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Nilton Bila, Eyal de LaraUniversity of TorontoMatti Hiltunen, Kaustubh Joshi, H. Andres Lagar-CavillaAT&T Labs ResearchMohadev SatyanarayananCargie-Mellon University
Offices & homes crowded with desktop PCs PCs idle on average 12 hours a day (Nedevschi09) 60% of desktops remain powered overnight (Webber06) Why do we care?Dell Optiplex 745 DesktopPeak power: 280WIdle power: 102.1WSleep power: 1.2W2
Always-on semanticsBackground Applications: IM, E-mail, VoIPRemote Access: files, remote admin3
Encapsulate user session in VMWhen idle, migrate VM to consolidation serverand power down PC.When busy, migrate back to user’s PC4
Encapsulate user session in VMWhen idle, migrate VM to consolidation serverand power down PC.When busy, migrate back to user’s PCDownside: VMs are large5
Insight: Idle VM access only a small fraction oftheir memory and disk stateMigrate just the working set6
Small migration footprint Client Network Fast migrationLow energy costGentle on network resourcesServer High consolidation ratios7
Small migration footprint Client over 3G or WiFimobile devicesNetwork Fast migrationLow energy costGentle on network resourcesServer High consolidation ratios8
Small migration footprint Client over 3G or WiFimobile devicesNetwork Fast migrationLow energy costGentle on network resourceswide area (IaaS)Server High consolidation ratios9
Length of sleep times? Size of the memory footprint? Prototyped simple on-demand migrationapproach with SnowFlock Monitor memory and disk page migration to cloneVM10
Dell Optiplex 745 Desktop 4GB RAM, 2.66GHz Intel C2DPeak power: 280WIdle power: 102.1WSleep power: 1.2WVM Image: Debian Linux 51GB RAM12 GB disk11
WorkloadDescriptionLoginThe login screen of a Linux desktop system (GDM).E-mailMozilla thunderbird connected to an IMAP e-mail server. The client pollsthe server every 10 minutes.IMThe Pidgin multi-protocol IM client connected to an IRC room with morethan 100 users.MultitaskA Gnome Desktop session with the E-mail client, IM client, Spreadsheet(OpenOffice Calc), PDF Reader (Evince) and file browser (Nautilus)12
Migration Pattern: E-mailSpatial locality Potential benefits for pre-fetching13
Migration Pattern: E-mail 98% of request arrive in close succession14
E-mail EmailMultitaskMultitaskTotal sleep of 17 to 46 minutes out of 1hourEnergy savings of 50% to 0.Sleep opportunities increase over time15
Inefficient in 1st hour69% energy savings overall16
A cloud node with 4GB of RAM can run 30VMs17
Frequent power cycling reduces hw life expectancy andlimits power savings Reduce number of sleep cycles and increase sleep durationPredict page access patterns and prefetchLeverage content addressable memoryFast reintegrationPolicies When to migrate/re-integrate?When does the desktop go to sleep?On re-integration, should state be maintained in the cloud? Forhow long?18
Remote wake up: Wake-on-LAN, Wake-on-Wireless No support for always-on applications Short sleep timesProtocol proxy: Nedevschi’09, Reich’10 Limited flexibilityApplication proxy: Somniloquy, Turducken, SleepServer Applications must be modified Management of applications may be complexFull VM Migration: LiteGreen Low consolidation ratios Bandwidth intensive19
Proposed partial VM migrationEven naïve partial VM migration can reduce energyuse of idle desktop 32 – 50% over an hour-long idle interval69% overnightIdle desktop sessions have a memory footprint anorder of magnitude smaller than their RAM allocation.Partial VM migration can save medium to large sizeorganizations tens to hundreds of thousands of dollars20
ronto.eduQuestions?21
Dollars (thousands)600500No Sleep400Partial Migration30020010001001,00010,000# Desktops 44% to 60% reduction in energy costs22
2 Offices & homes crowded with desktop PCs PCs idle on average 12 hours a day (Nedevschi09) 60% of desktops remain powered overnight (Webber06) Why do we care? Dell Optiplex 745 Desktop Peak power: 280W Idle power: 102.1W Sleep power: 1.2W
