Download or read book A Scalable Hierarchical Cache Coherence Protocol written by Deborah Anne Wallach and published by . This book was released on 1990 with total page 98 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book A Scalable Cache Coherence Protocol for a Hierarchical Bus based Multiprocessor written by Wuucheng Huang and published by . This book was released on 1990 with total page 180 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book A Scalable New Cache Coherence Protocol for Hierarchical Distributed Shared Memory written by Phanindra K. Mannava and published by . This book was released on 1994 with total page 64 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book A suite of hierarchical cache coherence protocols written by Umakishore Ramachandran and published by . This book was released on 1988 with total page 26 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Multi Core Cache Hierarchies written by Rajeev Balasubramonian and published by Morgan & Claypool Publishers. This book was released on 2011-06-06 with total page 155 pages. Available in PDF, EPUB and Kindle. Book excerpt: A key determinant of overall system performance and power dissipation is the cache hierarchy since access to off-chip memory consumes many more cycles and energy than on-chip accesses. In addition, multi-core processors are expected to place ever higher bandwidth demands on the memory system. All these issues make it important to avoid off-chip memory access by improving the efficiency of the on-chip cache. Future multi-core processors will have many large cache banks connected by a network and shared by many cores. Hence, many important problems must be solved: cache resources must be allocated across many cores, data must be placed in cache banks that are near the accessing core, and the most important data must be identified for retention. Finally, difficulties in scaling existing technologies require adapting to and exploiting new technology constraints. The book attempts a synthesis of recent cache research that has focused on innovations for multi-core processors. It is an excellent starting point for early-stage graduate students, researchers, and practitioners who wish to understand the landscape of recent cache research. The book is suitable as a reference for advanced computer architecture classes as well as for experienced researchers and VLSI engineers. Table of Contents: Basic Elements of Large Cache Design / Organizing Data in CMP Last Level Caches / Policies Impacting Cache Hit Rates / Interconnection Networks within Large Caches / Technology / Concluding Remarks

Download or read book A Multi level Hierarchical Cache Coherence Protocol for Multiprocessors written by University of Washington. Dept. of Computer Science and published by . This book was released on 1992 with total page 34 pages. Available in PDF, EPUB and Kindle. Book excerpt: Finally, we conclude with some preliminary results, and some examples of how the protocol and architecture could be made more efficient."

Download or read book Structural Design and Proof of Hierarchical Cache coherence Protocols written by Joonwon Choi and published by . This book was released on 2021 with total page 146 pages. Available in PDF, EPUB and Kindle. Book excerpt: Cache-coherence protocols have been one of the greatest correctness challenges of the hardware world. A memory subsystem usually consists of several caches and the main memory, and a cache-coherence protocol defined in such a system allows multiple memory-access transactions to execute in a distributed manner, across the levels of a cache hierarchy. This source of concurrency is the most challenging part in formal verification of cache coherence. In this dissertation, we introduce Hemiola, a framework embedded in Coq to design, prove, and synthesize cache-coherence protocols in a structural way. The framework guides the user to design protocols that never experience inconsistent inter-leavings while handling transactions concurrently. Any protocol designed in Hemiola always satisfies the serializability property, allowing a user to prove the protocol assuming that transactions are executed one-at-a-time. The proof relies on conditions on the protocol topology and state-change rules, but we have designed a domainspecific protocol language that guides the user to design protocols that satisfy these properties by construction. The framework also provides a novel way to design and prove invariants by adding predicates to messages in the system, called predicate messages. On top of serializability, it is much simpler to prove a predicate message, since it is guaranteed that the predicate is not spuriously broken by other messages. We used Hemiola to design and prove hierarchical MSI and MESI protocols, in both inclusive and noninclusive variants, as case studies. We also demonstrated that the case-study protocols are indeed hardware-synthesizable, by using a compilation/ synthesis toolchain in the framework.

Download or read book Verification of Hierarchical Cache Coherence Protocols for Futuristic Processors written by Xiaofang Chen (computer engineer.) and published by . This book was released on 2008 with total page 284 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book A Primer on Memory Consistency and Cache Coherence written by Vijay Nagarajan and published by Morgan & Claypool Publishers. This book was released on 2020-02-04 with total page 296 pages. Available in PDF, EPUB and Kindle. Book excerpt: Many modern computer systems, including homogeneous and heterogeneous architectures, support shared memory in hardware. In a shared memory system, each of the processor cores may read and write to a single shared address space. For a shared memory machine, the memory consistency model defines the architecturally visible behavior of its memory system. Consistency definitions provide rules about loads and stores (or memory reads and writes) and how they act upon memory. As part of supporting a memory consistency model, many machines also provide cache coherence protocols that ensure that multiple cached copies of data are kept up-to-date. The goal of this primer is to provide readers with a basic understanding of consistency and coherence. This understanding includes both the issues that must be solved as well as a variety of solutions. We present both high-level concepts as well as specific, concrete examples from real-world systems. This second edition reflects a decade of advancements since the first edition and includes, among other more modest changes, two new chapters: one on consistency and coherence for non-CPU accelerators (with a focus on GPUs) and one that points to formal work and tools on consistency and coherence.

Download or read book Locality aware Cache Hierarchy Management for Multicore Processors written by and published by . This book was released on 2015 with total page 194 pages. Available in PDF, EPUB and Kindle. Book excerpt: Next generation multicore processors and applications will operate on massive data with significant sharing. A major challenge in their implementation is the storage requirement for tracking the sharers of data. The bit overhead for such storage scales quadratically with the number of cores in conventional directory-based cache coherence protocols. Another major challenge is limited cache capacity and the data movement incurred by conventional cache hierarchy organizations when dealing with massive data scales. These two factors impact memory access latency and energy consumption adversely. This thesis proposes scalable efficient mechanisms that improve effective cache capacity (i.e., by improving utilization) and reduce data movement by exploiting locality and controlling replication. First, a limited directory-based protocol, ACKwise is proposed to track the sharers of data in a cost-effective manner. ACKwise leverages broadcasts to implement scalable cache coherence. Broadcast support can be implemented in a 2-D mesh network by making simple changes to its routing policy without requiring any additional virtual channels. Second, a locality-aware replication scheme that better manages the private caches is proposed. This scheme controls replication based on data reuse information and seamlessly adapts between private and logically shared caching of on-chip data at the fine granularity of cache lines. A low-overhead runtime profiling capability to measure the locality of each cache line is built into hardware. Private caching is only allowed for data blocks with high spatio-temporal locality. Third, a Timestamp-based memory ordering validation scheme is proposed that enables the locality-aware private cache replication scheme to be implementable in processors with out-of-order memory that employ popular memory consistency models. This method does not rely on cache coherence messages to detect speculation violations, and hence is applicable to the locality-aware protocol. The timestamp mechanism is efficient due to the observation that consistency violations only occur due to conflicting accesses that have temporal proximity (i.e., within a few cycles of each other), thus requiring timestamps to be stored only for a small time window. Fourth, a locality-aware last-level cache (LLC) replication scheme that better manages the LLC is proposed. This scheme adapts replication at runtime based on fine-grained cache line reuse information and thereby, balances data locality and off-chip miss rate for optimized execution. Finally, all the above schemes are combined to obtain a cache hierarchy replication scheme that provides optimal data locality and miss rates at all levels of the cache hierarchy. The design of this scheme is motivated by the experimental observation that both locality-aware private cache & LLC replication enable varying performance improvements across benchmarks. These techniques enable optimal use of the on-chip cache capacity, and provide low-latency, low-energy memory access, while retaining the convenience of shared memory and preserving the same memory consistency model. On a 64-core multicore processor with out-of-order cores, Locality-aware Cache Hierarchy Replication improves completion time by 15% and energy by 22% over a state-of-the-art baseline while incurring a storage overhead of 30.7 KB per core. (i.e., 10% the aggregate cache capacity of each core).

Download or read book A Primer on Memory Consistency and Cache Coherence written by Daniel J. Sorin and published by Morgan & Claypool Publishers. This book was released on 2011 with total page 215 pages. Available in PDF, EPUB and Kindle. Book excerpt: Many modern computer systems and most multicore chips (chip multiprocessors) support shared memory in hardware. In a shared memory system, each of the processor cores may read and write to a single shared address space. For a shared memory machine, the memory consistency model defines the architecturally visible behavior of its memory system. Consistency definitions provide rules about loads and stores (or memory reads and writes) and how they act upon memory. As part of supporting a memory consistency model, many machines also provide cache coherence protocols that ensure that multiple cached copies of data are kept up-to-date. The goal of this primer is to provide readers with a basic understanding of consistency and coherence. This understanding includes both the issues that must be solved as well as a variety of solutions. We present both highlevel concepts as well as specific, concrete examples from real-world systems. Table of Contents: Preface / Introduction to Consistency and Coherence / Coherence Basics / Memory Consistency Motivation and Sequential Consistency / Total Store Order and the x86 Memory Model / Relaxed Memory Consistency / Coherence Protocols / Snooping Coherence Protocols / Directory Coherence Protocols / Advanced Topics in Coherence / Author Biographies

Download or read book Cache Coherence Techniques for Multicore Processors written by Michael R. Marty and published by . This book was released on 2008 with total page 232 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Efficient and Scalable Cache Coherence for Chip Multiprocessors written by Alberto Ros and published by LAP Lambert Academic Publishing. This book was released on 2010-02 with total page 196 pages. Available in PDF, EPUB and Kindle. Book excerpt: Chip multiprocessors (CMPs) constitute the new trend for increasing the performance of future computers. In the near future, chips with tens of cores will become more popular. Nowadays, directory-based protocols constitute the best alternative to keep cache coherence in large-scale systems. Nevertheless, directory-based protocols have two important issues that prevent them from achieving better scalability: the directory memory overhead and the long cache miss latencies. This book focuses on these key issues. The first proposal is a scalable distributed directory organization that copes with the memory overhead of directory-based protocols. The second proposal presents the direct coherence protocols, which are aimed at avoiding the indirection problem of traditional directory-based protocols and, therefore, they improve applications' performance. Finally, a novel mapping policy for distributed caches is presented. This policy reduces the long access latency while lessening the number of off-chip accesses, leading to improvements in applications' execution time.

Download or read book Proceedings of the 1993 International Conference on Parallel Processing written by C.Y. Roger Chen and published by CRC Press. This book was released on 1993-08-16 with total page 392 pages. Available in PDF, EPUB and Kindle. Book excerpt: This three-volume work presents a compendium of current and seminal papers on parallel/distributed processing offered at the 22nd International Conference on Parallel Processing, held August 16-20, 1993 in Chicago, Illinois. Topics include processor architectures; mapping algorithms to parallel systems, performance evaluations; fault diagnosis, recovery, and tolerance; cube networks; portable software; synchronization; compilers; hypercube computing; and image processing and graphics. Computer professionals in parallel processing, distributed systems, and software engineering will find this book essential to their complete computer reference library.

Download or read book Scalable Shared Memory Multiprocessing written by Daniel E. Lenoski and published by Elsevier. This book was released on 2014-06-28 with total page 364 pages. Available in PDF, EPUB and Kindle. Book excerpt: Dr. Lenoski and Dr. Weber have experience with leading-edge research and practical issues involved in implementing large-scale parallel systems. They were key contributors to the architecture and design of the DASH multiprocessor. Currently, they are involved with commercializing scalable shared-memory technology.

Download or read book Towards Scalable Write update Cache Coherence Protocols written by Alain Raynaud and published by . This book was released on 1995 with total page 66 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book SOFTWARE SHARED VIRTUAL MEMORY written by Chit-Ho Dominic Hung and published by Open Dissertation Press. This book was released on 2017-01-26 with total page 174 pages. Available in PDF, EPUB and Kindle. Book excerpt: This dissertation, "A Software Shared Virtual Memory System With Three Way Coherence Protocols on the Intel Single-chip Cloud Computer" by Chit-ho, Dominic, Hung, 熊哲皓, was obtained from The University of Hong Kong (Pokfulam, Hong Kong) and is being sold pursuant to Creative Commons: Attribution 3.0 Hong Kong License. The content of this dissertation has not been altered in any way. We have altered the formatting in order to facilitate the ease of printing and reading of the dissertation. All rights not granted by the above license are retained by the author. Abstract: With the advancement of design and fabrication of high-performance integrated circuits technology, it is foreseeable that processors with more than 1,000 cores per die will appear in the near future. However, these many-core architectures have introduced a lot of challenges at the memory system level, such as complicated cache coherence and limited memory access speed, to name a few. This thesis focuses on one prominent many-core prototype - the Intel's Single-chip Cloud Computer (SCC). The SCC architecture does not provide hardware cache coherency. Instead, it relies on on-chip programmable memory. The baseline coherence protocol for the SCC is the Software Managed Coherence (SMC) layer. To achieve memory consistency, it accesses shared memory without part of the typical cache hierarchy for efficient invalidation and flushing. We found that performance provided by this coherence layer in this manner is sub-optimal because accesses of shared memory would all turn into data update messages within the network mesh. As cache locality could not be exploited to its full potential, the execution pipelines stall much often for memory fetches from outside the chip. This research is to address the performance problem of shared virtual memory consistency for this cache in-coherent architecture. Oriented at sitting data on-chip as much as possible to reduce memory accesses external to the chip, we propose two techniques to leverage the cache hierarchy to full and reside data in the on-chip scratchpad memory. First, targeted at the architectural specificity of the hardware, we redesigned traditional software distributed shared memory (SDSM) to allow shared data be treated transparently like private memory so the cache hierarchy can be fully utilised without sacrificing memory consistency. Second, we propose a distance-aware page allocation scheme that samples access frequencies and select the most frequently-recently used pages to be stored on the on-chip scratchpad memory. Our experimental results show that our first technique, the ordinary SDSM outperforms the current SMC approach by 5 times. Moreover, in some cases, with the second technique that is based on scratchpad memory, our proposed system outperforms further by an additional 1.57 times. Our experiments also demonstrated that the SMC approach is not scalable due to congestion of the network mesh by coherence traffic generated while the two new approaches continued to scale well. The main contribution of this research is the implementation of a cache coherence software library system built for an architecture that comes with non-coherent cache hardware and just relies on software-defined cache. This new cache hierarchy has evidently opened the door for smarter and faster inter-processor-core data sharing without the need of complicated cache coherence hardware. Subjects: Distributed shared memory Cloud computing