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UC Berkeley

Par Lab

Technology Trends: The Datacenter is the Computer,

The Cellphone/Laptop is the Computer

David Patterson Director, Reliable Adaptive Distributed Lab

Director, Parallel Computing Lab

Past President, ACMOctober, 2007

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Outline

LAN: 10X BW / link / 4-5 years Internet: Data Centers = new Internet backbone DRAM: 2X size / chip / 3 years, = latency, > BW

Larger % chips, % power, % $ of systems Flash: Threat to (small) disks? Disk: 2X size / disk / 3 years , = latency, > BW CPU: 2X cores / chip / 2 years,

≤ clock rate, = power Cell phone/Laptop and Datacenter: Ends of

spectrum most interesting platforms of future?

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Technology Trends: LAN

• Ethernet: from shared media to switch and twisted pair shortens time to new generation

– But shorter distance per link using copper

• Year of Standard1983 10 Mbit/s IEEE 802.31995 100 Mbit/s IEEE 802.3u1999 1000 Mbit/s IEEE 802.3ab2003 10000 Mbit/s IEEE 802.3ac (optical)2006 10000 Mbit/s IEEE 802.3an (copper)

• Expect 10 Gbit/s economical in 2007• 100 Gbit/sec IEEE standard started 2006

– Standard in 2008? Economical in 2012?

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Technology Trends: Internet

• Datacenters: new Internet backbone– Huge concentration of bandwidth & computation – Shift in traffic pattern

• More and more traffic is hostDatacenter• Huge data transfers between/within DCs are the norm

• Note: IP alone not designed for such networks

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Technology Trends: DRAM

• DRAM capacity: decelerate capacity per chip due in part to 32-bit address limit, investments– 512 Mbit sold in 2002; still dominates as of Jan 07– 2X capacity every 3 years? (vs. 4X/3yrs in 1990s)– DRAM performance: only BW improvements (DDR-2,

DDR-3), little latency improvement, power worse

• 64-bit Addresses + Multiple cores/socket Majority % chips DRAM vs. Logic Majority % of power is DRAM vs. Logic Majority % of system $ DRAM vs. Logic

• Shift in % chips, power, $ to DRAM from CPU and % increases over time

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Technology Trends: Disk• Disk: After capacity 100% per year ‘96 - ‘03,

slowdown recently: 30%? 50%? (1TB in 07)– Consolidation of industry, lack of demand by PCs– Home Video restart PC demand, capacity wars?

• Split: ATA best GB/$, SCSI best performance/$– Reliability close (see 2007 Google and CMU papers)

• Performance: Interface switch from parallel to serial: Serial ATA (SATA), Serial SCSI (SAS) Low Cost Disk arrays

• Disk performance: latency slow change, bandwidth improves, but not as fast as capacity Takes longer to read whole disk (3 hours) Takes longer repair Must handle 2 faults RAID 6 or 3X replication (power, space?)

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Technology Trends: Flash

• Flash Memory is credible threat to small disks – Modular, 1000X latency, ≈ BW, < power, but 1M writes

• Camera, Ipod industry funds flash R&D– Flash Improvement Rate: 2X GB/$ every 9 months?

• IF disk and flash rates continue, flash matches GB/$ SCSI in 2009, GB/$ SATA in 2012

• Future: Phase-change RAM (PRAM); ≈ no write limit, write 30X faster, archival; Samsung 2008?

2007 SATA SCSI Flash DRAMGB/$ 3.33 0.50 0.08 0.01

IOPS/GB 0.2 4 200 5,000,000

GB/Watt 50 5 100 0.5

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A Parallel Revolution• PC, Server: Power Wall + Memory Wall = Brick Wall

End of way built microprocessors for last 40 years New Moore’s Law is 2X processors (“cores”) per

chip every technology generation (≈ 2 years), but same (or slower) clock rate and simpler CPUs– Conservative plan: 2007 4 cores/chip, 2009 8 cores,

2011 16 cores, … for laptop & server & embedded– “This shift toward increasing parallelism is not a triumphant

stride forward based on breakthroughs; actually a retreat from even greater challenges that thwart efficient silicon implementation of traditional solutions.” The Parallel Computing Landscape: A Berkeley View, Dec 2006

• Sea change for HW & SW industries since changing the model of programming and debugging

• Every program(mer) is a parallel program(mer),Sequential algorithms are slow algorithms

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100+ Cores?

• 5-year research program aim 8+ years out• Multicore: 2X / 2 yrs ≈ 64 cores in 8 years• Manycore: 8X multicore

Par Lab

80x86UniprocessorsNo longer sold

16-way MP laptopsfor sale in 2011

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1985 1995 2005 2015

Millions of PCs / year

Revolution May Fail• John Hennessy, President, Stanford University, 1/07:

“…when we start talking about parallelism and ease of use of truly parallel computers, we're talking about a problem that's as hard as any that computer science has faced. … I would be panicked if I were in industry.”

“A Conversation with Hennessy & Patterson,” ACM Queue Magazine, 4:10, 1/07.

• 100% failure rate of Parallel Computer Companies – Convex, Encore, MasPar, NCUBE, Kendall Square Research,

Sequent, (Silicon Graphics), Transputer, Thinking Machines, …

• What if IT goes from a growth industry to areplacement industry?– If SW can’t effectively use

8, 16, 32, ... cores per chip SW no faster on new computer Only buy if computer wears out

• Accelerate trend to SaaS?

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Re-inventing Client/Server

Laptop/Handheld as future client, Datacenter as future server

“The Datacenter is the Computer” Building sized computers: Google, MS, …

“The Laptop/Handheld is the Computer” 2007: HP sales laptops > desktops 1B+ Cell phones/yr, increasing in function Apple iPhone raises the bar for quality and business for cellphones

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Trends Summary CPU: 2X cores / chip / 2 years,

≤ clock rate, = power (La-Z-boy programmer era is over)

DRAM: 2X size / chip / 3 years, = latency, > BW Larger % chips, % power, % $ of systems

Flash: Threat to (small) disks? Disk: 2X size / disk / 3 years , = latency, > BW LAN: 10X BW / link / 4-5 years Internet: Data Centers = new Internet backbone Cell phone/Laptop and Datacenter: Ends of spectrum most interesting platforms of future?

Par Lab