Energy Dumpster Diving
- Example presentation-
Paper written by:
M. A. Kazandjieva, B. Heller, P. Levis, C. Kozyrakis
In Proceedings of HotPower 2009, USA
Presented by:
Simin Nadjm-Tehrani / Ekhiotz Vergara /
Jalil Boudjadar / Antonia Arvanitaki
Department of Computer and Information Science (IDA)
Linköping University, Sweden
January 25, 2016
Introduction
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Large computing systems
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PowerNet sensing infrastructure
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Individual elements contribute to consumption
Sources of waste difficult to identify
Power consumption of individual devices
Correlation with usage information
Analysis of consumption
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Reveal device inefficiencies
Usage scenarios that waste energy
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PowerNet
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Large-scale distributed sensing infrastructure
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Provides
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Per-device energy measures
Usage statistics
Deployed in real office building environment
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PowerNet deployment
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Stanford Computer Science building
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Office environment
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Data center server rack
Small networking closet
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Desktops
Monitors
Network switches
Some numbers
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85 power meters
Utilisation data collected
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15 desktops
10 servers
5 switches
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PowerNet components
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Wired power meters
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Watt's Up .NET with
Ethernet interface
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Disadvantages:
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Requires Ethernet port
Difficult to configure
Relatively high power
consumption – 3 W
Low sampling rate – 1 Hz
High monetary cost
Similar model shown here
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Wireless power meter
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Implemented as a customised mote
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Low power processor (1mA active, 1uA sleep)
Digital power meter chip
Characteristics
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High rate of sampling – 14KHz
Configurable – TinyOS
No wired network required – mesh network
Lower monetary cost
Mote: resource-constrained
device that can sense, process,
and talk wirelessly to other motes
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Mesh network
Computer
or server
Gateway
Sink
Motes
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Motes can talk to each other without cables
Data is forwarded to the sink
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Mote or computer that gathers data forwarded
Sink is wired to a gateway
Gateway provides out-of-network connectivity
Image from: The Basics of Wireless Sensor Networking and its Applications
http://www.ida.liu.se/~rtslab/courses/wsn/Basics.pdf
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Utilisation metering
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PowerNet monitors device usage
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Desktops and servers
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Network switches
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CPU utilisation
Python script tracks utilisation
Traffic statistics for each port
Monitor hardware counters via SNMP
Server rack
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Balanced workload
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Data management and visualisation
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Data stored in a central server
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Power and utilisation data correlated
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Kept in a MySQL database
Data synchronised in time using timestamps
Analysis of consumption related to activity
Data visualisation through website
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Line-chart visualisation of all data
Correlated power and utilisation graphs
Searches by meter name, type, or device category
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Case study: Desktops
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High idle energy consumption (100 W)
Reduction
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Put desktops in sleep mode when not used
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User and CPU must be inactive
All graphs: Maria Kazandjieva, Brandon Heller, Philip Levis, and Christos Kozyrakis.
Energy Dumpster Diving. In Second Workshop on Power Aware Computing (HotPower), 2009.
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Case study: Desktops
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Predict when it is convenient to turn machines off
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Machine usage models needed
Correlation between power consumption and CPU usage
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Case study: Monitors
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Consumption comparable to desktops (40 – 130 W)
Usage pattern: almost always on, even if not in use
Consumption reduction by configuration parameters
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Less brightness, less power consumption
Change desktop backgrounds (10% savings)
Total savings: 10 – 28%
Change of several parameters
Change desktop backgrounds
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Case study: Network Switches
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Network equipment is not energy proportional
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Same energy consumption independently of the usage
Maximum usage # Maximum efficiency
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HP switch consumes more due to:
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Fan load
Backplane structure
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Case study: Server rack
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10 identical 1U servers in a server rack of 40 servers
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Each server consumed 245 W
But server at top of the rack consumed 20% more power
Methodology used for reasoning about odd result
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Swap top and bottom servers
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Top part is warmer than bottom
Same workload in all of them
Replaced server on top increased from 250 W to 270 W
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Previous top server consumption back to normal 245 W
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Case study: Server rack
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We should analyse more aspects than CPU usage alone
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Load
Temperature
Configuration
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http://openclipart.org/detail/139525/server-rack-by-moini
Conclusions
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By analysing power consumption we can:
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Power consumption and usage pattern
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Reduce energy consumption
Rethink system designs
Important for further energy savings
Insights revealed by PowerNet:
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Monitor configuration can reduce consumption (25%)
Identical server machines can have different power
consumption depending on rack placement
Network equipment is not energy proportional
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Classification
Production
phase
Design
phase
Use
phase
Recycling
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End-of-life
phase
Residues
Resources
ICT Services
Energy Dumpster Diving
Discussion
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Discussion
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Which is the cost of maintenance of this system? Cost of
the system itself? (not enough discussed in the paper)
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Discussion
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Which is the cost of maintenance of this system? Cost of
the system itself? (not enough discussed in the paper)
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Do you think this is a permanent infrastructure? Or is just
to do the study? (discussion of key ideas of the paper)
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Discussion
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Which is the cost of maintenance of this system? Cost of
the system itself? (not enough discussed in the paper)
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Do you think this is a permanent infrastructure? Or is just
to do the study? (discussion of key ideas of the paper)
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Should these meters be installed in all the systems by
default? (possible ideas to improve the work)
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Discussion
!
Which is the cost of maintenance of this system? Cost of
the system itself? (not enough discussed in the paper)
!
Do you think this is a permanent infrastructure? Or is just
to do the study? (discussion of key ideas of the paper)
!
Should these meters be installed in all the systems by
default? (possible ideas to improve the work)
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Do you think we should create a standard to declare power
values and utilisation values? (go further from the paper)
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Discussion
!
Which is the cost of maintenance of this system? Cost of
the system itself? (not enough discussed in the paper)
!
Do you think this is a permanent infrastructure? Or is just
to do the study? (discussion of key ideas of the paper)
!
Should these meters be installed in all the systems by
default? (possible ideas to improve the work)
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Do you think we should create a standard to declare power
values and utilisation values? (go further from the paper)
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Suitable for home? (go further from the paper)
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Web Interface
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Powertron
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http://powernet.stanford.edu/
Another similar project
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The TrendMETER
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http://trend.polito.it