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Designing Cloud and Grid Computing Systems
with InfiniBand and High-Speed Ethernet
Dhabaleswar K. (DK) Panda
The Ohio State University
E-mail: [email protected]
http://www.cse.ohio-state.edu/~panda
A Tutorial at CCGrid 11
by
Sayantan Sur
The Ohio State University
E-mail: [email protected]
http://www.cse.ohio-state.edu/~surs
http://www.cse.ohio-state.edu/~pandahttp://www.cse.ohio-state.edu/~surshttp://www.cse.ohio-state.edu/~surshttp://www.cse.ohio-state.edu/~surshttp://www.cse.ohio-state.edu/~surshttp://www.cse.ohio-state.edu/~pandahttp://www.cse.ohio-state.edu/~pandahttp://www.cse.ohio-state.edu/~panda8/21/2019 Ccgrid11 Ib Hse Last
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Introduction
Why InfiniBand and High-speed Ethernet?
Overview of IB, HSE, their Convergence and Features
IB and HSE HW/SW Products and Installations
Sample Case Studies and Performance Numbers
Conclusions and Final Q&A
CCGrid '11
Presentation Overview
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CCGrid '11
Current and Next Generation Applications and
Computing Systems
3
Diverse Range of Applications
Processing and dataset characteristics vary
Growth of High Performance Computing
Growth in processor performance
Chip density doubles every 18 months
Growth in commodity networking
Increase in speed/features + reducing cost
Different Kinds of Systems
Clusters, Grid, Cloud, Datacenters, ..
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CCGrid '11
Cluster Computing Environment
Compute cluster
LANFrontend
Meta-Data
Manager
I/O Server
Node
Meta
Data
DataCompute
Node
Compute
Node
I/O Server
NodeData
Compute
Node
I/O ServerNode
DataComputeNode
L
A
N
Storage cluster
LAN
4
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CCGrid '11
Trends for Computing Clusters in the Top 500 List
(http://www.top500.org)
Nov. 1996: 0/500 (0%) Nov. 2001: 43/500 (8.6%) Nov. 2006: 361/500 (72.2%)
Jun. 1997: 1/500 (0.2%) Jun. 2002: 80/500 (16%) Jun. 2007: 373/500 (74.6%)
Nov. 1997: 1/500 (0.2%) Nov. 2002: 93/500 (18.6%) Nov. 2007: 406/500 (81.2%)
Jun. 1998: 1/500 (0.2%) Jun. 2003: 149/500 (29.8%) Jun. 2008: 400/500 (80.0%)
Nov. 1998: 2/500 (0.4%) Nov. 2003: 208/500 (41.6%) Nov. 2008: 410/500 (82.0%)
Jun. 1999: 6/500 (1.2%) Jun. 2004: 291/500 (58.2%) Jun. 2009: 410/500 (82.0%)
Nov. 1999: 7/500 (1.4%) Nov. 2004: 294/500 (58.8%) Nov. 2009: 417/500 (83.4%)
Jun. 2000: 11/500 (2.2%) Jun. 2005: 304/500 (60.8%) Jun. 2010: 424/500 (84.8%)
Nov. 2000: 28/500 (5.6%) Nov. 2005: 360/500 (72.0%) Nov. 2010: 415/500 (83%)
Jun. 2001: 33/500 (6.6%) Jun. 2006: 364/500 (72.8%) Jun. 2011: To be announced
5
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CCGrid '11
Grid Computing Environment
6
Compute cluster
LANFrontend
Meta-Data
Manager
I/O Server
Node
Meta
Data
DataCompute
Node
Compute
Node
I/O ServerNode
DataComputeNode
I/O Server
NodeData
Compute
Node
L
A
N
Storage cluster
LAN
Compute cluster
LANFrontend
Meta-Data
Manager
I/O Server
Node
Meta
Data
DataCompute
Node
Compute
Node
I/O ServerNode
DataComputeNode
I/O Server
NodeData
Compute
Node
L
A
N
Storage cluster
LAN
Compute cluster
LANFrontend
Meta-Data
Manager
I/O Server
Node
Meta
Data
DataCompute
Node
Compute
Node
I/O Server
NodeData
Compute
Node
I/O Server
NodeData
Compute
Node
L
A
N
Storage cluster
LAN
WAN
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Multi-Tier Datacenters and Enterprise Computing
7
.
..
.
Enterprise Multi-tier Datacenter
Tier1 Tier3
Routers/
Servers
Switch
Database
ServerApplication
Server
Routers/
Servers
Routers/
Servers
Application
Server
Application
Server
Application
Server
Database
Server
Database
Server
Database
Server
Switch Switch
Routers/
Servers
Tier2
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Integrated High-End Computing Environments
Compute cluster
Meta-Data
Manager
I/O Server
Node
Meta
Data
DataCompute
Node
Compute
Node
I/O Server
NodeData
Compute
Node
I/O Server
NodeData
Compute
Node
L
A
NLANFrontend
Storage cluster
LAN/WAN
.
..
.
Enterprise Multi-tier Datacenter for Visualization and Mining
Tier1 Tier3
Routers/
Servers
Switch
Database
ServerApplication
Server
Routers/
Servers
Routers/
Servers
Application
ServerApplication
Server
Application
Server
Database
Server
Database
Server
Database
Server
Switch Switch
Routers/
Servers
Tier2
8
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Cloud Computing Environments
9
LAN
Physical Machine
VM VM
Physical Machine
VM VM
Physical Machine
VM VMVirtualFS
Meta-DataMeta
Data
I/O Server Data
I/O Server Data
I/O Server Data
I/O Server Data
Physical Machine
VM VM
Local Storage
Local Storage
Local Storage
Local Storage
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Hadoop Architecture
Underlying Hadoop DistributedFile System (HDFS)
Fault-tolerance by replicatingdata blocks
NameNode: stores information
on data blocks DataNodes: store blocks and
host Map-reduce computation
JobTracker: track jobs and
detect failure Model scales but high amount
of communication duringintermediate phases
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Memcached Architecture
Distributed Caching Layer
Allows to aggregate spare memory from multiple nodes
General purpose
Typically used to cache database queries, results of API calls
Scalable model, but typical usage very network intensive
11
Internet
Web-frontend
ServersMemcached
Servers
Database
Servers
System
Area
Network
System
Area
Network
CCGrid '11
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Good System Area Networks with excellent performance(low latency, high bandwidth and low CPU utilization) for
inter-processor communication (IPC) and I/O
Good Storage Area Networks high performance I/O
Good WAN connectivity in addition to intra-cluster
SAN/LAN connectivity
Quality of Service (QoS) for interactive applications
RAS (Reliability, Availability, and Serviceability)
With low cost
CCGrid '11
Networking and I/O Requirements
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Hardware components
Processing cores and memory
subsystem
I/O bus or links
Network adapters/switches
Software components
Communication stack
Bottlenecks can artificially
limit the network performance
the user perceives
CCGrid '11 13
Major Components in Computing Systems
P0
Core0 Core1
Core2 Core3
P1
Core0 Core1
Core2 Core3
Memory
MemoryI/
O
B
u
s
Network Adapter
Network
Switch
Processing
Bottlenecks
I/O Interface
Bottlenecks
Network
Bottlenecks
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Ex: TCP/IP, UDP/IP
Generic architecture for all networks
Host processor handles almost all aspects
of communication
Data buffering (copies on sender and
receiver) Data integrity (checksum)
Routing aspects (IP routing)
Signaling between different layers
Hardware interrupt on packet arrival ortransmission
Software signals between different layers
to handle protocol processing in different
priority levels
CCGrid '11
Processing Bottlenecks in Traditional Protocols
14
P0
Core0 Core1
Core2 Core3
P1
Core0 Core1
Core2 Core3
Memory
MemoryI
/O
B
u
s
Network Adapter
Network
Switch
Processing
Bottlenecks
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Traditionally relied on bus-based
technologies (last mile bottleneck)
E.g., PCI, PCI-X
One bit per wire
Performance increase through:
Increasing clock speed Increasing bus width
Not scalable:
Cross talk between bits
Skew between wires
Signal integrity makes it difficult to increase buswidth significantly, especially for high clock speeds
CCGrid '11
Bottlenecks in Traditional I/O Interfaces and Networks
15
PCI 1990 33MHz/32bit: 1.05Gbps (shared bidirectional)
PCI-X1998 (v1.0)
2003 (v2.0)
133MHz/64bit: 8.5Gbps (shared bidirectional)
266-533MHz/64bit: 17Gbps (shared bidirectional)
P0
Core0 Core1
Core2 Core3
P1
Core0 Core1
Core2 Core3
Memory
MemoryI
/
O
B
us
Network Adapter
Network
Switch
I/O Interface
Bottlenecks
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Network speeds saturated ataround 1Gbps
Features provided were limited
Commodity networks were not
considered scalable enough for verylarge-scale systems
CCGrid '11 16
Bottlenecks on Traditional Networks
Ethernet (1979 - ) 10 Mbit/sec
Fast Ethernet (1993 -) 100 Mbit/sec
Gigabit Ethernet (1995 -) 1000 Mbit /sec
ATM (1995 -) 155/622/1024 Mbit/sec
Myrinet (1993 -) 1 Gbit/sec
Fibre Channel (1994 -) 1 Gbit/sec
P0
Core0 Core1
Core2 Core3
P1
Core0 Core1
Core2 Core3
Memory
MemoryI
/
O
B
u
s
Network Adapter
Network
Switch
Network
Bottlenecks
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Industry Networking Standards InfiniBand and High-speed Ethernet were introduced into
the market to address these bottlenecks
InfiniBand aimed at all three bottlenecks (protocol
processing, I/O bus, and network speed)
Ethernet aimed at directly handling the network speed
bottleneck and relying on complementary technologies to
alleviate the protocol processing and I/O bus bottlenecks
CCGrid '11 17
Motivation for InfiniBand and High-speed Ethernet
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Introduction
Why InfiniBand and High-speed Ethernet?
Overview of IB, HSE, their Convergence and Features
IB and HSE HW/SW Products and Installations
Sample Case Studies and Performance Numbers
Conclusions and Final Q&A
CCGrid '11
Presentation Overview
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IB Trade Association was formed with seven industry leaders
(Compaq, Dell, HP, IBM, Intel, Microsoft, and Sun)
Goal: To design a scalable and high performance communication
and I/O architecture by taking an integrated view of computing,
networking, and storage technologies Many other industry participated in the effort to define the IB
architecture specification
IB Architecture (Volume 1, Version 1.0) was released to public
on Oct 24, 2000
Latest version 1.2.1 released January 2008
http://www.infinibandta.org
CCGrid '11
IB Trade Association
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10GE Alliance formed by several industry leaders to take
the Ethernet family to the next speed step
Goal: To achieve a scalable and high performance
communication architecture while maintaining backward
compatibility with Ethernet
http://www.ethernetalliance.org
40-Gbps (Servers) and 100-Gbps Ethernet (Backbones,
Switches, Routers): IEEE 802.3 WG Energy-efficient and power-conscious protocols
On-the-fly link speed reduction for under-utilized links
CCGrid '11
High-speed Ethernet Consortium (10GE/40GE/100GE)
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Network speed bottlenecks
Protocol processing bottlenecks
I/O interface bottlenecks
CCGrid '11 21
Tackling Communication Bottlenecks with IB and HSE
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Bit serial differential signaling Independent pairs of wires to transmit independent
data (called a lane)
Scalable to any number of lanes
Easy to increase clock speed of lanes (since each laneconsists only of a pair of wires)
Theoretically, no perceived limit on the
bandwidth
CCGrid '11
Network Bottleneck Alleviation: InfiniBand (Infinite
Bandwidth) and High-speed Ethernet (10/40/100 GE)
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CCGrid '11
Network Speed Acceleration with IB and HSE
Ethernet (1979 - ) 10 Mbit/sec
Fast Ethernet (1993 -) 100 Mbit/sec
Gigabit Ethernet (1995 -) 1000 Mbit /sec
ATM (1995 -) 155/622/1024 Mbit/sec
Myrinet (1993 -) 1 Gbit/sec
Fibre Channel (1994 -) 1 Gbit/sec
InfiniBand (2001 -) 2 Gbit/sec (1X SDR)
10-Gigabit Ethernet (2001 -) 10 Gbit/sec
InfiniBand (2003 -) 8 Gbit/sec (4X SDR)
InfiniBand (2005 -) 16 Gbit/sec (4X DDR)
24 Gbit/sec (12X SDR)
InfiniBand (2007 -) 32 Gbit/sec (4X QDR)
40-Gigabit Ethernet (2010 -) 40 Gbit/sec
InfiniBand (2011 -) 56 Gbit/sec (4X FDR)
InfiniBand (2012 -) 100 Gbit/sec (4X EDR)
20 times in the last 9 years
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2005 - 2006 - 2007 - 2008 - 2009 - 2010 - 2011
Bandwidthpe
rdirection(Gbps)
32G-IB-DDR
48G-IB-DDR
96G-IB-QDR
48G-IB-QDR
200G-IB-EDR
112G-IB-FDR
300G-IB-EDR
168G-IB-FDR
8x HDR
12x HDR
# ofLanes perdirection
Per Lane & Rounded Per Link Bandwidth (Gb/s)
4G-IBDDR
8G-IBQDR
14G-IB-FDR(14.025)
26G-IB-EDR(25.78125)
12 48+48 96+96 168+168 300+300
8 32+32 64+64 112+112 200+200
4 16+16 32+32 56+56 100+100
1 4+4 8+8 14+14 25+25
NDR = Next Data Rate
HDR = High Data Rate
EDR = Enhanced Data Rate
FDR = Fourteen Data Rate
QDR = Quad Data Rate
DDR = Double Data RateSDR = Single Data Rate (not shown)
x12
x8
x1
2015
12x NDR
8x NDR
32G-IB-QDR
100G-IB-EDR
56G-IB-FDR
16G-IB-DDR
4x HDR
x4
4x NDR
8G-IB-QDR
25G-IB-EDR
14G-IB-FDR
1x HDR
1x NDR
InfiniBand Link Speed Standardization Roadmap
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Network speed bottlenecks
Protocol processing bottlenecks
I/O interface bottlenecks
CCGrid '11 25
Tackling Communication Bottlenecks with IB and HSE
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Intelligent Network Interface Cards Support entire protocol processing completely in hardware
(hardware protocol offload engines)
Provide a rich communication interface to applications
User-level communication capability
Gets rid of intermediate data buffering requirements
No software signaling between communication layers
All layers are implemented on a dedicated hardware unit, and not
on a sharedhost CPU
CCGrid '11
Capabilities of High-Performance Networks
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Fast Messages (FM)
Developed by UIUC
Myricom GM
Proprietary protocol stack from Myricom
These network stacks set the trend for high-performancecommunication requirements
Hardware offloaded protocol stack
Support for fast and secure user-level access to the protocol stack
Virtual Interface Architecture (VIA) Standardized by Intel, Compaq, Microsoft
Precursor to IB
CCGrid '11
Previous High-Performance Network Stacks
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Some IB models have multiple hardware accelerators E.g., Mellanox IB adapters
Protocol Offload Engines
Completely implement ISO/OSI layers 2-4 (link layer, network layer
and transport layer) in hardware
Additional hardware supported features also present
RDMA, Multicast, QoS, Fault Tolerance, and many more
CCGrid '11
IB Hardware Acceleration
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Interrupt Coalescing
Improves throughput, but degrades latency
Jumbo Frames
No latency impact; Incompatible with existing switches
Hardware Checksum Engines
Checksum performed in hardware significantly faster
Shown to have minimal benefit independently
Segmentation Offload Engines (a.k.a. Virtual MTU)
Host processor thinks that the adapter supports large Jumbo
frames, but the adapter splits it into regular sized (1500-byte) frames Supported by most HSE products because of its backward
compatibility considered regular Ethernet
Heavily used in the server-on-steroids model
High performance servers connected to regular clients
CCGrid '11
Ethernet Hardware Acceleration
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TCP Offload Engines (TOE)
Hardware Acceleration for the entire TCP/IP stack
Initially patented by Tehuti Networks
Actually refers to the IC on the network adapter that implements
TCP/IP In practice, usually referred to as the entire network adapter
Internet Wide-Area RDMA Protocol (iWARP)
Standardized by IETF and the RDMA Consortium
Support acceleration features (like IB) for Ethernet
http://www.ietf.org & http://www.rdmaconsortium.org
CCGrid '11
TOE and iWARP Accelerators
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Also known as Datacenter Ethernet or Lossless Ethernet
Combines a number of optional Ethernet standards into one umbrella
as mandatory requirements
Sample enhancements include:
Priority-based flow-control: Link-level flow control for each Class ofService (CoS)
Enhanced Transmission Selection (ETS): Bandwidth assignment to
each CoS
Datacenter Bridging Exchange Protocols (DBX): Congestionnotification, Priority classes
End-to-end Congestion notification: Per flow congestion control to
supplement per link flow control
CCGrid '11
Converged (Enhanced) Ethernet (CEE or CE)
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Network speed bottlenecks
Protocol processing bottlenecks
I/O interface bottlenecks
CCGrid '11 32
Tackling Communication Bottlenecks with IB and HSE
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InfiniBand initially intended to replace I/O bus
technologies with networking-like technology
That is, bit serial differential signaling
With enhancements in I/O technologies that use a similar
architecture (HyperTransport, PCI Express), this has becomemostly irrelevant now
Both IB and HSE today come as network adapters that plug
into existing I/O technologies
CCGrid '11
Interplay with I/O Technologies
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Recent trends in I/O interfaces show that they are nearly
matching head-to-head with network speeds (though they
still lag a little bit)
CCGrid '11
Trends in I/O Interfaces with Servers
PCI 1990 33MHz/32bit: 1.05Gbps (shared bidirectional)
PCI-X 1998 (v1.0)2003 (v2.0)
133MHz/64bit: 8.5Gbps (shared bidirectional)266-533MHz/64bit: 17Gbps (shared bidirectional)
AMD HyperTransport (HT)2001 (v1.0), 2004 (v2.0)
2006 (v3.0), 2008 (v3.1)
102.4Gbps (v1.0), 179.2Gbps (v2.0)
332.8Gbps (v3.0), 409.6Gbps (v3.1)
(32 lanes)
PCI-Express (PCIe)by Intel
2003 (Gen1), 2007 (Gen2)2009 (Gen3 standard)
Gen1: 4X (8Gbps), 8X (16Gbps), 16X (32Gbps)
Gen2: 4X (16Gbps), 8X (32Gbps), 16X (64Gbps)
Gen3: 4X (~32Gbps), 8X (~64Gbps), 16X (~128Gbps)
Intel QuickPath
Interconnect (QPI)2009 153.6-204.8Gbps (20 lanes)
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Introduction
Why InfiniBand and High-speed Ethernet?
Overview of IB, HSE, their Convergence and Features
IB and HSE HW/SW Products and Installations
Sample Case Studies and Performance Numbers
Conclusions and Final Q&A
CCGrid '11
Presentation Overview
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InfiniBand
Architecture and Basic Hardware Components Communication Model and Semantics
Novel Features
Subnet Management and Services
High-speed Ethernet Family
Internet Wide Area RDMA Protocol (iWARP)
Alternate vendor-specific protocol stacks
InfiniBand/Ethernet Convergence Technologies
Virtual Protocol Interconnect (VPI)
(InfiniBand) RDMA over Ethernet (RoE)
(InfiniBand) RDMA over Converged (Enhanced) Ethernet (RoCE)
CCGrid '11
IB, HSE and their Convergence
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CCGrid '11 37
Comparing InfiniBand with Traditional Networking Stack
Application LayerMPI, PGAS, File Systems
Transport Layer
OpenFabrics Verbs
RC (reliable), UD (unreliable)
Link LayerFlow-control, Error Detection
Physical Layer
InfiniBand
Copper or Optical
HTTP, FTP, MPI,
File Systems
Routing
Physical Layer
Link Layer
Network Layer
Transport Layer
Application Layer
Traditional Ethernet
Sockets Interface
TCP, UDP
Flow-control and
Error Detection
Copper, Optical or Wireless
Network Layer Routing
OpenSM (management tool)
DNS management tools
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InfiniBand
Architecture and Basic Hardware Components
Communication Model and Semantics
Communication Model
Memory registration and protection
Channel and memory semantics
Novel Features
Hardware Protocol Offload
Link, network and transport layer features
Subnet Management and Services
CCGrid '11
IB Overview
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Used by processing and I/O units to
connect to fabric
Consume & generate IB packets
Programmable DMA engines with
protection features
May have multiple ports
Independent buffering channeled
through Virtual Lanes
Host Channel Adapters (HCAs)
CCGrid '11
Components: Channel Adapters
39
C
Port
VLVL
VL
Port
VLVL
VL
Port
VLVL
VL
DMA
Memory
QP
QP
QP
QP
MTP
SMA
Transport
Channel Adapter
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Relay packets from a link to another Switches: intra-subnet
Routers: inter-subnet
May support multicast
CCGrid '11
Components: Switches and Routers
40
Packet Relay
Port
VLVL
VL
Port
VLVL
VL
Port
VLVL
VL
Switch
GRH Packet Relay
Port
VLVL
VL
Port
VLVL
VL
Port
VLVL
VL
Router
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Network Links
Copper, Optical, Printed Circuit wiring on Back Plane Not directly addressable
Traditional adapters built for copper cabling
Restricted by cable length (signal integrity)
For example, QDR copper cables are restricted to 7m
Intel Connects: Optical cables with Copper-to-optical
conversion hubs (acquired by Emcore)
Up to 100m length
550 picosecondscopper-to-optical conversion latency
Available from other vendors (Luxtera)
Repeaters (Vol. 2 of InfiniBand specification)
CCGrid '11
Components: Links & Repeaters
(Courtesy Intel)
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InfiniBand
Architecture and Basic Hardware Components
Communication Model and Semantics
Communication Model
Memory registration and protection
Channel and memory semantics
Novel Features
Hardware Protocol Offload
Link, network and transport layer features
Subnet Management and Services
CCGrid '11
IB Overview
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CCGrid '11
IB Communication Model
Basic InfiniBand
Communication
Semantics
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Each QP has two queues
Send Queue (SQ)
Receive Queue (RQ)
Work requests are queued to the QP
(WQEs: Wookies)
QP to be linked to a Complete Queue
(CQ)
Gives notification of operation
completion from QPs Completed WQEs are placed in the
CQ with additional information
(CQEs: Cookies)
CCGrid '11
Queue Pair Model
InfiniBand Device
CQQP
Send Recv
WQEs CQEs
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1. Registration Request
Send virtual address and length
2. Kernel handles virtual->physical
mapping and pins region into
physical memory Process cannot map memory
that it does not own (security !)
3. HCA caches the virtual to physical
mapping and issues a handle Includes an l_keyand r_key
4. Handle is returned to application
CCGrid '11
Memory Registration
Before we do any communication:
All memory used for communication mustbe registered
1
3
4
Process
Kernel
HCA/RNIC
2
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To send or receive data the l_key
must be provided to the HCA
HCA verifies access to local
memory
For RDMA, initiator must have the
r_key for the remote virtual address
Possibly exchanged with a
send/recv
r_key is not encrypted in IB
CCGrid '11
Memory Protection
HCA/NIC
Kernel
Process
l_key
r_keyis needed for RDMA operations
For security, keys are required for all
operations that touch buffers
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CCGrid '11
Communication in the Channel Semantics
(Send/Receive Model)
InfiniBand Device
Memory Memory
InfiniBand Device
CQQP
Send Recv
Memory
Segment
Send WQE contains information about the
send buffer (multiple non-contiguous
segments)
Processor Processor
CQQP
Send Recv
Memory
Segment
Receive WQE contains information on the receive
buffer (multiple non-contiguous segments);
Incoming messages have to be matched to a
receive WQE to know where to place
Hardware ACK
Memory
Segment
Memory
Segment
Memory
Segment
Processor is involved only to:
1. Post receive WQE
2. Post send WQE
3. Pull out completed CQEs from the CQ
47
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CCGrid '11
Communication in the Memory Semantics (RDMA Model)
InfiniBand Device
Memory Memory
InfiniBand Device
CQQP
Send Recv
Memory
Segment
Send WQE contains information about the
send buffer (multiple segments) and the
receive buffer (single segment)
Processor Processor
CQQP
Send Recv
Memory
Segment
Hardware ACK
Memory
Segment
Memory
SegmentInitiator processor is involved only to:
1. Post send WQE
2. Pull out completed CQE from the send CQ
No involvement from the target processor
48
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InfiniBand Device
CCGrid '11
Communication in the Memory Semantics (Atomics)
Memory Memory
InfiniBand Device
CQQP
Send Recv
Memory
Segment
Send WQE contains information about the
send buffer (single 64-bit segment) and the
receive buffer (single 64-bit segment)
Processor Processor
CQQP
Send Recv
49
Source
Memory
Segment
OP
Destination
Memory
Segment Initiator processor is involved only to:
1. Post send WQE
2. Pull out completed CQE from the send CQ
No involvement from the target processor
IB supports compare-and-swap and
fetch-and-add atomic operations
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InfiniBand
Architecture and Basic Hardware Components
Communication Model and Semantics
Communication Model
Memory registration and protection
Channel and memory semantics
Novel Features
Hardware Protocol Offload
Link, network and transport layer features
Subnet Management and Services
CCGrid '11
IB Overview
50
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CCGrid '11
Hardware Protocol Offload
Complete
Hardware
Implementations
Exist
51
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Buffering and Flow Control
Virtual Lanes, Service Levels and QoS
Switching and Multicast
CCGrid '11
Link/Network Layer Capabilities
52
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IB provides three-levels of communication throttling/control
mechanisms Link-level flow control (link layer feature)
Message-level flow control (transport layer feature): discussed later
Congestion control (part of the link layer features)
IB provides an absolute credit-based flow-control
Receiver guarantees that enough space is allotted for N blocks of data
Occasional update of available credits by the receiver
Has no relation to the number of messages, but only to thetotal amount of data being sent
One 1MB message is equivalent to 1024 1KB messages (except for
rounding off at message boundaries)
CCGrid '11
Buffering and Flow Control
53
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Multiple virtual links within
same physical link
Between 2 and 16
Separate buffers and flow
control Avoids Head-of-Line
Blocking
VL15: reserved for
management Each port supports one or
more data VL
CCGrid '11
Virtual Lanes
54
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Service Level (SL):
Packets may operate at one of 16 different SLs
Meaning not defined by IB
SL to VL mapping:
SL determines which VL on the next link is to be used Each port (switches, routers, end nodes) has a SL to VL mapping
table configured by the subnet management
Partitions:
Fabric administration (through Subnet Manager) may assignspecific SLs to different partitions to isolate traffic flows
CCGrid '11
Service Levels and QoS
55
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InfiniBand Virtual Lanes
allow the multiplexing of
multiple independent logical
traffic flows on the same
physical link Providing the benefits of
independent, separate
networks while eliminating
the cost and difficulties
associated with maintaining
two or more networks
CCGrid '11
Traffic Segregation Benefits
(Courtesy: Mellanox Technologies)
Routers, Switches
VPNs, DSLAMs
Storage Area Network
RAID, NAS, Backup
IPC, Load Balancing, Web Caches, ASP
InfiniBand
Network
Virtual Lanes
Servers
Fabric
ServersServers
IP Network
InfiniBand
Fabric
56
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Each port has one or more associated LIDs (Local
Identifiers)
Switches look up which port to forward a packet to based on its
destination LID (DLID)
This information is maintained at the switch
For multicast packets, the switch needs to maintain
multiple output ports to forward the packet to
Packet is replicated to each appropriate output port
Ensures at-most once delivery & loop-free forwarding There is an interface for a group management protocol
Create, join/leave, prune, delete group
CCGrid '11
Switching (Layer-2 Routing) and Multicast
57
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Basic unit of switching is a crossbar
Current InfiniBand products use either 24-port (DDR) or 36-port(QDR) crossbars
Switches available in the market are typically collections of
crossbars within a single cabinet
Do not confuse non-blocking switches with crossbars
Crossbars provide all-to-all connectivity to all connected nodes
For any random node pair selection, all communication is non-blocking
Non-blocking switches provide a fat-tree of many crossbars For any random node pair selection, there exists a switch
configuration such that communication is non-blocking
If the communication pattern changes, the same switch configuration
might no longer provide fully non-blocking communication
CCGrid '11 58
Switch Complex
/
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Someone has to setup the forwarding tables and
give every port an LID Subnet Manager does this work
Different routing algorithms give different paths
CCGrid '11
IB Switching/Routing: An Example
Leaf Blocks
Spine Blocks
P1P2 DLID Out-Port
2 1
4 4
Forwarding TableLID: 2LID: 4
1 2 3 4
59
An Example IB Switch Block Diagram (Mellanox 144-Port) Switching: IB supports
Virtual Cut Through (VCT)
Routing: Unspecified by IB SPEC
Up*/Down*, Shift are popular
routing engines supported by OFED
Fat-Tree is a popular
topology for IB Cluster
Different over-subscription
ratio may be used
Other topologies are also
being used
3D Torus (Sandia Red Sky)
and SGI Altix (Hypercube)
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Similar to basic switching, except
sender can utilize multiple LIDs associated to the same
destination port
Packets sent to one DLID take a fixed path
Different packets can be sent using different DLIDs
Each DLID can have a different path (switch can be configured
differently for each DLID)
Can cause out-of-order arrival of packets
IB uses a simplistic approach:
If packets in one connection arrive out-of-order, they are dropped
Easier to use different DLIDs for different connections
This is what most high-level libraries using IB do!
CCGrid '11 60
More on Multipathing
l i l
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CCGrid '11
IB Multicast Example
61
H d P l Offl d
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CCGrid '11
Hardware Protocol Offload
Complete
Hardware
Implementations
Exist
62
IB T S i
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Each transport service can have zero or more QPs
associated with it
E.g., you can have four QPs based on RC and one QP based on UD
CCGrid '11
IB Transport Services
Service TypeConnection
OrientedAcknowledged Transport
Reliable Connection Yes Yes IBA
Unreliable Connection Yes No IBA
Reliable Datagram No Yes IBA
Unreliable Datagram No No IBA
RAW Datagram No No Raw
63
T d ff i Diff t T t T
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CCGrid '11
Trade-offs in Different Transport Types
64
Attribute Reliable
Connection
Reliable
Datagram
eXtended
Reliable
Connection
Unreliable
Connection
Unreliable
Datagram
Raw
Datagram
Scalability
(M processes, N
nodes)
M2N QPs
per HCA
M QPs
per HCA
MN QPs
per HCA
M2N QPs
per HCA
M QPs
per HCA
1 QP
per HCA
R
eliability
Corrupt
data
detected
Yes
Data
Delivery
Guarantee
Data delivered exactly once No guarantees
Data Order
Guarantees Per connectionOne source to
multiple
destinations
Per connection
Unordered,
duplicate data
detected
No No
Data LossDetected Yes No No
Error
Recovery
Errors (retransmissions, alternate path, etc.)
handled by transport layer. Client only involved in
handling fatal errors (links broken, protection
violation, etc.)
Packets with
errors and
sequence
errors are
reported to
responder
None None
T t L C biliti
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Data Segmentation
Transaction Ordering
Message-level Flow Control
Static Rate Control and Auto-negotiation
CCGrid '11
Transport Layer Capabilities
65
D t S t ti
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IB transport layer provides a message-level communication
granularity, not byte-level (unlike TCP)
Application can hand over a large message
Network adapter segments it to MTU sized packets
Single notification when the entire message is transmitted or
received (not per packet)
Reduced host overhead to send/receive messages Depends on the number of messages, not the number of bytes
CCGrid '11 66
Data Segmentation
T ti O d i
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IB follows a strong transaction ordering for RC
Sender network adapter transmits messages in the order
in which WQEs were posted
Each QP utilizes a single LID
All WQEs posted on same QP take the same path
All packets are received by the receiver in the same order
All receive WQEs are completed in the order in which they were
posted
CCGrid '11
Transaction Ordering
67
Message le el Flo Control
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Also called as End-to-end Flow-control
Does not depend on the number of network hops
Separate from Link-level Flow-Control
Link-level flow-control only relies on the number of bytes being
transmitted, not the number of messages Message-level flow-control only relies on the number of messages
transferred, not the number of bytes
If 5 receive WQEs are posted, the sender can send 5
messages (can post 5 send WQEs) If the sent messages are larger than what the receive buffers are
posted, flow-control cannot handle it
CCGrid '11 68
Message-level Flow-Control
Static Rate Control and Auto Negotiation
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IB allows link rates to be statically changed
On a 4X link, we can set data to be sent at 1X
For heterogeneous links, rate can be set to the lowest link rate
Useful for low-priority traffic
Auto-negotiation also available E.g., if you connect a 4X adapter to a 1X switch, data is
automatically sent at 1X rate
Only fixed settings available
Cannot set rate requirement to 3.16 Gbps, for example
CCGrid '11 69
Static Rate Control and Auto-Negotiation
IB Overview
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InfiniBand
Architecture and Basic Hardware Components
Communication Model and Semantics
Communication Model
Memory registration and protection
Channel and memory semantics
Novel Features
Hardware Protocol Offload
Link, network and transport layer features
Subnet Management and Services
CCGrid '11
IB Overview
70
Concepts in IB Management
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Agents
Processes or hardware units running on each adapter, switch,
router (everything on the network)
Provide capability to query and set parameters
Managers
Make high-level decisions and implement it on the network fabric
using the agents
Messaging schemes
Used for interactions between the manager and agents (or
between agents)
Messages
CCGrid '11
Concepts in IB Management
71
Subnet Manager
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Inactive
Links
CCGrid '11
Subnet Manager
Active
Links
Compute
Node
Switch
SubnetManager
Inactive
Link
Multicast Join
Multicast
Setup
Multicast Join
Multicast
Setup
72
IB HSE and their Convergence
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InfiniBand
Architecture and Basic Hardware Components
Communication Model and Semantics
Novel Features
Subnet Management and Services
High-speed Ethernet Family
Internet Wide Area RDMA Protocol (iWARP)
Alternate vendor-specific protocol stacks
InfiniBand/Ethernet Convergence Technologies
Virtual Protocol Interconnect (VPI)
(InfiniBand) RDMA over Ethernet (RoE)
(InfiniBand) RDMA over Converged (Enhanced) Ethernet (RoCE)
CCGrid '11
IB, HSE and their Convergence
73
HSE Overview
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High-speed Ethernet Family
Internet Wide-Area RDMA Protocol (iWARP)
Architecture and Components
Features
Out-of-order data placement
Dynamic and Fine-grained Data Rate control
Multipathing using VLANs
Existing Implementations of HSE/iWARP
Alternate Vendor-specific Stacks
MX over Ethernet (for Myricom 10GE adapters)
Datagram Bypass Layer (for Myricom 10GE adapters)
Solarflare OpenOnload (for Solarflare 10GE adapters)
CCGrid '11
HSE Overview
74
IB and HSE RDMA Models: Commonalities and
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CCGrid '11
IB and HSE RDMA Models: Commonalities and
Differences
IB iWARP/HSE
Hardware Acceleration Supported Supported
RDMA Supported Supported
Atomic Operations Supported Not supported
Multicast Supported Supported
Congestion Control Supported Supported
Data Placement Ordered Out-of-order
Data Rate-control Static and Coarse-grained Dynamic and Fine-grained
QoS Prioritization Prioritization andFixed Bandwidth QoS
Multipathing Using DLIDs Using VLANs
75
iWARP Architecture and Components
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RDMA Protocol (RDMAP)
Feature-rich interface
Security Management
Remote Direct Data Placement (RDDP)
Data Placement and Delivery
Multi Stream Semantics
Connection Management
Marker PDU Aligned (MPA)
Middle Box Fragmentation
Data Integrity (CRC)
CCGrid '11
iWARP Architecture and Components
RDDP
Application or Library
Hardware
User
SCTP
IP
Device Driver
Network Adapter
(e.g., 10GigE)
iWARP Offload Engines
TCP
RDMAP
MPA
(Courtesy iWARP Specification)
76
HSE Overview
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High-speed Ethernet Family
Internet Wide-Area RDMA Protocol (iWARP)
Architecture and Components
Features
Out-of-order data placement
Dynamic and Fine-grained Data Rate control
Existing Implementations of HSE/iWARP
Alternate Vendor-specific Stacks
MX over Ethernet (for Myricom 10GE adapters)
Datagram Bypass Layer (for Myricom 10GE adapters)
Solarflare OpenOnload (for Solarflare 10GE adapters)
CCGrid '11
HSE Overview
77
Decoupled Data Placement and Data Delivery
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Place data as it arrives, whether in or out-of-order
If data is out-of-order, place it at the appropriate offset
Issues from the applications perspective:
Second half of the message has been placed does not mean that
the first half of the message has arrived as well
If one message has been placed, it does not mean that that the
previous messages have been placed
Issues from protocol stacks perspective
The receiver network stack has to understand each frame of data If the frame is unchanged during transmission, this is easy!
The MPA protocol layer adds appropriate information at regular
intervals to allow the receiver to identify fragmented frames
CCGrid '11
Decoupled Data Placement and Data Delivery
78
Dynamic and Fine-grained Rate Control
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Part of the Ethernet standard, not iWARP
Network vendors use a separate interface to support it
Dynamic bandwidth allocation to flows based on interval
between two packets in a flow
E.g., one stall for every packet sent on a 10 Gbps network refers to
a bandwidth allocation of 5 Gbps
Complicated because of TCP windowing behavior
Important for high-latency/high-bandwidth networks
Large windows exposed on the receiver side
Receiver overflow controlled through rate control
CCGrid '11
Dynamic and Fine grained Rate Control
79
Prioritization and Fixed Bandwidth QoS
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Can allow for simple prioritization:
E.g., connection 1 performs better than connection 2
8 classes provided (a connection can be in any class)
Similar to SLs in InfiniBand
Two priority classes for high-priority traffic
E.g., management traffic or your favorite application
Or can allow for specific bandwidth requests:
E.g., can request for 3.62 Gbps bandwidth
Packet pacing and stalls used to achieve this
Query functionality to find out remaining bandwidth
CCGrid '11
Prioritization and Fixed Bandwidth QoS
80
HSE Overview
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High-speed Ethernet Family
Internet Wide-Area RDMA Protocol (iWARP)
Architecture and Components
Features
Out-of-order data placement
Dynamic and Fine-grained Data Rate control
Existing Implementations of HSE/iWARP
Alternate Vendor-specific Stacks
MX over Ethernet (for Myricom 10GE adapters)
Datagram Bypass Layer (for Myricom 10GE adapters)
Solarflare OpenOnload (for Solarflare 10GE adapters)
CCGrid '11
HSE Overview
81
Software iWARP based Compatibility
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Regular Ethernet adapters and
TOEs are fully compatible Compatibility with iWARP
required
Software iWARP emulates the
functionality of iWARP on the
host
Fully compatible with hardware
iWARP
Internally utilizes host TCP/IP stack
CCGrid '11
Software iWARP based Compatibility
82
Wide
Area
Network
Distributed Cluster
Environment
Regular Ethernet
Cluster
iWARP
Cluster
TOE
Cluster
Different iWARP Implementations
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CCGrid '11
Different iWARP Implementations
Regular Ethernet Adapters
Application
High Performance Sockets
Sockets
Network Adapter
TCP
IP
Device Driver
Offloaded TCP
Offloaded IP
Software
iWARP
TCP Offload Engines
Application
High Performance Sockets
Sockets
Network Adapter
TCP
IP
Device Driver
Offloaded TCP
Offloaded IP
Offloaded iWARP
iWARP compliant
Adapters
Application
Kernel-level
iWARP
TCP (Modified with MPA)
IP
Device Driver
Network Adapter
Sockets
Application
User-level iWARP
IP
Sockets
TCP
Device Driver
Network Adapter
OSU, OSC, IBM OSU, ANL Chelsio, NetEffect (Intel)
83
HSE Overview
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High-speed Ethernet Family
Internet Wide-Area RDMA Protocol (iWARP)
Architecture and Components
Features
Out-of-order data placement
Dynamic and Fine-grained Data Rate control
Multipathing using VLANs
Existing Implementations of HSE/iWARP
Alternate Vendor-specific Stacks
MX over Ethernet (for Myricom 10GE adapters)
Datagram Bypass Layer (for Myricom 10GE adapters)
Solarflare OpenOnload (for Solarflare 10GE adapters)
CCGrid '11
HSE Overview
84
Myrinet Express (MX)
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Proprietary communication layer developed by Myricom for
their Myrinet adapters Third generation communication layer (after FM and GM)
Supports Myrinet-2000 and the newer Myri-10G adapters
Low-level MPI-like messaging layer
Almost one-to-one match with MPI semantics (including connection-
less model, implicit memory registration and tag matching)
Later versions added some more advanced communication methods
such as RDMA to support other programming models such as ARMCI
(low-level runtime for the Global Arrays PGAS library)
Open-MX
New open-source implementation of the MX interface for non-
Myrinet adapters from INRIA, France
CCGrid '11 85
Myrinet Express (MX)
Datagram Bypass Layer (DBL)
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Another proprietary communication layer developed by
Myricom Compatible with regular UDP sockets (embraces and extends)
Idea is to bypass the kernel stack and give UDP applications direct
access to the network adapter
High performance and low-jitter
Primary motivation: Financial market applications (e.g.,
stock market)
Applications prefer unreliable communication
Timeliness is more important than reliability
This stack is covered by NDA; more details can be
requested from Myricom
CCGrid '11 86
Datagram Bypass Layer (DBL)
Solarflare Communications: OpenOnload Stack
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CCGrid '11
p
87
Typical HPC Networking StackTypical Commodity Networking Stack
HPC Networking Stack provides many
performance benefits, but has limitationsfor certain types of scenarios, especially
where applications tend to fork(), exec()
and need asynchronous advancement (per
application)
Solarflare approach to networking stack
Solarflare approach:
Network hardware provides user-safe
interface to route packets directly to apps
based on flow information in headers
Protocol processing can happen in both
kernel and user space
Protocol state shared between app and
kernel using shared memory
Courtesy Solarflare communications (www.openonload.org/openonload-google-talk.pdf)
IB, HSE and their Convergence
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InfiniBand
Architecture and Basic Hardware Components
Communication Model and Semantics
Novel Features
Subnet Management and Services
High-speed Ethernet Family
Internet Wide Area RDMA Protocol (iWARP)
Alternate vendor-specific protocol stacks
InfiniBand/Ethernet Convergence Technologies
Virtual Protocol Interconnect (VPI)
(InfiniBand) RDMA over Ethernet (RoE) (InfiniBand) RDMA over Converged (Enhanced) Ethernet (RoCE)
CCGrid '11
, g
88
Virtual Protocol Interconnect (VPI)
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Single network firmware to support
both IB and Ethernet
Autosensing of layer-2 protocol
Can be configured to automatically
work with either IB or Ethernet
networks Multi-port adapters can use one
port on IB and another on Ethernet
Multiple use modes:
Datacenters with IB inside thecluster and Ethernet outside
Clusters with IB network and
Ethernet management
CCGrid '11
( )
IB Link Layer
IB Port Ethernet Port
Hardware
TCP/IP
support
Ethernet
Link Layer
IB Network
LayerIP
IB Transport
LayerTCP
IB Verbs Sockets
Applications
89
(InfiniBand) RDMA over Ethernet (IBoE or RoE)
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Native convergence of IB network and transport
layers with Ethernet link layer
IB packets encapsulated in Ethernet frames
IB network layer already uses IPv6 frames
Pros:
Works natively in Ethernet environments (entire
Ethernet management ecosystem is available)
Has all the benefits of IB verbs
Cons:
Network bandwidth might be limited to Ethernet
switches: 10GE switches available; 40GE yet toarrive; 32 Gbps IB available
Some IB native link-layer features are optional in
(regular) Ethernet
Approved by OFA board to be included into OFED
CCGrid '11
( ) ( )
Ethernet
IB Network
IB Transport
IB Verbs
Application
Hardware
90
(InfiniBand) RDMA over Converged (Enhanced) Ethernet
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Very similar to IB over Ethernet
Often used interchangeably with IBoE
Can be used to explicitly specify link layer is
Converged (Enhanced) Ethernet (CE)
Pros:
Works natively in Ethernet environments (entireEthernet management ecosystem is available)
Has all the benefits of IB verbs
CE is very similar to the link layer of native IB, so
there are no missing features
Cons:
Network bandwidth might be limited to Ethernet
switches: 10GE switches available; 40GE yet to
arrive; 32 Gbps IB available
CCGrid '11
( ) g ( )
(RoCE)
CE
IB Network
IB Transport
IB Verbs
Application
Hardware
91
IB and HSE: Feature Comparison
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CCGrid '11
p
IB iWARP/HSE RoE RoCE
Hardware Acceleration Yes Yes Yes Yes
RDMA Yes Yes Yes Yes
Congestion Control Yes Optional Optional Yes
Multipathing Yes Yes Yes Yes
Atomic Operations Yes No Yes Yes
Multicast Optional No Optional Optional
Data Placement Ordered Out-of-order Ordered Ordered
Prioritization Optional Optional Optional Yes
Fixed BW QoS (ETS) No Optional Optional Yes
Ethernet Compatibility No Yes Yes Yes
TCP/IP CompatibilityYes
(using IPoIB)Yes
Yes
(using IPoIB)
Yes
(using IPoIB)
92
Presentation Overview
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Introduction
Why InfiniBand and High-speed Ethernet?
Overview of IB, HSE, their Convergence and Features
IB and HSE HW/SW Products and Installations
Sample Case Studies and Performance Numbers
Conclusions and Final Q&A
CCGrid '11 93
IB Hardware Products
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Many IB vendors: Mellanox+Voltaire and Qlogic
Aligned with many server vendors: Intel, IBM, SUN, Dell
And many integrators: Appro, Advanced Clustering, Microway
Broadly two kinds of adapters
Offloading (Mellanox) and Onloading (Qlogic)
Adapters with different interfaces:
Dual port 4X with PCI-X (64 bit/133 MHz), PCIe x8, PCIe 2.0 and HT
MemFree Adapter
No memory on HCA Uses System memory (through PCIe)
Good for LOM designs (Tyan S2935, Supermicro 6015T-INFB)
Different speeds
SDR (8 Gbps), DDR (16 Gbps) and QDR (32 Gbps)
Some 12X SDR adapters exist as well (24 Gbps each way)
New ConnectX-2 adapter from Mellanox supports offload for
collectives (Barrier, Broadcast, etc.)
CCGrid '11 94
Tyan Thunder S2935 Board
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CCGrid '11
(Courtesy Tyan)
Similar boards from Supermicro with LOM features are also available
95
IB Hardware Products (contd.)
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Customized adapters to work with IB switches
Cray XD1 (formerly by Octigabay), Cray CX1
Switches:
4X SDR and DDR (8-288 ports); 12X SDR (small sizes)
3456-port Magnum switch from SUN used at TACC
72-port nano magnum
36-port Mellanox InfiniScale IV QDR switch silicon in 2008
Up to 648-port QDR switch by Mellanox and SUN
Some internal ports are 96 Gbps (12X QDR)
IB switch silicon from Qlogic introduced at SC 08
Up to 846-port QDR switch by Qlogic
New FDR (56 Gbps) switch silicon (Bridge-X) has been announced by
Mellanox in May 11
Switch Routers with Gateways
IB-to-FC; IB-to-IPCCGrid '11 96
10G, 40G and 100G Ethernet Products
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10GE adapters: Intel, Myricom, Mellanox (ConnectX)
10GE/iWARP adapters: Chelsio, NetEffect (now owned by Intel)
40GE adapters: Mellanox ConnectX2-EN 40G
10GE switches
Fulcrum Microsystems
Low latency switch based on 24-port silicon
FM4000 switch with IP routing, and TCP/UDP support
Fujitsu, Myricom (512 ports), Force10, Cisco, Arista (formerly Arastra)
40GE and 100GE switches
Nortel Networks
10GE downlinks with 40GE and 100GE uplinks
Broadcom has announced 40GE switch in early 2010
CCGrid '11 97
Products Providing IB and HSE Convergence
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Mellanox ConnectX Adapter
Supports IB and HSE convergence
Ports can be configured to support IB or HSE
Support for VPI and RoCE
8 Gbps (SDR), 16Gbps (DDR) and 32Gbps (QDR) rates available
for IB
10GE rate available for RoCE
40GE rate for RoCE is expected to be available in near future
CCGrid '11 98
Software Convergence with OpenFabrics
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Open source organization (formerly OpenIB)
www.openfabrics.org
Incorporates both IB and iWARP in a unified manner
Support for Linux and Windows
Design of complete stack with `best of breed components Gen1
Gen2 (current focus)
Users can download the entire stack and run
Latest release is OFED 1.5.3
OFED 1.6 is underway
CCGrid '11 99
OpenFabrics Stack with Unified Verbs Interface
http://www.openfabrics.org/http://www.openfabrics.org/8/21/2019 Ccgrid11 Ib Hse Last
100/150
CCGrid '11
Verbs Interface(libibverbs)
Mellanox
(libmthca)
QLogic
(libipathverbs)
IBM
(libehca)
Chelsio
(libcxgb3)
Mellanox
(ib_mthca)
QLogic
(ib_ipath)
IBM
(ib_ehca)
Chelsio
(ib_cxgb3)
User Level
Kernel Level
Mellanox
Adapters
QLogic
Adapters
Chelsio
AdaptersIBM
Adapters
100
OpenFabrics on Convergent IB/HSE
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For IBoE and RoCE, the upper-level
stacks remain completelyunchanged
Within the hardware:
Transport and network layers remain
completely unchanged
Both IB and Ethernet (or CEE) link
layers are supported on the network
adapter
Note: The OpenFabrics stack is not
valid for the Ethernet path in VPI
That still uses sockets and TCP/IP
CCGrid '11
Verbs Interface(libibverbs)
ConnectX
(libmlx4)
ConnectX
(ib_mlx4)
User Level
Kernel Level
ConnectX
Adapters
HSE IB
101
OpenFabrics Software Stack
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CCGrid '11
SA Subnet Administrator
MAD Management Datagram
SMA Subnet Manager Agent
PMA Performance ManagerAgent
IPoIB IP over InfiniBand
SDP Sockets Direct Protocol
SRP SCSI RDMA Protocol(Initiator)
iSER iSCSI RDMA Protocol(Initiator)
RDS Reliable Datagram Service
UDAPL User Direct AccessProgramming Lib
HCA Host Channel Adapter
R-NIC RDMA NIC
Common
InfiniBand
iWARP
Key
InfiniBand HCA iWARP R-NIC
Hardware
Specific Driver
Hardware Specific
Driver
Connection
ManagerMAD
InfiniBand OpenFabrics Kernel Level Verbs / API iWARP R-NIC
SA
ClientConnection
Manager
Connection Manager
Abstraction (CMA)
InfiniBand OpenFabrics User Level Verbs / API iWARP R-NIC
SDPIPoIB SRP iSER RDS
SDP Lib
User Level
MAD API
OpenSMDiagTools
Hardware
Provider
Mid-Layer
Upper
LayerProtocol
User
APIs
Kernel Space
User Space
NFS-RDMARPC
ClusterFile Sys
Application
Level
SMA
Clustered
DB Access
Sockets
Based
Access
Various
MPIs
Access to
File
Systems
Block
Storage
Access
IP Based
App
Access
Apps &
Access
Methods
for using
OF Stack
UDAPL
Kernelbypass
Kernelbypass
102
InfiniBand in the Top500
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CCGrid '11 103
Percentage share of InfiniBand is steadily increasing
InfiniBand in the Top500 (Nov. 2010)
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45%
43%
6%
1%
0% 0% 1% 0% 0%0%
4%
Number of Systems
Gigabit Ethernet InfiniBand Proprietary
Myrinet Quadrics Mixed
NUMAlink SP Switch Cray Interconnect
Fat Tree Custom
CCGrid '11 104
25%
44%
21%
1%0%
0% 0%
0%
0%
0%
9%
Performance
Gigabit Ethernet Infiniband Proprietary
Myrinet Quadrics Mixed
NUMAlink SP Switch Cray Interconnect
Fat Tree Custom
InfiniBand System Efficiency in the Top500 List
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105CCGrid '11
0
10
20
30
40
50
60
70
80
90
100
0 50 100 150 200 250 300 350 400 450 500
Effici
ency(%)
Top 500 Systems
Computer Cluster Efficiency Comparison
IB-CPU IB-GPU/Cell GigE 10GigE IBM-BlueGene Cray
Large-scale InfiniBand Installations
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214 IB Clusters (42.8%) in the Nov 10 Top500 list (http://www.top500.org)
Installations in the Top 30 (13 systems):
CCGrid '11
120,640 cores (Nebulae) in China (3rd) 15,120 cores (Loewe) in Germany (22nd)
73,278 cores (Tsubame-2.0) at Japan (4th) 26,304 cores (Juropa) in Germany (23rd)
138,368 cores (Tera-100) at France (6th) 26,232 cores (Tachyonll) in South Korea (24th)
122,400 cores (RoadRunner) at LANL (7th) 23,040 cores (Jade) at GENCI (27th)
81,920 cores (Pleiades) at NASA Ames (11th) 33,120 cores (Mole-8.5) in China (28th)
42,440 cores (Red Sky) at Sandia (14th) More are getting installed !
62,976 cores (Ranger) at TACC (15th)
35,360 cores (Lomonosov) in Russia (17th)
106
HSE Scientific Computing Installations
http://www.top500.org/http://www.top500.org/8/21/2019 Ccgrid11 Ib Hse Last
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HSE compute systems with ranking in the Nov 2010 Top500 list
8,856-core installation in Purdue with ConnectX-EN 10GigE (#126)
7,944-core installation in Purdue with 10GigE Chelsio/iWARP (#147)
6,828-core installation in Germany (#166)
6,144-core installation in Germany (#214)
6,144-core installation in Germany (#215)
7,040-core installation at the Amazon EC2 Cluster (#231) 4,000-core installation at HHMI (#349)
Other small clusters
640-core installation in University of Heidelberg, Germany
512-core installation at Sandia National Laboratory (SNL) with
Chelsio/iWARP and Woven Systems switch
256-core installation at Argonne National Lab with Myri-10G
Integrated Systems
BG/P uses 10GE for I/O (ranks 9, 13, 16, and 34 in the Top 50)
CCGrid '11 107
Other HSE Installations
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HSE has most of its popularity in enterprise computing and
other non-scientific markets including Wide-areanetworking
Example Enterprise Computing Domains
Enterprise Datacenters (HP, Intel)
Animation firms (e.g., Universal Studios (The Hulk), 20th Century
Fox (Avatar), and many new movies using 10GE)
Amazons HPC cloud offering uses 10GE internally
Heavily used in financial markets (users are typically undisclosed)
Many Network-attached Storage devices come integrated
with 10GE network adapters
ESnet to install $62M 100GE infrastructure for US DOE
CCGrid '11 108
Presentation Overview
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Introduction
Why InfiniBand and High-speed Ethernet?
Overview of IB, HSE, their Convergence and Features
IB and HSE HW/SW Products and Installations
Sample Case Studies and Performance Numbers
Conclusions and Final Q&A
CCGrid '11 109
Modern Interconnects and Protocols
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110
Application
VerbsSocketsApplication
Interface
TCP/IP
Hardware
Offload
TCP/IP
Ethernet
Driver
Kernel
Space
Protocol
Implementation
1/10 GigE
Adapter
Ethernet
Switch
Network
Adapter
Network
Switch
1/10 GigE
InfiniBand
Adapter
InfiniBand
Switch
IPoIB
IPoIB
SDP
RDMAUser
space
IB Verbs
InfiniBand
Adapter
InfiniBand
Switch
SDP
InfiniBand
Adapter
InfiniBand
Switch
RDMA
10 GigE
Adapter
10 GigE
Switch
10 GigE-TOE
Case Studies
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Low-level Network Performance
Clusters with Message Passing Interface (MPI)
Datacenters with Sockets Direct Protocol (SDP) and TCP/IP
(IPoIB)
InfiniBand in WAN and Grid-FTP
Cloud Computing: Hadoop and Memcached
CCGrid '11 111
Low-level Latency Measurements
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CCGrid '11 112
0
5
10
15
20
25
30
VPI-IB
Native IBVPI-Eth
RoCE
Small Messages
Latency(us)
Message Size (bytes)
0
1000
2000
3000
4000
5000
6000
7000
8000
9000
10000Large Messages
Latency(us)
Message Size (bytes)
ConnectX-DDR: 2.4 GHz Quad-core (Nehalem) Intel with IB and 10GE switches
RoCE has a slight overhead compared to native IB because it operates at a slower clock rate (required to support
only a 10Gbps link for Ethernet, as compared to a 32Gbps link for IB)
Low-level Uni-directional Bandwidth Measurements
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CCGrid '11 113
0
200
400
600
800
1000
1200
1400
1600
VPI-IB
Native IB
VPI-Eth
RoCE
Uni-directional Bandwidth
Bandwid
th(MBps)
Message Size (bytes)
ConnectX-DDR: 2.4 GHz Quad-core (Nehalem) Intel with IB and 10GE switches
Case Studies
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Low-level Network Performance
Clusters with Message Passing Interface (MPI)
Datacenters with Sockets Direct Protocol (SDP) and TCP/IP
(IPoIB)
InfiniBand in WAN and Grid-FTP
Cloud Computing: Hadoop and Memcached
CCGrid '11 114
MVAPICH/MVAPICH2 Software
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High Performance MPI Library for IB and HSE
MVAPICH (MPI-1) and MVAPICH2 (MPI-2.2)
Used by more than 1,550 organizations in 60 countries
More than 66,000 downloads from OSU site directly
Empowering many TOP500 clusters
11th ranked 81,920-core cluster (Pleiades) at NASA
15th ranked 62,976-core cluster (Ranger) at TACC
Available with software stacks of many IB, HSE and server vendors
including Open Fabrics Enterprise Distribution (OFED) and Linux
Distros (RedHat and SuSE)
http://mvapich.cse.ohio-state.edu
CCGrid '11 115
One-way Latency: MPI over IB
http://mvapich.cse.ohio-state.edu/http://mvapich.cse.ohio-state.edu/http://mvapich.cse.ohio-state.edu/http://mvapich.cse.ohio-state.edu/8/21/2019 Ccgrid11 Ib Hse Last
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CCGrid '11 116
0
1
2
3
4
5
6Small Message Latency
Message Size (bytes)
Latency(us)
1.96
1.54
1.60
2.17
0
50
100
150
200
250
300
350
400
MVAPICH-Qlogic-DDR
MVAPICH-Qlogic-QDR-PCIe2
MVAPICH-ConnectX-DDR
MVAPICH-ConnectX-QDR-PCIe2
La
tency(us)
Message Size (bytes)
Large Message Latency
All numbers taken on 2.4 GHz Quad-core (Nehalem) Intel with IB switch
Bandwidth: MPI over IB
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CCGrid '11 117
0
500
1000
1500
2000
2500
3000
3500Unidirectional Bandwidth
MillionBytes/sec
Message Size (bytes)
2665.6
3023.7
1901.1
1553.2
0
1000
2000
3000
4000
5000
6000
7000
MVAPICH-Qlogic-DDRMVAPICH-Qlogic-QDR-PCIe2
MVAPICH-ConnectX-DDR
MVAPICH-ConnectX-QDR-PCIe2
Bidirectional Bandwidth
Mill
ionBytes/sec
Message Size (bytes)
2990.1
3244.1
3642.8
5835.7
All numbers taken on 2.4 GHz Quad-core (Nehalem) Intel with IB switch
One-way Latency: MPI over iWARP
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CCGrid '11 118
0
10
20
30
40
50
60
70
80
90
Chelsio (TCP/IP)
Chelsio (iWARP)
Intel-NetEffect (TCP/IP)
Intel-NetEffect (iWARP)
Message Size (bytes)
One-way Latency
Laten
cy(us)
25.43
2.4 GHz Quad-core Intel (Clovertown) with 10GE (Fulcrum) Switch
6.88
15.47
6.25
Bandwidth: MPI over iWARP
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CCGrid '11 119
0
200
400
600
800
1000
1200
1400
Message Size (bytes)
Unidirectional Bandwidth
Millio
nBytes/sec
839.8
1169.7
373.3
1245.0
0
500
1000
1500
2000
2500Chelsio (TCP/IP)
Chelsio (iWARP)
Intel-NetEffect (TCP/IP)
Intel-NetEffect (iWARP)
Message Size (bytes)
Million
Bytes/sec
Bidirectional Bandwidth
2260.8
855.3
2029.5
2.33 GHz Quad-core Intel (Clovertown) with 10GE (Fulcrum) Switch
647.1
Convergent Technologies: MPI Latency
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CCGrid '11 120
0
10
20
30
40
50
60Small Messages
La
tency(us)
Message Size (bytes)
0
2000
4000
6000
8000
10000
12000
14000
16000
18000
20000
Native IB
VPI-IB
VPI-Eth
RoCE
Large Messages
Latency(us)
Message Size (bytes)
ConnectX-DDR: 2.4 GHz Quad-core (Nehalem) Intel with IB and 10GE switches
37.65
3.62.21.8
Convergent Technologies:
MPI Uni- and Bi-directional Bandwidth
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CCGrid '11 121
MPI Uni- and Bi-directional Bandwidth
0
200
400
600
800
1000
1200
1400
1600
Native IB
VPI-IB
VPI-Eth
RoCE
Uni-directional Bandwidth
Bandwid
th(MBps)
Message Size (bytes)
0
500
1000
1500
2000
2500
3000
3500Bi-directional Bandwidth
Bandwid
th(MBps)
Message Size (bytes)
ConnectX-DDR: 2.4 GHz Quad-core (Nehalem) Intel with IB and 10GE switches
404.1
1115.7
1518.1
1518.1
1085.5
2114.9
2880.4
2825.6
Case Studies
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Low-level Network Performance
Clusters with Message Passing Interface (MPI)
Datacenters with Sockets Direct Protocol (SDP) and
TCP/IP (IPoIB)
InfiniBand in WAN and Grid-FTP
Cloud Computing: Hadoop and Memcached
CCGrid '11 122
IPoIB vs. SDP Architectural Models
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CCGrid '11 123
Traditional Model Possible SDP Model
Sockets App
Sockets API
Sockets Application
Sockets API
KernelTCP/IP Sockets
Provider
TCP/IP Transport
Driver
IPoIB Driver
User
InfiniBand CA
KernelTCP/IP Sockets
Provider
TCP/IP Transport
Driver
IPoIB Driver
User
InfiniBand CA
Sockets Direct
Protocol
Kernel
Bypass
RDMA
Semantics
SDP
OS Modules
InfiniBand
Hardware
(Source: InfiniBand Trade Association)
SDP vs. IPoIB (IB QDR)
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CCGrid '11 124
0
500
1000
1500
2000
2 8 32 128 512 2K 8K 32K
Bandwidth(M
Bps) IPoIB-RC
IPoIB-UD
SDP
0
5
10
15
20
25
30
2 4 8 16 32 64 128 256 512 1K 2K
Laten
cy(us)
0
500
1000
1500
2000
2500
3000
3500
4000
2 8 32 128 512 2K 8K 32K
BidirBandwidth(MBps)
SDP enables high bandwidth
(up to 15 Gbps),
low latency (6.6 s)
Case Studies
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Low-level Network Performance
Clusters with Message Passing Interface (MPI)
Datacenters with Sockets Direct Protocol (SDP) and TCP/IP
(IPoIB)
InfiniBand in WAN and Grid-FTP
Cloud Computing: Hadoop and Memcached
CCGrid '11 125
IB on the WAN
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Option 1: Layer-1 Optical networks
IB standard specifies link, network and transport layers Can use any layer-1 (though the standard says copper and optical)
Option 2: Link Layer Conversion Techniques
InfiniBand-to-Ethernet conversion at the link layer: switches
available from multiple companies (e.g., Obsidian)
Technically, its not conversion; its just tunneling (L2TP)
InfiniBands network layer is IPv6 compliant
CCGrid '11 126
UltraScience Net: Experimental Research Network Testbed
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Features
End-to-end guaranteed bandwidth channels
Dynamic, in-advance, reservation and provisioning of fractional/full lambdas
Secure control-plane for signaling
Peering with ESnet, National Science Foundation CHEETAH, and other networks
CCGrid '11 127
Since 2005
This and the following IB WAN slides are courtesy Dr. Nagi Rao (ORNL)
IB-WAN Connectivity with Obsidian Switches
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Supports SONET OC-192 or
10GE LAN-PHY/WAN-PHY
Idea is to make remote storage
appear local
IB-WAN switch does frameconversion
IB standard allows per-hop credit-
based flow control
IB-WAN switch uses large internalbuffers to allow enough credits to
fill the wire
CCGrid '11 128
CPU CPU
System
Controller
System
Memory
HCA
Host bus
StorageWide-area
SONET/10GE
IB switch IB WAN
InfiniBand Over SONET: Obsidian Longbows RDMA
throughput measurements over USN
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CCGrid '11 129
throughput measurements over USN
Linux
host
ORNL
700 miles
Linux
host
Chicago
CDCI
Seattle
CDCI
Sunnyvale
CDCIORNL
CDCI
longbow
IB/S
longbow
IB/S
3300 miles 4300 miles
ORNL loop -0.2 mile: 7.48Gbps
IB 4x: 8Gbps (full speed)
Host-to-host local switch:7.5Gbps
IB 4x
ORNL-Chicago loop 1400 miles: 7.47Gbps
ORNL- Chicago - Seattle loop 6600 miles: 7.37Gbps
ORNL Chicago Seattle - Sunnyvale loop 8600 miles: 7.34Gbps
OC192
Quad-core
Dual socket
Hosts:
Dual-socket Quad-core 2 GHz AMD
Opteron, 4GB memory, 8-lane PCI-
Express slot, Dual-port Voltaire 4x
SDR HCA
IB over 10GE LAN-PHY and WAN-PHY
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CCGrid '11 130
Linux
host
ORNL
700 miles
Linux
host
Seattle
CDCIORNL
CDCI
longbow
IB/S
longbow
IB/S
3300 miles 4300 miles
ORNL loop -0.2 mile: 7.5Gbps
IB 4x
ORNL-Chicago loop 1400 miles: 7.49Gbps
ORNL- Chicago - Seattle loop 6600 miles: 7.39Gbps
ORNL Chicago Seattle - Sunnyvale loop 8600 miles: 7.36Gbps
OC192
Quad-core
Dual socket
Chicago
CDCI
ChicagoE300
Sunnyvale
E300
Sunnyvale
CDCI
OC 192
10GE WAN PHY
MPI over IB-WAN: Obsidian Routers
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Delay (us) Distance
(km)
10 2
100 20
1000 200
10000 2000
Cluster A Cluster BWAN Link
Obsidian WAN Router Obsidian WAN Router
(Variable Delay) (Variable Delay)
MPI Bidirectional Bandwidth Impact of Encryption on Message Rate (Delay 0 ms)
Hardware encryption has no impact on performance for less communicating streams
131CCGrid '11
S. Narravula, H. Subramoni, P. Lai, R. Noronha and D. K. Panda, Performance of HPC Middleware over
InfiniBand WAN, Int'l Conference on Parallel Processing (ICPP '08), September 2008.
Communication Options in Grid
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Multiple options exist to perform data transfer on Grid Globus-XIO framework currently does not support IB natively We create the Globus-XIO ADTS driver and add native IB support
to GridFTP
Globus XIO Framework
GridFTP High Performance Computing Applications
10 GigE Network
IB Verbs IPoIB RoCE TCP/IP
Obsidian
Routers
132
CCGrid '11
Globus-XIO Framework with ADTS Driver
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Globus XIO Driver #n
DataConnection
Management
PersistentSession
Management
Buffer &File
Management
Data Transport Interface
InfiniBand / RoCE 10GigE/iWARP
Globus XIOInterface
File System
User
Globus-XIOADTS Driver
Modern WANInterconnects Network
Flow ControlZero Copy Channel
Memory Registration
Globus XIO Driver #1
133CCGrid '11
Performance of Memory Based
Data Transfer
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134
Data Transfer
Performance numbers obtained while transferring 128 GB ofaggregate data in chunks of 256 MB files
ADTS based implementation is able to saturate the linkbandwidth
Best performance for ADTS obtained when performing datatransfer with a network buffer of size 32 MB
0
200
400
600
800
10001200
0 10 100 1000
Bandwidth(MBps)
Network Delay (us)
ADTS Driver
2 MB 8 MB 32 MB 64 MB
0
200
400
600
800
10001200
0 10 100 1000
Bandwidth(MBps)
Network Delay (us)
UDT Driver
2 MB 8 MB 32 MB 64 MB
CCGrid '11
Performance of Disk Based Data Transfer
A h M d
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135
Performance numbers obtained while transferring 128 GB ofaggregate data in chunks of 256 MB files
Predictable as well as better performance when Disk-IOthreads assist network thread (Asynchronous Mode)
Best performance for ADTS obtained with a circular bufferwith individual buffers of size 64 MB
0
100
200
300
400
0 10 100 1000
Bandwidth(MBps)
Network Delay (us)
Synchronous Mode
ADTS-8MB ADTS-16MB ADTS-32MB
ADTS-64MB IPoIB-64MB
0
100
200
300
400
0 10 100 1000
Bandwidth(M
Bps)
Network Delay (us)
Asynchronous Mode
ADTS-8MB ADTS-16MB ADTS-32MB
ADTS-64MB IPoIB-64MB
CCGrid '11
Application Level Performance
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136
0
50
100
150
200
250
300
CCSM Ultra-Viz
Bandwidth(MBps)
Target Applications
ADTS IPoIB
Application performance for FTP get
operation for disk based transfers Community Climate System Model(CCSM)
Part of Earth System Grid Project Transfers 160 TB of total data inchunks of 256 MB
Network latency - 30 ms Ultra-Scale Visualization (Ultra-Viz)
Transfers files of size 2.6 GB Network latency - 80 ms
The ADTS driver out performs the UDT driver using IPoIB by more than100%
H. Subramoni, P. Lai, R. Kettimuthu and D. K. Panda, High Performance Data Transfer inGrid Environment Using GridFTP over InfiniBand, Int'l Symposium on Cluster Computing andthe Grid (CCGrid), May 2010.
136CCGrid '11
Case Studies
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Low-level Network Performance
Clusters with Message Passing Interface (MPI)
Datacenters with Sockets Direct Protocol (SDP) and TCP/IP
(IPoIB)
InfiniBand in WAN and Grid-FTP
Cloud Computing: Hadoop and Memcached
CCGrid '11 137
A New Approach towards OFA in Cloud
Current ApproachCurrent Cloud Our Approach
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pp
Towards OFA in Cloud
Application
Accelerated Sockets
10 GigE or InfiniBand
Verbs / Hardware
Offload
Software Design
Application
Sockets
1/10 GigE
Network
pp
Towards OFA in Cloud
Application
Verbs Interface
10 GigE or InfiniBand
Sockets not designed for high-performance
Stream semantics often mismatch for upper layers (Memcached, Hadoop)
Zero-copy not available for non-blocking sockets (Memcached)
Significant consolidation in cloud system software
Hadoop and Memcached are developer facing APIs, not sockets
Improving Hadoop and Memcached will benefit many applications immediately!
CCGrid '11 138
Memcached Design Using Verbs
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Server and client perform a negotiation protocol
Master thread assigns clients to appropriate worker thread
Once a client is assigned a verbs worker thread, it can communicate directlyand is bound to that thread
All other Memcached data structures are shared among RDMA and Socketsworker threads
SocketsClient
RDMA
Client
MasterThread
Sockets
Worker
Thread
Verbs
WorkerThread
Sockets
Worker
Thread
Verbs
WorkerThread
Shared
Data
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