Energy Dumpster Diving- Example presentation-
Department of Computer and Information Science (IDA)Linköping University, Sweden
Paper written by:M. A. Kazandjieva, B. Heller, P. Levis, C. Kozyrakis
Stanford UniversityIn Proceedings of HotPower workshop 2009
Presented by:Simin Nadjm-Tehrani / Klervie Toczé / Rodrigo Moraes
January 27, 2020
Overview
Large computing systems Individual elements contribute to consumption Sources of waste difficult to identify
PowerNet sensing infrastructure Power consumption of individual devices Correlation with usage information
Analysis of consumption Reveal device inefficiencies Usage scenarios that waste energy
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PowerNet
Large-scale distributed sensing infrastructure
Provides Per-device energy measures Usage statistics
Deployed in real office building environment
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PowerNet deployment
Stanford Computer Science building Office environment
Desktops Monitors
Data center server rack Small networking closet
Network switches
Some numbers 85 power meters Utilisation data collected
15 desktops 10 servers 5 switches
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PowerNet components
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Wired power meters
Watt's Up .NET with Ethernet interface
Disadvantages: 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
Implemented as a customised mote Low power processor (1mA active, 1uA sleep) Digital power meter chip
Characteristics 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
Motes can talk to each other without cables Data is forwarded to the sink
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 Applicationshttp://www.ida.liu.se/~rtslab/courses/wsn/Basics.pdf
MotesSink
Computeror server
Gateway
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Utilisation metering
PowerNet monitors device usage
Desktops and servers CPU utilisation Python script tracks utilisation
Network switches Traffic statistics for each port Monitor hardware counters via SNMP
Server rack Balanced workload
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Data management and visualisation
Data stored in a central server Kept in a MySQL database
Power and utilisation data correlated Data synchronised in time using timestamps Analysis of consumption related to activity
Data visualisation through website 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
Put desktops in sleep mode when not used User and CPU must be inactive
Case study: Desktops
Predict when it is convenient to turn machines off Machine usage models needed Correlation between power consumption and CPU usage
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Case study: Monitors
Consumption comparable to desktops (40 – 130 W) Usage pattern: almost always on, even if not in use Consumption reduction by configuration parameters
Less brightness, less power consumption Change desktop backgrounds (10% savings)
Total savings: 10 – 28%
Change desktop backgroundsChange of several parameters
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Case study: Network Switches
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Network equipment is not energy proportional Same energy consumption independently of the usage Maximum usage Maximum efficiency
HP switch consumes more due to: Fan load Backplane structure
Case study: Server rack
10 identical 1U servers in a server rack of 40 servers Each server consumed 245 W But server at top of the rack consumed 20% more power
Methodology used for reasoning about odd result Swap top and bottom servers
Top part is warmer than bottom Same workload in all of them
Replaced server on top increased from 250 W to 270 W Previous top server consumption back to normal 245 W
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Case study: Server rack
We should analyse more aspects than CPU usage alone Load Temperature Configuration
15 http://openclipart.org/detail/139525/server-rack-by-moini
Conclusions
By analysing power consumption we can: Reduce energy consumption Rethink system designs
Power consumption and usage pattern Needs to be measured/recorded before further savings
Insights revealed by PowerNet: 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
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Design phase
Productionphase
Usephase
End-of-lifephase
Res
ourc
es
Res
idue
s
ICT Services
Recycling
Energy Dumpster Diving
Discussion
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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)
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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)
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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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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)
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)
Do you think we should create a standard to declare power values and utilisation values? (go further from the paper)
Suitable for home? (go further from the paper)
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Web Interface
Powertron
http://powernet.stanford.edu/24
Additional material
Another similar project
The TrendMETER
http://trend.polito.it25
Additional material
Discussion
The problem of the batteries of the sensors. Which is the cost of maintenance of this system?(go further from the paper)
Do you think this is a permanent infrastructure? Or is just to do the study? (discuss the basic idea/approach of the paper)
Should these meters be installed in all the systems by default? (how to improve)
Do you think we should create a standard to distribute power values and utilisation values?
Suitable for home? (where can apply this methodology...) Cost of the system itself?
http://www.ida.liu.se/~TDDD50
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TinyOS
TinyOS is an operating system for resource-constrained devices
It offers you the tools to use the available features ofyour hardware
Written in nesC, a C dialect
May be a whole slide for TinyOS is too muchbecause distracts the attention from the main topic
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