A Proposal to Introduce Power and Energy Notions in Computer Architecture Laboratories

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A Proposal to Introduce Power and Energy Notions
in Computer Architecture Laboratories

• Alicia Asín, Darío Suárez, Víctor Viñals
• gaZ DIIS I3A
• Universidad de Zaragoza
• HiPEAC Network of Excellence

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Power Major Issue in Computer Architecture
Nuclear reactor
W / cm2
Pentium 4
Pentium II
Core DUO
Pentium III
Pentium
i486
Pentium Pro
i386
Adapted from Pollack (MICRO99)
Technology from older to newer (µm)
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How to Introduce Energy and Power in Computer
Architecture courses

• Students will get insights in energy and power

Hardware-based laboratories
Challenging experiments
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Summary

• Motivation
• Goals and requirements
• Platform description
• Energy breakdown in an Intel Pentium 4
• Conclusions

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Goals

• Do not alter Computer Architecture course
  syllabus
• Platform for both education and research
• Obtain the static consumption in a standard
  processor

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Requirements

• Low-cost, reuse resources from the department
• Use real hardware
• Sort platform time training

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Summary

• Motivation
• Goals and requirements
• Platform description
• Energy breakdown in an Intel Pentium 4
• Conclusions

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Platform view
Liquid refrigeration system
PC under test
Monitoring PC
Clamp meter
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Platform Schematic

• Measurements without hacking the motherboard

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Platform Description

• PC under test

• Monitoring PC

• Intel Pentium 4
• GNU/Linux
• Performance Application Programming Interface,
  PAPI, (Dongarra et. al., 2001)
• Bare system

• In-house tool
• Labview
• Widely used, compatible with a lot of data
  acquisition cards
• Sort time of application development
• Final application very easy to use

Frequency scaling
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Application screenshot

• live measurements store acquired data

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Summary

• Motivation
• Goals and requirements
• Platform description
• Energy breakdown in an Intel Pentium 4
• Conclusions

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Intel Pentium 4 Energy Breakdown

• Static consumption has emerged as a mayor issue
  in power-aware architectures
• Information not available in datasheets

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Dynamic and Static power

• Dynamic

• Static

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Decomposition of the consumption (Sinha et. al.,
2003)
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Assertion verification

• Ensure CPI does not vary
• Benchmark choice, LU factorization
• Small footprint, low cache miss rate
• Hardware counters
• Keep temperature under control
• Liquid refrigeration system

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Measured Results

• Model fits well with the data

Pentium 4 in 130 nm, Vdd 1.6 V Static power
estimation 35.94 W Leakage current
estimation 22.46 A
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Energy and Average Power

• Total energy

• Average Power

Dynamic energy remains constant
Static power remains constant
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Summary

• Motivation
• Goals and requirements
• Platform description
• Energy breakdown in an Intel Pentium 4
• Conclusions

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Conclusions and future work

• Low-cost platform able to measure and store the
  processor consumption
• Platform enables to carry out interesting
  laboratories, valid also for research. E.g.,
  dynamic and static energy decomposition
• Aimed to introduce the laboratory in main
  computer architecture courses taught at the
  University of Zaragoza

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A Proposal to Introduce Power and Energy Notions
in Computer Architecture Laboratories

• Alicia Asín, Darío Suárez, Víctor Viñals
• a.asin_at_libelium.com, dario, victor_at_unizar.es
• http//webdiis.unizar.es/gaz/

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Benchmark

• LU factorization
• Small footprint
• Matrixes 20x20
• 1M iterations

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Platform Hardware Requirements

• Hardware counters
• Measurements without modifying the motherboard
• Temperature measurements
• Change the frequency without reboot

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Platform Software Requirements

• View live measurements
• Change the frequency without rebooting
• Store the acquired data
• Process control in the computer under test