Cache Coherence Techniques for Multicore Processors
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Comparative Performance Evaluation of Cache-Coherent NUMA and COMA Architectures Abstract 1 Introduction
Comparative Performance Evaluation of Cache-Coherent NUMA and COMA Architectures Per Stenstromt, Truman Joe, and Anoop Gupta Computer Systems Laboratory Stanford University, CA 94305 Abstract machine. Currently, many research groups are pursuing the design and construction of such multiprocessors [12, 1, 10]. Two interesting variations of large-scale shared-memory ma- As research has progressed in this area, two interesting vari- chines that have recently emerged are cache-coherent mm- ants have emerged, namely CC-NUMA (cache-coherent non- umform-memory-access machines (CC-NUMA) and cache- uniform memory access machines) and COMA (cache-only only memory architectures (COMA). They both have dis- memory architectures). Examples of the CC-NUMA ma- tributed main memory and use directory-based cache coher- chines are the Stanford DASH multiprocessor [12] and the MIT ence. Unlike CC-NUMA, however, COMA machines auto- Alewife machine [1], while examples of COMA machines are matically migrate and replicate data at the main-memoty level the Swedish Institute of Computer Science’s Data Diffusion in cache-line sized chunks. This paper compares the perfor- Machine (DDM) [10] and Kendall Square Research’s KSR1 mance of these two classes of machines. We first present a machine [4]. qualitative model that shows that the relative performance is Common to both CC-NUMA and COMA machines are the primarily determined by two factors: the relative magnitude features of distributed main memory, scalable interconnection of capacity misses versus coherence misses, and the gramr- network, and directory-based cache coherence. Distributed hirity of data partitions in the application. We then present main memory and scalable interconnection networks are es- quantitative results using simulation studies for eight prtraUeI sential in providing the required scalable memory bandwidth, applications (including all six applications from the SPLASH while directory-based schemes provide cache coherence with- benchmark suite). -
Detailed Cache Coherence Characterization for Openmp Benchmarks
1 Detailed Cache Coherence Characterization for OpenMP Benchmarks Anita Nagarajan, Jaydeep Marathe, Frank Mueller Dept. of Computer Science, North Carolina State University, Raleigh, NC 27695-7534 [email protected], phone: (919) 515-7889 Abstract models in their implementation (e.g., [6], [13], [26], [24], [2], [7]), and they operate at different abstraction levels Past work on studying cache coherence in shared- ranging from cycle-accuracy over instruction-level to the memory symmetric multiprocessors (SMPs) concentrates on operating system interface. On the performance tuning end, studying aggregate events, often from an architecture point work mostly concentrates on program analysis to derive op- of view. However, this approach provides insufficient infor- timized code (e.g., [15], [27]). Recent processor support for mation about the exact sources of inefficiencies in paral- performance counters opens new opportunities to study the lel applications. For SMPs in contemporary clusters, ap- effect of applications on architectures with the potential to plication performance is impacted by the pattern of shared complement them with per-reference statistics obtained by memory usage, and it becomes essential to understand co- simulation. herence behavior in terms of the application program con- In this paper, we concentrate on cache coherence simu- structs — such as data structures and source code lines. lation without cycle accuracy or even instruction-level sim- The technical contributions of this work are as follows. ulation. We constrain ourselves to an SPMD programming We introduce ccSIM, a cache-coherent memory simulator paradigm on dedicated SMPs. Specifically, we assume the fed by data traces obtained through on-the-fly dynamic absence of workload sharing, i.e., only one application runs binary rewriting of OpenMP benchmarks executing on a on a node, and we enforce a one-to-one mapping between Power3 SMP node. -
Analysis and Optimization of I/O Cache Coherency Strategies for Soc-FPGA Device
Analysis and Optimization of I/O Cache Coherency Strategies for SoC-FPGA Device Seung Won Min Sitao Huang Mohamed El-Hadedy Electrical and Computer Engineering Electrical and Computer Engineering Electrical and Computer Engineering University of Illinois University of Illinois California State Polytechnic University Urbana, USA Urbana, USA Ponoma, USA [email protected] [email protected] [email protected] Jinjun Xiong Deming Chen Wen-mei Hwu IBM T.J. Watson Research Center Electrical and Computer Engineering Electrical and Computer Engineering Yorktown Heights, USA University of Illinois University of Illinois [email protected] Urbana, USA Urbana, USA [email protected] [email protected] Abstract—Unlike traditional PCIe-based FPGA accelerators, However, choosing the right I/O cache coherence method heterogeneous SoC-FPGA devices provide tighter integrations for different applications is a challenging task because of between software running on CPUs and hardware accelerators. it’s versatility. By choosing different methods, they can intro- Modern heterogeneous SoC-FPGA platforms support multiple I/O cache coherence options between CPUs and FPGAs, but these duce different types of overheads. Depending on data access options can have inadvertent effects on the achieved bandwidths patterns, those overheads can be amplified or diminished. In depending on applications and data access patterns. To provide our experiments, we find using different I/O cache coherence the most efficient communications between CPUs and accelera- methods can vary overall application execution times at most tors, understanding the data transaction behaviors and selecting 3.39×. This versatility not only makes designers hard to decide the right I/O cache coherence method is essential. -
Chapter 5 Thread-Level Parallelism
Chapter 5 Thread-Level Parallelism Instructor: Josep Torrellas CS433 Copyright Josep Torrellas 1999, 2001, 2002, 2013 1 Progress Towards Multiprocessors + Rate of speed growth in uniprocessors saturated + Wide-issue processors are very complex + Wide-issue processors consume a lot of power + Steady progress in parallel software : the major obstacle to parallel processing 2 Flynn’s Classification of Parallel Architectures According to the parallelism in I and D stream • Single I stream , single D stream (SISD): uniprocessor • Single I stream , multiple D streams(SIMD) : same I executed by multiple processors using diff D – Each processor has its own data memory – There is a single control processor that sends the same I to all processors – These processors are usually special purpose 3 • Multiple I streams, single D stream (MISD) : no commercial machine • Multiple I streams, multiple D streams (MIMD) – Each processor fetches its own instructions and operates on its own data – Architecture of choice for general purpose mps – Flexible: can be used in single user mode or multiprogrammed – Use of the shelf µprocessors 4 MIMD Machines 1. Centralized shared memory architectures – Small #’s of processors (≈ up to 16-32) – Processors share a centralized memory – Usually connected in a bus – Also called UMA machines ( Uniform Memory Access) 2. Machines w/physically distributed memory – Support many processors – Memory distributed among processors – Scales the mem bandwidth if most of the accesses are to local mem 5 Figure 5.1 6 Figure 5.2 7 2. Machines w/physically distributed memory (cont) – Also reduces the memory latency – Of course interprocessor communication is more costly and complex – Often each node is a cluster (bus based multiprocessor) – 2 types, depending on method used for interprocessor communication: 1. -
2.2 Adaptive Routing Algorithms and Router Design 20
https://theses.gla.ac.uk/ Theses Digitisation: https://www.gla.ac.uk/myglasgow/research/enlighten/theses/digitisation/ This is a digitised version of the original print thesis. Copyright and moral rights for this work are retained by the author A copy can be downloaded for personal non-commercial research or study, without prior permission or charge This work cannot be reproduced or quoted extensively from without first obtaining permission in writing from the author The content must not be changed in any way or sold commercially in any format or medium without the formal permission of the author When referring to this work, full bibliographic details including the author, title, awarding institution and date of the thesis must be given Enlighten: Theses https://theses.gla.ac.uk/ [email protected] Performance Evaluation of Distributed Crossbar Switch Hypermesh Sarnia Loucif Dissertation Submitted for the Degree of Doctor of Philosophy to the Faculty of Science, Glasgow University. ©Sarnia Loucif, May 1999. ProQuest Number: 10391444 All rights reserved INFORMATION TO ALL USERS The quality of this reproduction is dependent upon the quality of the copy submitted. In the unlikely event that the author did not send a com plete manuscript and there are missing pages, these will be noted. Also, if material had to be removed, a note will indicate the deletion. uest ProQuest 10391444 Published by ProQuest LLO (2017). Copyright of the Dissertation is held by the Author. All rights reserved. This work is protected against unauthorized copying under Title 17, United States C ode Microform Edition © ProQuest LLO. ProQuest LLO. -
Parallel Computer Architecture
Parallel Computer Architecture Introduction to Parallel Computing CIS 410/510 Department of Computer and Information Science Lecture 2 – Parallel Architecture Outline q Parallel architecture types q Instruction-level parallelism q Vector processing q SIMD q Shared memory ❍ Memory organization: UMA, NUMA ❍ Coherency: CC-UMA, CC-NUMA q Interconnection networks q Distributed memory q Clusters q Clusters of SMPs q Heterogeneous clusters of SMPs Introduction to Parallel Computing, University of Oregon, IPCC Lecture 2 – Parallel Architecture 2 Parallel Architecture Types • Uniprocessor • Shared Memory – Scalar processor Multiprocessor (SMP) processor – Shared memory address space – Bus-based memory system memory processor … processor – Vector processor bus processor vector memory memory – Interconnection network – Single Instruction Multiple processor … processor Data (SIMD) network processor … … memory memory Introduction to Parallel Computing, University of Oregon, IPCC Lecture 2 – Parallel Architecture 3 Parallel Architecture Types (2) • Distributed Memory • Cluster of SMPs Multiprocessor – Shared memory addressing – Message passing within SMP node between nodes – Message passing between SMP memory memory nodes … M M processor processor … … P … P P P interconnec2on network network interface interconnec2on network processor processor … P … P P … P memory memory … M M – Massively Parallel Processor (MPP) – Can also be regarded as MPP if • Many, many processors processor number is large Introduction to Parallel Computing, University of Oregon, -
Adaptive Parallelism for Coupled, Multithreaded Message-Passing Programs Samuel K
University of New Mexico UNM Digital Repository Computer Science ETDs Engineering ETDs Fall 12-1-2018 Adaptive Parallelism for Coupled, Multithreaded Message-Passing Programs Samuel K. Gutiérrez Follow this and additional works at: https://digitalrepository.unm.edu/cs_etds Part of the Numerical Analysis and Scientific omputC ing Commons, OS and Networks Commons, Software Engineering Commons, and the Systems Architecture Commons Recommended Citation Gutiérrez, Samuel K.. "Adaptive Parallelism for Coupled, Multithreaded Message-Passing Programs." (2018). https://digitalrepository.unm.edu/cs_etds/95 This Dissertation is brought to you for free and open access by the Engineering ETDs at UNM Digital Repository. It has been accepted for inclusion in Computer Science ETDs by an authorized administrator of UNM Digital Repository. For more information, please contact [email protected]. Samuel Keith Guti´errez Candidate Computer Science Department This dissertation is approved, and it is acceptable in quality and form for publication: Approved by the Dissertation Committee: Professor Dorian C. Arnold, Chair Professor Patrick G. Bridges Professor Darko Stefanovic Professor Alexander S. Aiken Patrick S. McCormick Adaptive Parallelism for Coupled, Multithreaded Message-Passing Programs by Samuel Keith Guti´errez B.S., Computer Science, New Mexico Highlands University, 2006 M.S., Computer Science, University of New Mexico, 2009 DISSERTATION Submitted in Partial Fulfillment of the Requirements for the Degree of Doctor of Philosophy Computer Science The University of New Mexico Albuquerque, New Mexico December 2018 ii ©2018, Samuel Keith Guti´errez iii Dedication To my beloved family iv \A Dios rogando y con el martillo dando." Unknown v Acknowledgments Words cannot adequately express my feelings of gratitude for the people that made this possible. -
Detecting False Sharing Efficiently and Effectively
W&M ScholarWorks Arts & Sciences Articles Arts and Sciences 2016 Cheetah: Detecting False Sharing Efficiently andff E ectively Tongping Liu Univ Texas San Antonio, Dept Comp Sci, San Antonio, TX 78249 USA; Xu Liu Coll William & Mary, Dept Comp Sci, Williamsburg, VA 23185 USA Follow this and additional works at: https://scholarworks.wm.edu/aspubs Recommended Citation Liu, T., & Liu, X. (2016, March). Cheetah: Detecting false sharing efficiently and effectively. In 2016 IEEE/ ACM International Symposium on Code Generation and Optimization (CGO) (pp. 1-11). IEEE. This Article is brought to you for free and open access by the Arts and Sciences at W&M ScholarWorks. It has been accepted for inclusion in Arts & Sciences Articles by an authorized administrator of W&M ScholarWorks. For more information, please contact [email protected]. Cheetah: Detecting False Sharing Efficiently and Effectively Tongping Liu ∗ Xu Liu ∗ Department of Computer Science Department of Computer Science University of Texas at San Antonio College of William and Mary San Antonio, TX 78249 USA Williamsburg, VA 23185 USA [email protected] [email protected] Abstract 1. Introduction False sharing is a notorious performance problem that may Multicore processors are ubiquitous in the computing spec- occur in multithreaded programs when they are running on trum: from smart phones, personal desktops, to high-end ubiquitous multicore hardware. It can dramatically degrade servers. Multithreading is the de-facto programming model the performance by up to an order of magnitude, significantly to exploit the massive parallelism of modern multicore archi- hurting the scalability. Identifying false sharing in complex tectures. -
Reducing Cache Coherence Traffic with a NUMA-Aware Runtime Approach
This article has been accepted for publication in a future issue of this journal, but has not been fully edited. Content may change prior to final publication. Citation information: DOI 10.1109/TPDS.2017.2787123, IEEE Transactions on Parallel and Distributed Systems IEEE TRANSACTIONS ON PARALLEL AND DISTRIBUTED SYSTEMS, VOL. XX, NO. X, MONTH YEAR 1 Reducing Cache Coherence Traffic with a NUMA-Aware Runtime Approach Paul Caheny, Lluc Alvarez, Said Derradji, Mateo Valero, Fellow, IEEE, Miquel Moreto,´ Marc Casas Abstract—Cache Coherent NUMA (ccNUMA) architectures are a widespread paradigm due to the benefits they provide for scaling core count and memory capacity. Also, the flat memory address space they offer considerably improves programmability. However, ccNUMA architectures require sophisticated and expensive cache coherence protocols to enforce correctness during parallel executions, which trigger a significant amount of on- and off-chip traffic in the system. This paper analyses how coherence traffic may be best constrained in a large, real ccNUMA platform comprising 288 cores through the use of a joint hardware/software approach. For several benchmarks, we study coherence traffic in detail under the influence of an added hierarchical cache layer in the directory protocol combined with runtime managed NUMA-aware scheduling and data allocation techniques to make most efficient use of the added hardware. The effectiveness of this joint approach is demonstrated by speedups of 3.14x to 9.97x and coherence traffic reductions of up to 99% in comparison to NUMA-oblivious scheduling and data allocation. Index Terms—Cache Coherence, NUMA, Task-based programming models F 1 INTRODUCTION HE ccNUMA approach to memory system architecture the data is allocated within the NUMA regions of the system T has become a ubiquitous choice in the design-space [10], [28]. -
Thread-Level Parallelism – Part 1
Chapter 5: Thread-Level Parallelism – Part 1 Introduction What is a parallel or multiprocessor system? Why parallel architecture? Performance potential Flynn classification Communication models Architectures Centralized shared-memory Distributed shared-memory Parallel programming Synchronization Memory consistency models What is a parallel or multiprocessor system? Multiple processor units working together to solve the same problem Key architectural issue: Communication model Why parallel architectures? Absolute performance Technology and architecture trends Dennard scaling, ILP wall, Moore’s law Multicore chips Connect multicore together for even more parallelism Performance Potential Amdahl's Law is pessimistic Let s be the serial part Let p be the part that can be parallelized n ways Serial: SSPPPPPP 6 processors: SSP P P P P P Speedup = 8/3 = 2.67 1 T(n) = s+p/n As n → , T(n) → 1 s Pessimistic Performance Potential (Cont.) Gustafson's Corollary Amdahl's law holds if run same problem size on larger machines But in practice, we run larger problems and ''wait'' the same time Performance Potential (Cont.) Gustafson's Corollary (Cont.) Assume for larger problem sizes Serial time fixed (at s) Parallel time proportional to problem size (truth more complicated) Old Serial: SSPPPPPP 6 processors: SSPPPPPP PPPPPP PPPPPP PPPPPP PPPPPP PPPPPP Hypothetical Serial: SSPPPPPP PPPPPP PPPPPP PPPPPP PPPPPP PPPPPP Speedup = (8+5*6)/8 = 4.75 T'(n) = s + n*p; T'() → !!!! How does your algorithm ''scale up''? Flynn classification Single-Instruction Single-Data -
Leaper: a Learned Prefetcher for Cache Invalidation in LSM-Tree Based Storage Engines
Leaper: A Learned Prefetcher for Cache Invalidation in LSM-tree based Storage Engines ∗ Lei Yang1 , Hong Wu2, Tieying Zhang2, Xuntao Cheng2, Feifei Li2, Lei Zou1, Yujie Wang2, Rongyao Chen2, Jianying Wang2, and Gui Huang2 fyang lei, [email protected] fhong.wu, tieying.zhang, xuntao.cxt, lifeifei, zhencheng.wyj, rongyao.cry, beilou.wjy, [email protected] Peking University1 Alibaba Group2 ABSTRACT 101 Hit ratio Frequency-based cache replacement policies that work well QPS on page-based database storage engines are no longer suffi- Latency cient for the emerging LSM-tree (Log-Structure Merge-tree) based storage engines. Due to the append-only and copy- 100 on-write techniques applied to accelerate writes, the state- of-the-art LSM-tree adopts mutable record blocks and issues Normalized value frequent background operations (i.e., compaction, flush) to reorganize records in possibly every block. As a side-effect, 0 50 100 150 200 such operations invalidate the corresponding entries in the Time (s) Figure 1: Cache hit ratio and system performance churn (QPS cache for each involved record, causing sudden drops on the and latency of 95th percentile) caused by cache invalidations. cache hit rates and spikes on access latency. Given the ob- with notable examples including LevelDB [10], HBase [2], servation that existing methods cannot address this cache RocksDB [7] and X-Engine [14] for its superior write perfor- invalidation problem, we propose Leaper, a machine learn- mance. These storage engines usually come with row-level ing method to predict hot records in an LSM-tree storage and block-level caches to buffer hot records in main mem- engine and prefetch them into the cache without being dis- ory. -
Parallel Processors and Cache Coherency
Intro Cache Coherency Notes Computer Architecture II Parallel Processors and Cache Coherency Syed Asad Alam School of Computer Science and Statistics 1/31 Intro Cache Coherency Notes Introduction 2/31 Intro Cache Coherency Notes Flynn’s Taxonomy Introduced by M. J. Flynn SISD → Single processor with a single instruction stream and a single memory (Uniprocessors) SIMD → Single machine instruction with multiple processing elements operating on independent set of data MISD → Multiple processors, each of which execute different instruction sequence on a single sequence of data MIMD → Multiple processors execute different instruction sequences on different data sets 3/31 Intro Cache Coherency Notes Flynn’s Taxonomy Introduced by M. J. Flynn SISD → Single processor with a single instruction stream and a single memory (Uniprocessors) SIMD → Single machine instruction with multiple processing elements operating on independent set of data MISD → Multiple processors, each of which execute different instruction sequence on a single sequence of data MIMD → Multiple processors execute different instruction sequences on different data sets Text sourced from: Computer Organization and Architecture Designing for Performance, William Stallings, Chapter 17 & 18 3/31 Intro Cache Coherency Notes Flynn’s Taxonomy1 1 W. Stallings 4/31 Intro Cache Coherency Notes Flynn’s Taxonomy2 2 W. Stallings 5/31 Intro Cache Coherency Notes Multi-Computer/Cluster – Loosely Coupled 6/31 Intro Cache Coherency Notes Multi-Computer/Cluster – Loosely Coupled 6/31 Intro Cache Coherency Notes Cluster Computer Architecture3 3 W. Stallings 7/31 Intro Cache Coherency Notes Example IITAC Cluster [in Lloyd building] 346 x IBM e326 compute node each with 2 x 2.4GHz 64bit AMD Opteron 250 CPUs, 4GB RAM, ..