1 testbeds les cottrell site visit to slac by doe program managers thomas ndousse & mary anne...
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1
Testbeds
Les Cottrell
Site visit to SLAC by DoE program managers Thomas Ndousse & Mary Anne Scott
April 27, 2005
www.slac.stanford.edu/grp/scs/net/talk05/testbeds-apr05.ppt
Partially funded by DOE/MICS Field Work Proposal on Internet End-to-end Performance
Monitoring (IEPM)
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UL Testbed 10Gbits/s• Sunnyvale (interim until get ESnet 10Gbps circuits to
SLAC, July 2005):– Currently UltraLIght– Cisco 6509 from UltraLight proposal– Four Sun v20z 1.8GHz Opterons loaned from BaBar– 10GE TOE NICs loaned from Chelsio– 4 10GE Neterion(S2io) 10GE NICs purchased
• Installed with Solaris-10 and Linux 2.6– Will get file server from Caltech– Remote management
• Purchased/installed terminal server to provide console access• Purchased/installed remote power management
– Connect Cisco to 10Gbps UltraLight circuit– Interim USN IP connection imminent
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Sunnyvale set up• Hosts have Solaris 1-, Linux 2.6, Neterio &
Chelsio 10GE NICs
.5
.3.6
A3
A4
A5
A6
A2
.8
.7
.4
Power
Console
10Gbits/s UltraLight (192.84.86.x)
CENIChttp://137.164.37.3 power management
UltraLight
10Mbps management(134.164.37.x)
.18
.19
TerminalServer
Hub
Compute servers
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Approaching 10Gbps performance
• Jumbo frames (1500Bytes std => 9000Bytes), factor of 6 improvement in recovery rate– Not an IEEE standard– May break some UDP applications– Not supported on many LANs
• Sender mods only, HENP model is few big senders, lots of smaller receivers– Simplifies deployment, only a few hosts at a few sending
sites– So no Dynamic Right Sizing (DRS) at receiver
• XCP/ECN needs router mods so hard to deploy a new Internet
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Hardware Assists• For 1Gbits/s paths, cpu, bus etc. not a problem• For 10Gbits/s they are important• NIC assistance to the CPU is becoming popular
– Checksum offload– Interrupt coalescence– Large send/receive offload (LSO/LRO)– TCP Offload Engine (TOE)
• Several vendors for 10Gbits/s NICs, at least one for 1Gbits/s NIC
• But currently restricts to using NIC vendor’s TCP implementation
• Most focus is on the LAN– Cheap alternative to Infiniband, MyriNet etc.
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10Gbps test• Sunfire vx0z, Linux & Solaris 10, Chelsio &
Neterion• Back-to-back (LAN) testing at SLAC• SNV to LA• At SC2004 using two 10Gbps dedicated paths
between Pittsburgh and Sunnyvale– Using Solaris 10 (build 69) and Linux 2.6– On Sunfire Vx0z (dual & quad 2.4GHz 64 bit AMD Opterons)
with PCI-X 133MHz 64 bit– Only 1500 Byte MTUs
• Achievable performance limits (using iperf)– TOE (Chelsio) vs no TOE (Neterion(S2io))– LSO vs no LSO support– Solaris 10 vs Linux
• UDTv2 evaluation
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CPU Utilization• Receiver needs 20% less CPU than sender
for high throughputCPU utilization vs throughput,
SLAC to CENIC-LA
y = 18.116xR2 = 0.9972
y = 14xR2 = 0.9782
0
20
40
60
80
100
120
0 1 2 3 4 5 6
Achievable throughput (Mbits/s)
% C
PU
Uti
lizat
ion
Receiver % cpuSender % cpuLinear (Sender % cpu)Linear (Receiver % cpu)
MTU: 9000BytesStreams 1v20z dual 1.8GHz OpteronS2io/Neterion
Sender+LSO
Receiver+LSO
For Neterion with LSO & Linux: Sender appears to use more CPU than receiver as the throughput increases
• Single stream limited by 1.8GHz CPU
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Effect of Jumbos• Throughput SLAC-CENIC LA (1 stream, 2MB
window with LSO Neterion(S2io)/Linux):– 1500B MTU 1.8 Gbps – 9000B MTU 6 Gbps
• Sender CPU: GHz/Gbps (single stream with LSO Neterion/Linux): – 1500B MTU = 0.5 ± 0.13 GHz/Gbps– 9000B MTU = 0.3 ± 0.07 GHz/Gbps– Factor 1.7 improvement
For Neterion with LSO &Linux on WAN, Jumbos have a huge effect on performance and also improve CPU utilization
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Effect of LSO• v20z 1.8GHz, Linux 2.6,
S2io, 2 streams SLAC to Caltech, 8MB window:– With LSO: 7.4Gbits/s, – Without LSO: 5.4Gbits/s,
• LAN (3 streams, 164KB window)– Solaris => Linux: 6.4Gbps (No
LSO support in Solaris 10 at the moment)
– Linux => Solaris-10: 4.8Gbps (LSO turned off sender)
– Linux => Solaris-10: 7.54Gbps (LSO turned on)
CPU Utilization vs throughput, SNV to CalTech
y = 0.1727xR2 = 0.9975
y = 0.2343xR2 = 0.9934
0%
20%
40%
60%
80%
100%
120%
0 2 4 6 8
Achievable throughput (Gbits/s)
% C
PU
uti
lizat
ion
MTU: 9000BStreams: 1txqueuelen: 1000
Ratio (1500B/9000B)~1.4
with LSO
without LSO
For Neterion with Linux on LAN LSO improves CPU utilization by a factor of 1.4. If one is CPU limited this will also improve throughput.
1 stream
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Solaris vs Linux• Send from one to the other single stream• Compare send from Linux Neterion + LSO with send
from Solaris 10 without LSO– LSO support for Solaris coming soon
Achievable throughput vs Window size on LAN 1 stream
0
1
2
3
4
5
6
7
0 20 40 60Window (MB)
Th
rou
gh
pu
t (G
bit
s/s
) Linux to SolarisSolaris to Linux
MTU: 9400BMedian Linux: 5.9 GbpsMedian Solaris: 6.2 Gbps
• With one stream Solaris sender sends faster
• Sol slightly better GHz/Gbps GHz/Gbps: Solaris 0.287+-0.001; Linux 0.303+-0.001
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Solaris vs Linux multi-
streamsWhen optimize for
multiple streams, Linux + LSO sender is better
Achievable throughput vs streams and window
0
1
2
3
4
5
6
7
8
0 5 10 15 20Streams
Th
rou
gh
pu
t (G
bit
s/s)
Solaris
Linux
1MB
2MB
4MB
• Solaris without LSO performs poorly with multiple streams (LSO or OS related?)– Its GHz/Gbps is poorer than Linux+LSO
for multiple streams
LANMTU: 9400BS2io
7.5Gbps
6.4Gbps
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Chelsio• Chelsio to Chelsio (TOE)• With 2.4GHz V20zs from Pittsburgh to SNV• 1500Byte MTUs• Reliably able to get 7.4-7.5 Gbps (16 streams)• GHz/Gbps Chelsio(MTU=1500B) ~ Neterion (9000B)
Chelsio(TOE)
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SLAC Connection• Part of ESnet Bay Area MAN
– Will be 4 * 10GE circuits, 2 in 2 out for ring– QWest will connect to Stanford in next fortnight– Then cross-connect to SLAC/Stanford fibers and
thus to SLAC• Working with Stanford to ID fiber pairs
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Joint Caltech, SLAC, Joint Caltech, SLAC, FNAL, CERN, UF, FNAL, CERN, UF, SDSC, BR, KR, ….SDSC, BR, KR, ….
10 10 Gbps waves to 10 10 Gbps waves to HEP on show floorHEP on show floor
Bandwidth challenge: Bandwidth challenge: aggregate throughput aggregate throughput of 101.13 Gbpsof 101.13 Gbps
FAST TCPFAST TCP
SC2004: Tenth of a Terabit/s Challenge
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Bandwidth Challenge
Large collaboration of academia and industryTook a lot of “wizards” to make it work
>100 Gbps aggregate
The prize!
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Conclusions• UDT limit was ~ 4.45Gbits/s
– Cpu limited
• TCP Limit was about 7.5±0.07 Gbps, regardless of:– Whether LAN (back to back) or WAN
• TCP Gating factor=PCI-X 133Mhz ≡ 7.5Gbps• One host with 4 cpus & 2 NICs sent
11.5±0.2Gbps to two dual cpu hosts with 1 NIC each
• Two hosts to two hosts (1 NIC/host) on one 10Gbps link 9.07Gbps goodput forward & 5.6Gbps reverse
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Conclusions• Jumbos can be a big help
• LSO is helpful (Neterion)
• For best throughput Linux+LSO sender better
• Without LSO Solaris provides more throughput
• Solaris without LSO has problems with multiple streams
• TOE (Chelsio) allows one to avoid 9000Byte MTUs
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Conclusions• Need testing on real networks
– Controlled simulation & emulation critical for understanding
– BUT need to verify, and results can look different than expected
• Needs honest independent broker (SLAC)– Don’t care who wins, have the contacts, reputation,
testbeds etc.– Not really funded for this
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Next Steps• Evaluate various offloads (TOE, LSO, LRO ...),
• Evaluate OS support: Solaris 10 support of LSO, untangle Solaris Linux, Chelsio/TOE on Solaris, leverage industry contacts
• New buses: PCI-X 266Mhz and PCI-Express important, need NICs/hosts to support then evaluate
• Install IEPM-BW on 10Gbps testbed– Evaluate existing tools at 10Gbits/s– Explore new tools for 10Gbits/s
• Exploit relationships with Neterion/Chelsio to work with packet pair timing aided by NICs
• Install Passive tools (on 10Gbps testbeds and work with BNL to help achieve mission))– Evaluate Netflow measurement & analysis at 10Gbits/s
• Privacy issues
– Use SNMP to access MIBs utilization etc.
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Acknowledgements• Gary Buhrmaster*, Parakram Khandpur*, Harvey
Newmanc, Yang Xiac, Xun Suc, Dan Naec,Sylvain Ravotc, Richard Hughes-Jonesm, Michael Chen+, Larry McIntoshs, Frank Leerss, Leonid Grossmann, Alex Aizmann
• SLAC*, Caltechc, Manchester Universitym, Chelsio+, Suns, Neterion(S2io)n
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Further Information• Web site with lots of plots & analysis
– www.slac.stanford.edu/grp/scs/net/papers/pfld05/ruchig/Fairness/
• Inter-protocols comparison (Journal of Grid Comp, PFLD04)– www.slac.stanford.edu/cgi-wrap/getdoc/slac-pub-10402.pdf
• SC2004 details– www-iepm.slac.stanford.edu/monitoring/bulk/sc2004/
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FromLSOff
MTUBytes
Median ThruGbps IQR
GHz/Gbps IQR
Linux On 9400 7.395 0.0150.41
6 0.015
Linux On 1500 2.03 0.10.27
5 0.073
Linux Off 9400 4.75 0.0550.37
5 0.006
Solaris Off 9400 6.2 0.020.28
7 0.001
Solaris Off 1500 1.3 0.415 0.59 0.115
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When will it have an impact
• ESnet traffic doubling/year since 1990• SLAC capacity increasing by 90%/year
since 1982– SLAC Internet traffic increased by factor 2.5
in last year• International throughput increase by factor
10 in 4 years• So traffic increases by factor 10 in 3.5 to 4
years, so in:– 3.5 to 5 years 622 Mbps => 10Gbps– 3-4 years 155 Mbps => 1Gbps– 3.5-5 years 45Mbps => 622Mbps
• 2010-2012:– 100s Gbits for high speed production net
end connections – 10Gbps will be mundane for R&E and
business– Home broadband: doubling ~ every year,
100Mbits/s by end of decade– Aggressive Goal: 1Gbps to all Californians
by 2010
Thr
ough
put M
bits
/s Throughput from US
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What was special? • End-to-end application-to-application, single and multi-
streams (not just internal backbone aggregate speeds)• TCP has not run out of stream yet, scales from modem
speeds into multi-Gbits/s region– TCP well understood, mature, many good features: reliability etc.– Friendly on shared networks
• New TCP stacks only need to be deployed at sender– Often just a few data sources, many destinations– No modifications to backbone routers etc– No need for jumbo frames
• Used Commercial Off The Shelf (COTS) hardware and software
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What was Special 2/2
• Raise the bar on expectations for applications and users– Some applications can use Internet backbone
speeds– Provide planning information
• The network is looking less like a bottleneck and more like a catalyst/enabler– Reduce need to colocate data and cpu– No longer ship literally truck or plane loads of data
around the world– Worldwide collaborations of people working with
large amounts of data become increasingly possible
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Who needs it?
• HENP – current driver– Multi-hundreds Mbits/s and Multi TByte files/day transferred across
Atlantic today• SLAC BaBar experiment already has a PByte stored
– Tbits/s and ExaBytes (1018) stored in a decade
• Data intensive science:– Astrophysics, Global weather, Bioinformatics, Fusion, seismology…
• Industries such as aerospace, medicine, security …• Future:
– Media distribution• Gbits/s=2 full length DVD movies/minute
• 100 Gbits/s is equivalent to – Download Library of Congress in < 14 minutes– Three full length DVDs in a second
• Will sharing movies be like sharing music today?