Efficient Strategies for Software-Only Directory Protocols in Shared-Memory Multiprocessors

Document type: Conference Papers
Peer reviewed: Yes
Author(s): Håkan Grahn, Per Stenström
Title: Efficient Strategies for Software-Only Directory Protocols in Shared-Memory Multiprocessors
Conference name: 22nd Annual International Symposium on Computer Architecture
Year: 1995
Pagination: 38-47
ISBN: 0-89791-698-0 (hft.) 0-7803-3000-5 (inb.) 0-7803-3001-3 (mikrofiche)
Publisher: IEEE Computer Society Press
City: Santa Margherita Ligure; Italy
Organization: Blekinge Institute of Technology
Department: Dept. of Computer Science and Business Administration (Institutionen för datavetenskap och ekonomi)
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+46 455 780 00
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Authors e-mail: hakan.grahn@ide.hk-r.se
Language: English
Abstract: The cost, complexity, and inflexibility of hardware-based directory protocols motivate us to study the performance implications of protocols that emulate directory management using software handlers executed on the compute processors. An important performance limitation of such software-only protocols is that software latency associated with directory management ends up on the critical memory access path for read miss transactions. We propose five strategies that support efficient data transfers in hardware whereas directory management is handled at a slower pace in the background by software handlers. Simulations show that this approach can remove the directory-management latency from the memory access path. Whereas the directory is managed in software, the hardware mechanisms must access the memory state in order to enable data transfers at a high speed. Overall, our strategies reach between 60% and 86% of the hardware-based protocol performance.
Subject: Computer Science\Computersystems
Keywords: Network protocols; Distributed computer systems; Computational complexity; Data handling; Critical path analysis; Computer software; Data transfer; Buffer storage; Program processors