A Brief Tutorial on Power Management in Computer Systems

David Chalupsky, Intel

Description

A Brief Tutorial on Power Management in Computer SystemsDavid Chalupsky, Emily Qi, & Ilango Ganga Intel Corporation March 13, 2007Objective & AgendaObjective:• Establish a common foundation for EEESG work by providing an overview and history of PC power management and LAN use in that context.Agenda:• High Level overview of PC power management– Links to additional information• How Ethernet is utilized in Contemporary PC Power Management• Making Power Management and Ethernet more effective in the future2 March 11, 2007 File: chalupsky_01_0307PC Power States circa 1990• ON• OFFSounds nice & simple. What’s wrong with that?• Time to boot the PC from a cold start took too long, and got longer as PCs became more complex.• As a result, people left their PCs on all the time, wasting energy.3 March 11, 2007 File: chalupsky_01_0307Historical (1990’s) Motivation for Power Managementby market segmentLaptops & Battery Powered Devices– Battery Life is a key product feature, thus– Commercial incentive has always been there– Vendor-specific solutions preceded standardsDesktop PCs– Little end user benefit perceived for PM. – Initial attention to PM in 1992 with the release of EPA’s Energy Star program and international counterparts.Server Systems– Historically, a very performance oriented segment– Always on & ready for maximum performance– Recent, market-driven, attention to power due to high cost of electricity & cooling in Data Centers– EPA ...

Informations

• Publié par: Orzu
• Nombre de lectures: 31
• Langue: English

Extrait

A Brief Tutorial on Power Management in Computer Systems

David Chalupsky, Emily Qi, & Ilango Ganga Intel Corporation March 13, 2007

Objective & Agenda

Objective: • Establish a common foundation for EEESG work by providing an overview and history of PC power management and LAN use in that context.

Agenda: • High Level overview of PC power management – Links to additional information • How Ethernet is utilized in Contemporary PC Power Management • Making Power Management and Ethernet more effective in the future

2 March 11, 2007 File: chalupsky 01 0307 _ _

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3 March 11, 2007 File: chalupsky_ _ 01 0307

• • OFF

• got longer as PCs became more complex. • energy.

Sounds nice & simple. What’s wrong with that?

PC Power States circa 1990

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Historical (1990’s) Motivation for Power Management by market segment

Laptops & Battery Powered Devices – Battery Life is a key product feature, thus – Commercial incentive has always been there – Vendor-specific solutionsprecededstandards Desktop PCs – Little end user benefit perceived for PM. – Initial attention to PM in 1992 with the release of EPA’s Energy Starprogram and international counterparts. Server Systems – Historically, a very performance oriented segment – Always on & ready for maximum performance – Recent, market-driven, attention to power due to high cost of electricity & cooling in Data Centers – EPA just beginning to focus on Servers in 2006/2007

4 March 11, 2007 File: chalupsky_01_0307

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Enter the Sleep State –

To reduce PC energy consumption during periods of inactivity, the industry introduced the concept sleep, or standby, states.

5 March 11, 2007 File: chalupsky_01_0307

Waking the System • Return to active stat • Keyboard, Mouse, Power Button

Goals • Powe •

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March 11, 2007 File: chalupsky_01_0307

In corporate environments, PCs were STILL being left on all night. • performed at night, over the LAN. •IT needed system availability. • and be turned on remotely for management. •

Enter Wake On LAN

6

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Power Management Standards

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For multi-vendor interoperability, standards were required • – Advanced Power Management – Early-mid 1990’s •

uCrrnet: ACPI 

– Advanced Configuration and Power Interface – 1996 – present – ACPI is still evolving to comp rehend new system capabilities – Coordinated with supportinginterfacespecifications: •PCI Power Management, USB, Cardbus, PCI Express, etc. – Coordinated with supportingDevice Classspecifications: •Network, Storage, Graphics, etc.

7 March 11, 2007 File: chalupsky_01_0307

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March 11, 2007 File: chalupsky_01_0307

8

Advanced Power Management (APM) The Legacy Method

– No uniform user experience

BIOS code/IP

 sup LAN

• • • • • • •

–Operating System has no knowledge of what APM does

devices into low power states

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• • •

ty

Allows OS-directed Power Management (OSPM) • •

An “interface” specification

– Configuration tables – Interpreted executable function interface (Control Methods) – Motherboard device enumeration and configuration

Defines • •

9

March 11, 2007 File: chalupsky_01_0307

Advanced Configuration and Power Interface

ACPI

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defined for multiple levels of the system – Global view: Gx states – System: Sx states – Processor: Cx states – PCI / PCI-X Bus: Bx states – PCI Express Links: Lx states – Devices: Dx states • General Trend of the state numbers –0is the Active state - G0, S0, D0 – System is available to User –1-nare sleep states –highernumber corresponds tolowerpower. – User perception is OFF for all of these sleep states.

•

System Hierarchy of Power Management under ACPI

10 March 11, 2007 File: chalupsky_01_0307

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11

In the Interest of Time…

File: chalupsky_01_0307

March 11, 2007

in the Backup section for the interested student.

•