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Title: Contention Modeling for Multithreaded Distributed Shared Memory Machines: The Cray XMT

Abstract

Distributed Shared Memory (DSM) machines are a wide class of multi-processor computing systems where a large virtually-shared address space is mapped on a network of physically distributed memories. High memory latency and network contention are two of the main factors that limit performance scaling of such architectures. Modern high-performance computing DSM systems have evolved toward exploitation of massive hardware multi-threading and fine-grained memory hashing to tolerate irregular latencies, avoid network hot-spots and enable high scaling. In order to model the performance of such large-scale machines, parallel simulation has been proved to be a promising approach to achieve good accuracy in reasonable times. One of the most critical factors in solving the simulation speed-accuracy trade-off is network modeling. The Cray XMT is a massively multi-threaded supercomputing architecture that belongs to the DSM class, since it implements a globally-shared address space abstraction on top of a physically distributed memory substrate. In this paper, we discuss the development of a contention-aware network model intended to be integrated in a full-system XMT simulator. We start by measuring the effects of network contention in a 128-processor XMT machine and then investigate the trade-off that exists between simulation accuracy and speed, by comparing three network modelsmore » which operate at different levels of accuracy. The comparison and model validation is performed by executing a string-matching algorithm on the full-system simulator and on the XMT, using three datasets that generate noticeably different contention patterns.« less

Authors:
; ;
Publication Date:
Research Org.:
Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
1023734
Report Number(s):
PNNL-SA-76834
400470000; TRN: US201120%%1070
DOE Contract Number:  
AC05-76RL01830
Resource Type:
Conference
Resource Relation:
Conference: 11th IEEE/ACM International Symposium on Cluster, Cloud and Grid Computing (CCGrid 2011), May 23-26, 2011, Newport Beach, California, 275-284
Country of Publication:
United States
Language:
English
Subject:
99 GENERAL AND MISCELLANEOUS//MATHEMATICS, COMPUTING, AND INFORMATION SCIENCE; ACCURACY; ALGORITHMS; COMPUTER ARCHITECTURE; CRAY COMPUTERS; PERFORMANCE; SCALING LAWS; SIMULATION; SIMULATORS; SUPERCOMPUTERS; VALIDATION; Cray XMt, contention, network modeling, simulation, multithreading

Citation Formats

Secchi, Simone, Tumeo, Antonino, and Villa, Oreste. Contention Modeling for Multithreaded Distributed Shared Memory Machines: The Cray XMT. United States: N. p., 2011. Web. doi:10.1109/CCGrid.2011.39.
Secchi, Simone, Tumeo, Antonino, & Villa, Oreste. Contention Modeling for Multithreaded Distributed Shared Memory Machines: The Cray XMT. United States. doi:10.1109/CCGrid.2011.39.
Secchi, Simone, Tumeo, Antonino, and Villa, Oreste. Wed . "Contention Modeling for Multithreaded Distributed Shared Memory Machines: The Cray XMT". United States. doi:10.1109/CCGrid.2011.39.
@article{osti_1023734,
title = {Contention Modeling for Multithreaded Distributed Shared Memory Machines: The Cray XMT},
author = {Secchi, Simone and Tumeo, Antonino and Villa, Oreste},
abstractNote = {Distributed Shared Memory (DSM) machines are a wide class of multi-processor computing systems where a large virtually-shared address space is mapped on a network of physically distributed memories. High memory latency and network contention are two of the main factors that limit performance scaling of such architectures. Modern high-performance computing DSM systems have evolved toward exploitation of massive hardware multi-threading and fine-grained memory hashing to tolerate irregular latencies, avoid network hot-spots and enable high scaling. In order to model the performance of such large-scale machines, parallel simulation has been proved to be a promising approach to achieve good accuracy in reasonable times. One of the most critical factors in solving the simulation speed-accuracy trade-off is network modeling. The Cray XMT is a massively multi-threaded supercomputing architecture that belongs to the DSM class, since it implements a globally-shared address space abstraction on top of a physically distributed memory substrate. In this paper, we discuss the development of a contention-aware network model intended to be integrated in a full-system XMT simulator. We start by measuring the effects of network contention in a 128-processor XMT machine and then investigate the trade-off that exists between simulation accuracy and speed, by comparing three network models which operate at different levels of accuracy. The comparison and model validation is performed by executing a string-matching algorithm on the full-system simulator and on the XMT, using three datasets that generate noticeably different contention patterns.},
doi = {10.1109/CCGrid.2011.39},
journal = {},
number = ,
volume = ,
place = {United States},
year = {2011},
month = {7}
}

Conference:
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