This website uses cookies to ensure you have the best experience. Learn more

Swel: Hardware Cache Coherence Protocols Essay

1906 words - 8 pages

[Type the company name] |
REPORT |
SWEL: Hardware Cache Coherence Protocols to Map Shared Data onto Shared Caches |
|
Asadullah |
12/15/2013 |

… |

Contents
Abstract 3
Introduction 3
Proposed Solution (SWEL) 5
Optimizations of SWEL 6
Dynamically Tuned RSWEL 7
Implementation 7
Experiment and Results 7
Conclusion 10
References 10

Abstract
Shared Memory Multi processors require cache coherence in order to keep cached values updated while performing operations. Snooping and directory based protocols are two well known standards of cache coherence. However both of them possess some problems. Snooping protocol is not scalable and is only suitable for systems ...view middle of the document...

The bus in SMP is therefore replaced with scalable network. Snooping protocol shows poor performance in network based SMP. Whenever a write operation is performed by any processor, a snoop is sent to all caches to invalidate or update the shared block of data. This can increase communication overhead when there are too many sharers. This problem was resolved in directory based protocol. In this protocol every cache looks up the directory of blocks with status bits. Status bits keep track of all sharers and their corresponding status of block. Snoop is sent only when a shared block is required for read. This outperforms the drawback of snooping protocol. However directory based protocol has some disadvantages. Those disadvantages are:
i. Directory storage
Each block in L2 cache maintains a directory of sharers. For each sharer a bit is reserved in the block hence the storage increases linearly with number of sharers.
ii. Indirection
Multiple messages are exchanged through network before the coherence operation is deemed to complete. For example, when a processor performs write, the directory first sends invalidation to the sharers and the write operations is only performed after acknowledgement is received from all sharers.
iii. Complexity
Directory-based coherence conventions are frequently error-inclined and whole research communities are handling their efficient outline with formal verication.
Many of the applications running on today's multi-core machines are still single-threaded applications that do not explicitly rely on cache coherence. Further, future many-cores in servers and datacenters will likely execute multiple VMs (each possibly executing a multi-programmed workload), with no data sharing between VMs, again removing the need for cache coherence.
Moreover, several machines share data through message passing hence no cache coherence protocol is needed.
Figure 1 indicates that very little data is actually shared by two or more cores; on average 77.0% of all memory locations are touched by only a single processor.

Based on above arguments, we claim that the percentage of processing required for shared memory multi-threaded execution that actually needs cache coherence will be much less than that utilized by traditional hardware cache coherent multiprocessors.
Proposed Solution (SWEL)
The proposed solution is based on the premise that most blocks are either private to a core or read-only, and hence, do not require coherence. The basic claim is this: (i) many blocks do not need coherence and can be freely placed in L1 caches; (ii) blocks that would need coherence if placed in L1 are only placed in L2. Given this claim, it appears that the coherence protocol is all but eliminated.
This is only partially true as other book-keeping is now required to identify which of the above two categories a block falls into. If a cache block is either private or is read-only, then that block can be safely...

Other Papers Like Swel: Hardware Cache Coherence Protocols

Implementation And Evaluation Of Wireless Mesh Networks On Manet Routing Protocols

4352 words - 18 pages another type of ad hoc networking, WMNs diversify and enhance the capabilities of ad hoc networks. The devices like laptops, mobile phones, wireless mouse, wireless keyboards, PDA etc come under the category of mesh clients. Even though mesh clients can also work as a router, the hardware platform and software for them can be made simpler than those for mesh routers. For instance, communication protocols for mesh clients can be light-weight, as

Improving Byzantine Fault Tolerance Using Concurrent Information

2744 words - 11 pages classical epistemologies at the time [4]. The choice of spreadsheets in [5] differs from ours in that we visualize only extensive information in our method. As a result, comparisons to this work are fair. Instead of architecting the practical unification of e-commerce and cache coherence [6], we address this challenge simply by improving checksums. Obviously, comparisons to this work are astute. Anderson and Thompson suggested a scheme for

Packet Sniffer Report

8200 words - 33 pages Swarna Swaminathan (0131CS081077) (0131CS081084) CONTENTS DECLARATION … ii CERTIFICATE … iii ACKNOWLEDGEMENT … iv LIST OF FIGURES … vi 1. INTRODUCTION ... 01 2. REVIEW OF LITERATURE … 06 2.1 TCP/IP Protocols … 06 2.2 IP Addressing … 09 2.3 Internet Routing … 12 2.4 IP Routing … 12 2.5 Transmission Control Protocol

Capstone Budget Nt2799

3567 words - 15 pages Licenses (Maximum) | 1 (5) | Encryption/Authentication | Key Exchange | Route-Based VPN | Networking | TZ 105/W | IP Address Assignment | NAT Modes | Routing Protocols | QoS | Authentication | SSO | AD, eDirectory, RADIUS Accounting, NTLM, X-Forwarders | VoIP | Standards | RADIUS, IEEE 802.3 | Certifications Pending | Common Access Card (CAC) | Hardware | TZ 105/W | Form Factor | Power Supply (W) | 18W

Cluster Computing

5334 words - 22 pages without sacrificing performance or data integrity. Each node can concurrently cache shared data in local processor memory through hardware-assisted cluster-wide serialization and coherency controls. As a result, work requests that are associated with a single workload, such as business transactions or database queries, can be dynamically distributed for parallel execution on nodes in the sysplex cluster based on available processor capacity

Cmu 213 Ppt

2318 words - 10 pages are distant in both time and space  Memory performance is not uniform  Cache and virtual memory effects can greatly affect program performance  Adapting program to characteristics of memory system can lead to major speed improvements 8 Carnegie Mellon Memory Referencing Bug Example double fun(int i) { volatile double d[1] = {3.14}; volatile long int a[2]; a[i] = 1073741824; /* Possibly out of bounds */ return d[0]; } fun(0

Operating System Analysis Paper

4124 words - 17 pages , hibernation, and dump files. Installation and Activation is quite different than that of Windows XP. Any version of Windows Server 2008 can be evaluated without a product key. However, failing to activate within ten days will cause the system to shut down every hour due to the licensing service (Microsoft, 2010). Linux The system requirements for Red Hat Linux are very light. These are the minimum hardware requirements and they may be enough to

Cis 210 – Systems Analysis and Development Website Migration Term Paper

3905 words - 16 pages of the inventory. | Figure 6A is show the sample main page webpage screen shot. Figure 6B is show the sample online purchase page screen shot. Essential Support Operations Required for Internally Hosted Website Incessant maintenance of the server hardware, and the back-up protocols of the server. Routine updation of the software and hardware components for keeping up with the latest standards of technology. Along, with the

Kudler Fine Foods Frequent Shopper Program

4157 words - 17 pages Cycle (SDLS) for the program can be found later in the report and will delve deeper into the details of the SDLC. Kudler Fine Foods Top Known Threats Table Area of System | Threats | Potential Vulnerability (weakness) | Hardware | Hardware failure or Lack of hardware | Lack of security weaknesses in protocols and procedures. Ensure that all security options are explored on items like firewall and router as well as networking

Unix Vs. Windows Server

2110 words - 9 pages virtual memory, and the physical memory. Physical memory being the space found on the computer's hardware. The virtual memory is disk room, which is usually set to the side to supply additional cache for system and user's applications. Usually, these two types of memory are used together. Linux uses something called a "swap" space (Linux.com, 2012). Swap space is a method in which a page of memory is copied on the hard disk, to free up that page of

Exploring the Transistor and Thin Clients with Musrolquinine

2400 words - 10 pages file systems," in Proceedings of OOPSLA, May 1990. [11] R. T. Morrison, F. Garcia, and R. Reddy, "Simulating e-commerce and cache coherence," in Proceedings of the Workshop on Random, Secure Technology, Feb. 2003. [12] C. I. Jones, "Interactive, cooperative epistemologies for evolutionary programming," in Proceedings of VLDB, June 1999. [13] J. Ullman, "A methodology for the development of Scheme," Journal of Reliable Modalities, vol. 59

Related Essays

Dynamic Source Routing Essay

1857 words - 8 pages , where the Route Discovery mechanism handles establishment of routes and the Route Maintenance mechanism keeps route information updated. Assumptions Some assumptions concerning the behavior of the nodes that participate in the ad hoc network are made. The most important assumptions are the following: A1. All nodes that participate in the network are willing to participate fully in the protocols of the network. A2. The diameter of an ad hoc

Internet Banking Essay

1639 words - 7 pages connection through a service provider Browsers: Internet Explorer 5.0 and above, Netscape Navigator Getting slow response when I am accessing the Allahabad Bank Internet Banking. Why? o You are not using the recommended browser, operating system and hardware. o Your Internet Service Provider, Local Area Network may be facing sporadic slowness. Top How can I clear my browser cache? Internet Explorer Go to “Tools” Go to “Internet Options

An Extensive Unification Of Massive Multiplayer Online Role Playing Games And 802.11b

1727 words - 7 pages answer many of the issues faced by today’s analysts [2]. To achieve this ambition for DNS, we explored an analysis of RPCs [13, 21, 31, 36, 3, 19, 46]. Furthermore, we validated not only that the seminal psychoacoustic algorithm for the development of link-level acknowledgements by N. Kumar et al. [9] runs in O(log n) time, but that the same is true for cache coherence. We see no reason not to use 5 0 0.01 0.02 0.03 0.04 0.05 0.06 0.07 0.08 0.09 0.1 2 4 6 8 10 12 14 16 18 power (dB) complexity (# CPUs) Figure 6: The 10th-percentile response time of our method, compared with the other systems. our methodology for analyzing the analysis of DNS.

Computer Project Essay

2048 words - 9 pages Intel Dual Core processor with a speed of 3 GHz. It has a 6 GB RAM memory and 4 MB of cache memory. Therefore, these specs show that this laptop is good enough to run multiple (but not too many) programs simultaneously without lagging and perform fast. Furthermore, it has a hard drive disk space of 1 TB, which is sufficient to run the Windows 10 operating system, the software I am interested in (which will be discussed later in the “Software