Technology Trends: The Datacenter is the Computer, The Cellphone/Laptop is the Computer

1. 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

2. 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?

3. 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 Standard 1983 10 Mbit/s IEEE 802.3 1995 100 Mbit/s IEEE 802.3u 1999 1000 Mbit/s IEEE 802.3ab • 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?

4. Technology Trends: Internet • Datacenters: new Internet backbone • Huge concentration of bandwidth & computation • Shift in traffic pattern • More and more traffic is hostDatacenter • Huge data transfers between/within DCs are the norm • Note: IP alone not designed for such networks

5. 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

6. 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?)

7. 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?

8. A Parallel Revolution Par Lab • 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; actuallya 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

9. 100+ Cores? Par Lab 80x86 Uniprocessors No longer sold • 5-year research program aim 8+ years out • Multicore: 2X / 2 yrs  ≈ 64 cores in 8 years • Manycore: 8X multicore 16-way MP laptopsfor sale in 2011

10. Revolution May Fail Par Lab • 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?

11. Re-inventing Client/Server Par Lab • “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 • Laptop/Handheld as future client, Datacenter as future server

12. Trends Summary Par Lab • 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?