The Datacenter is the Computer

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The Datacenter is the Computer

• David Patterson Director, RAD LabJanuary, 2007

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Technology Trends CPU

• Microprocessor Power Wall Memory Wall ILP
  Wall Brick Wall
• ? End of uniprocessors and faster clock rates
• Since parallel more power efficient (W
  CV2F)New Moores Law is 2X processors or
  cores per socket every 2 years, same clock
  frequency
• Conservative 2007 4 cores, 2009 8 cores, 2011
  16 cores for embedded, desktop, server
• Sea change for HW and SW industries since
  changing programmer model, responsibilities
• Every program(mer) is a parallel program(mer),
  Sequential algorithms are slow algorithms

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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 (1 GB
  DIMM)
• 2X capacity every 3 years? (vs. 4X/3yrs in 1990s)
• DRAM performance only BW improvements (DDR-2,
  DDR-3), little latency improvement
• 64-bit Addresses Multiple cores/socket ?
  Majority number of chips DRAM vs. Logic?
  Majority of system cost DRAM vs. Logic
• ? Majority of power is DRAM vs. Logic
• Shift in chips, cost, power to DRAM from CPU
  increases over time

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Technology Trends Disk

• Disk After capacity 100 per year 96 - 03,
  slowdown to 30 per year recently (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
• 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, as
  3X too expensive in cost ( power)?

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Technology Trends Flash
2007 SATA SCSI Flash DRAM
GB/ 3.33 0.50 0.08 0.01
IOPS/GB 0.2 4 200 5,000,000
GB/Watt 50 5 100 0.5

• Flash Memory is credible threat to small disks
• Modular, 1000X latency, BW, lt power, but 1M
  writes
• Camera, Ipod industry funds flash RD
• 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?

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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 over 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?

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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 host?Datacenter
• Huge data transfers between/within DCs are the
  norm
• Note IP alone not designed for such networks

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Technology Trends OS

• Resurgence of popularity in virtual machines
• Traditional OSes too large and brittle
• VM monitor thin SW layer btw guest OS and HW
• Advantages
• Security, Dependability via isolation
• VMs move from failing processor
• Rosenblum future of OSs could be libraries
  where only functions needed linked into app, on
  top of thin VMM layer provides protection,
  sharing of resources
• SW shipped with OS features VM reader?

The Impact of Virtualization on Computer
Architecture and Operating Systems,
Keynote Address, ASPLOS XII, Oct. 23, 2006