Title
On The Performance And Technological Impact Of Adding Memory Controllers In Multi-Core Processors
Abstract
The increasing core-count on current and future processors is posing critical challenges to the memory subsystem to efficiently handle concurrent memory requests. The current trend is to increase the number of memory channels available to the processor's memory controller. In this paper we investigate the advantages and disadvantages of this approach from both a technological and an application performance viewpoint. In particular, we explore the trade-off between employing multiple memory channels per memory controller and the use of multiple memory controllers with fewer memory channels. Experiments conducted on two current state-of-the-art multi-core processors, a 6-core AMD Istanbul and a 4-core Intel Nehalem-EP, using the STREAM benchmark and a wide range of production applications. An analytical model of the STREAM performance is used to illustrate the diminishing return obtained when increasing the number of memory channels per memory controller whose effect is also seen in the application performance. In addition, we show that this performance degradation can be efficiently addressed by increasing the ratio of memory controllers to channels while keeping the number of memory channels constant. Significant performance improvements can be achieved in this scheme, up to 28%, in the case of using two memory controllers each with one channel compared with one controller with two memory channels.
Year
DOI
Venue
2010
10.1142/S0129626410000284
PARALLEL PROCESSING LETTERS
Keywords
Field
DocType
Memory channels, Memory controllers, Multi-core processors, Memory bandwidth, Performance evaluation, Scientific applications
Registered memory,Interleaved memory,Semiconductor memory,Extended memory,Computer science,Parallel computing,Memory management,Flat memory model,Memory controller,Embedded system,Memory refresh
Journal
Volume
Issue
ISSN
20
4
0129-6264
Citations 
PageRank 
References 
0
0.34
2
Authors
3
Name
Order
Citations
PageRank
José Carlos Sancho138229.97
Darren J. Kerbyson21102104.36
Michael Lang326619.91