – Program code, constants – Heap memory – Network connections – File handles