ネットワークコンピューティング論Ⅱ
平成27年度 後期
火曜 第２時限（１０：４０－１２：１０）
吉永 努（ＵＥＣ)
yosinaga@is.uec.ac.jp
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1
内容
• 分散・並列処理計算機における相互結合ネット
ワークとその上でのメッセージ・ルーティング技
法などについて学ぶ
• 資料
http://comp.is.uec.ac.jp/yoshinagalab/yoshinaga/dp2.html
• http://www.gap.upv.es/slides/appendixE.html
• http://booksite.mkp.com/9780123838728/references.php
appendix_f.pdf (P.118, 2MB)
• TA: 村田 篤志 amurata@comp.is.uec.ac.jp
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References
• T. M. Pinkston and J. Duato: Interconnection
Networks, Appendix E in Computer Architecture:
A Quantitative Approach, 4th Edition, Morgan
Kaufmann publishers (2006).
• 5th Edition, Morgan Kaufmann publishers (2011).
• J. Duato, S. Yalamanchili, L. Ni: Interconnection
Networks - an Engineering Approach-, 第2版,
Morgan Kaufmann publishers (2003)
• 富田眞治： 並列コンピュータ、昭晃堂（1996）
• W.D. Dally, B. Towles: Principles and Practices
of Interconnection Networks,
Morgan Kaufmann publishers (2003)
3
What is an interconnection
Network?
• It is a programmable system that transports data
between terminals, such as processors and
memory.
• It is programmable in the sense that it makes
different connections at different points.
• It is a system because it is composed of many
components: buffers, channels, switches, and
controls that works together to deliver data.
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Interconnection Network (1/2)
Interconnection Network
P
P
P
M
M
M
Multicomputer
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Interconnection Network (2/2)
P
P
P
Interconnection Network
M
M
M
UMA type shared memory multiprocessor
It is also called dance-hall architecture.
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Trend
• Its performance is increasing with processor
performance at a rate of 50% per year.
• Communication is a limiting factor in the
performance of many modern systems.
• Buses have been unable to keep up with the
bandwidth demand, and point-to-point
interconnection networks are rapidly taking
over.
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7
Computer Classifications (%)
2015/06
2014/06
2013/06
MPP
13.2
14.6
16.6
Cluster
86.8
85.4
83.4
Others
0.0
0.0
0.0
http://www.top500.org/
share of the TOP500 June, 2015 – June, 2013
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Examples of clusters
Processors
Tianhe-2
(天河2号）
China
2013
Tsubame 2.5
Tokyo Tech.
2013
Accelerator Interconnect
Intel Xeon
E5-2692 12C
2.2 GHz×2
×16K
Xeon Phi
31S1P (57
cores)×3
×16K
TH Express-2
(proprietary)
Fat tree
Xeon X5670
2.93GHz×2
×1,408
NVIDIA
Kepler K20x
×3×1,048
Infiniband
QDR
(40Gbps) ×2
Fat tree
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Examples of MPPs
K computer
@RIKEN
Fujitsu
2011
Titan@ORNL
Cray XK7
2012
Node
Topology
#core
Rmax
SPARC64 VIIIfx
2 GHz
(16 GFlops×
8 cores)
6D mesh/
3D torus
Tofu interconnect
80K-node x 8-core
= 640K-core
10.51 PFlops
7,890 KW
3D torus
Gemini
interconnect
18,688 nodes
(200 Cabinets)
27.11 PFlops
8,209 KW
AMD Opteron
16C 2.2 GHz
+ NVIDIA K20x
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Other Networks of Supercomputers
• Sequoia/BG Q (2011): 5D torus, proprietary IBM
SeaStar
• Pleiades / NASA (2011): partial 11D hypercube
topology with IB QDR/DDR
• Red Sky/ Sandia National Lab. (2010):
3D torus (12 bristled node) with IB QDR switches
• IBM Roadrunner (2009): fat-tree with IB DDR
• Earth Simulator2 / NEC SX-9E (2009):
Fat-Tree (64GB/s/cpu, 8-CPU/node, 160 nodes)
• IBM Blue Gene/L (2004): 3D torus proprietary
(64 x 32 x 32 = 64K nodes)
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Architecture vs. software
memory
programming
UMA
(SMP)
shared
OpenMP
NUMA
(MPP)
distributed
(not shared)
MPI
(Message Passing Interface)
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Network Design (1/3)
• Performance: latency and throughput
(bandwidth)
• Scalability: #processors vs. network,
memory, I/O bandwidth
• Incremental expandability:
small to maximum size
• Partitionability: netwrok may be partitioned
for several users
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Network Design (2/3)
• Simplicity: simple design, higher clock
frequency, easy to use
• Distance span: smaller system is preferred
for noise and cable delay, etc.
• Physical constraints: packaging (pin count),
wiring(wire length), and maintenance
(power consumption) should meet physical
limitation.
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Network Design (3/3)
• Reliability: fault tolerant, reliable
communication, hot swap
• Expected workload: robust performance
over a wade range of traffic conditions.
• Cost: trade-offs between cost and
performance.
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Classifiction of Interconnection Networks
• Shared-Medium Networks
– Local area networks (ethernet, token ring)
– Backplane bus (e.g. SUN Gigaplane)
• Direct Networks (router-based)
– mesh, torus, hypercube, tree, … etc.
• Indirect Networks (switch-based)
• Hybrid Networks
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Shared-Medium Networks
(LAN)
• Arbitration that determines the mastership of the
shared-medium network to resolve network access
is needed.
• The most well-known protocol is carrier-sense
multiple access with collision detection
(CSMA/CD).
• Token bus and token ring pass a token from the
owner which has the right to access the bus/ring
and resolve nondeterministic waiting time.
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Shared-Medium Networks (Backplane bus)
• It is commonly used to interconnect processor(s)
and memory modules to provide SMP
(Symmetrical Memory Processor) architecture.
• It is realized by printed lines on a circuit board by
discrete wiring.
• Gigaplane in SUN Enterprise x000 server(1996):
2.6GB/s, 256 bits data, 42 bits address, 83.8MHz
clock.
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Direct (static) Networks
• Consists of a set of nodes.
• Each node is directly connected to a subset
of other nodes in the network.
• Examples:
– 2D mesh (intel Paragon), 3D mesh (MIT J-Mahine)
– 2D torus (Fujitsu AP3000), 3D torus (Cray T3D, T3E)
– Hypercube (CM1, CM2, nCUBE)
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Mesh topology
node
2D
3D
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Torus topology
2D
3D
(4-ary 2-cube)
(3-ary 3-cube)
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Hypercube (binary n-cube)
4D
(2-ary 4-cube)
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tree
Binary tree
fat tree
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x tree
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Hierarchical topology (1/2)
Pyramid
Hierarchical ring
(Hierarchical 2D mesh)
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Hierarchical topology (2/2)
Cube-connected cycles
RDT
(Recursive Diagonal Torus)
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Hypermesh
(spaninng-bus hypercube)
Single or
multiple buses
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Base-m n-cube (hyper-crossbar)
770
070
777
077
707
000
007
8x8 crossbar
Base-8 3-cube (Toshiba Prodigy)
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Diameter and degrees (1/2)
2D
mesh
#node
N
2D
torus
Ｎ
Diameter
２√N
√N
degree
４
４
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3D
torus
Ｎ
binary
n-cube
Ｎ = 2n
√N
log N
６
log N
３
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Diameter and degrees (2/2)
Base-m
n-cube
#node
N = mn Ｎ = n2n
Diameter logm N
degree
CCC
logm N
3n/2
3
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Binary
tree
Ｎ
ring
2log N
N/2
3
2
３
Ｎ
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