Title
Managing Data Placement in Memory Systems with Multiple Memory Controllers.
Abstract
Modern processors such as Tilera’s Tile64, Intel’s Nehalem, and AMD’s Opteron are migrating memory controllers (MCs) on-chip, while maintaining a large, flat memory address space. This trend to utilize multiple MCs will likely continue and a core or socket will consequently need to route memory requests to the appropriate MC via an inter- or intra-socket interconnect fabric similar to AMD’s HyperTransportTM, or Intel’s Quick-Path InterconnectTM. Such systems are therefore subject to non-uniform memory access (NUMA) latencies because of the time spent traveling to remote MCs. Each MC will act as the gateway to a particular region of the physical memory. Data placement will therefore become increasingly critical in minimizing memory access latencies. Increased competition for memory resources will also increase the memory access latency variation in future systems. Proper allocation of workload data to the appropriate MC will be important in decreasing the variation and average latency when servicing memory requests. The allocation strategy will need to be aware of queuing delays, on-chip latencies, and row-buffer hit-rates for each MC. In this paper, we propose dynamic mechanisms that take these factors into account when placing data in appropriate slices of physical memory. We introduce adaptive first-touch page placement, and dynamic page-migration mechanisms to reduce DRAM access delays for multi-MC systems. We also introduce policies that can handle data placement in memory systems that have regions with heterogeneous properties. The proposed policies yield average performance improvements of 6.5% for adaptive first-touch page-placement, and 8.9% for a dynamic page-migration policy for a system with homogeneous DRAM DIMMs. We also show improvements in systems that contain DIMMs with different performance characteristics.
Year
DOI
Venue
2012
10.1007/s10766-011-0178-1
International Journal of Parallel Programming
Keywords
Field
DocType
DRAM, Phase change memory, Data locality, Heterogeneous memory hierarchies
Registered memory,Interleaved memory,Uniform memory access,Physical address,Computer science,Parallel computing,Memory management,Non-uniform memory access,Memory map,Flat memory model
Journal
Volume
Issue
ISSN
40
1
1573-7640
Citations 
PageRank 
References 
2
0.36
37
Authors
5
Name
Order
Citations
PageRank
Manu Awasthi12159.57
David W. Nellans226412.33
Kshitij Sudan31908.71
Rajeev Balasubramonian42302116.79
Al Davis598654.47