Implementation of cache coherence protocol for COMA multiprocessor systems based on the scalable coherent interface

2004 ◽  
Vol 27 (1) ◽  
pp. 71-88
Author(s):  
M. AL-Rousan ◽  
S. Ahmed
Author(s):  
M. AL-ROUSAN ◽  
O. AL-JARRAH ◽  
M. MOWAFI

Recently, connecting thousands of processors via interconnection networks based on multiple (hierarchical) rings has an increased interest. This is due to the large acceptance and success of the Scalable Coherent Interface (SCI) technology. The inherently weak behavior of ring architecture has led interconnection designers to consider various choices to improve the overall network reliability. An interesting choice is to use braided rings instead of the single (basic) rings in the hierarchy. In this paper, we present new formulas for computing K-processor reliability of SCI ring-based hierarchical networks in the context of large-scale multiprocessor systems. The derived formulas are general and applicable to any given systems size consisting of an arbitrary number of levels. The reliability of hierarchical systems based on the basic and braided rings is evaluated and analyzed using the derived formulas. The results show that hierarchical systems based on braided rings significantly improve the reliability of hierarchies constructed of basic rings. The results are general and not limited to systems of SCI rings; the analysis is valid for any type of rings architecture such as token and slotted rings.


Author(s):  
Qiang Li

Abstract Multimedia technology has become widely available and it has tremendous potential. As computers getting faster every day, multimedia applications are reaching new ground constantly. However, a fundamental problem of multimedia systems is the interprocessor/intermachine communication speed. In this paper, we introduce a platform based on the Scalable Coherent Interface (SCI, ANSI/IEEE std 1596). The system can be physically distributed but logically closely coupled. All processors/machines in an SCI system shared physical memory and cache coherence is maintained even among remote processors. The interprocessor communication bandwidth can be as high as 1 Gbyte/sec. We will discuss the features of SCI-based systems when multimedia application is considered.


2018 ◽  
pp. 47-53
Author(s):  
B. Z. Shmeylin ◽  
E. A. Alekseeva

In this paper the tasks of managing the directory in coherence maintenance systems in multiprocessor systems with a large number of processors are solved. In microprocessor systems with a large number of processors (MSLP) the problem of maintaining the coherence of processor caches is significantly complicated. This is due to increased traffic on the memory buses and increased complexity of interprocessor communications. This problem is solved in various ways. In this paper, we propose the use of Bloom filters used to accelerate the determination of an element’s belonging to a certain array. In this article, such filters are used to establish the fact that the processor belongs to some subset of the processors and determine if the processor has a cache line in the set. In the paper, the processes of writing and reading information in the data shared between processors are discussed in detail, as well as the process of data replacement from private caches. The article also shows how the addresses of cache lines and processor numbers are removed from the Bloom filters. The system proposed in this paper allows significantly speeding up the implementation of operations to maintain cache coherence in the MSLP as compared to conventional systems. In terms of performance and additional hardware and software costs, the proposed system is not inferior to the most efficient of similar systems, but on some applications and significantly exceeds them.


Author(s):  
M. Daoui ◽  
M. Lalam ◽  
B. Djamah ◽  
A. Bilami

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