Pat Stemen Senior Program Manager Microsoft Corporation The Power of WinHEC 2008 CORT540 Windows 7 Power Management Overview Now MBLT541 Improving Platform Energy Efficiency part 1 ID: 249216
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Slide1Slide2
Windows 7 Power Management Overview
Pat Stemen
Senior Program Manager
Microsoft CorporationSlide3
The Power
of WinHEC 2008!
COR-T540
Windows 7 Power Management Overview
Now
MBL-T541
Improving
Platform Energy Efficiency (part 1)
Today, 2:00–3:00
Room 404
MBL-T541
Improving Platform
Energy Efficiency (part 2)
Today, 3:15–4:15
Room 404
COR-C622
Discussion: Windows 7 Power Management
Today, 4:30–5:30
Room 402A
COR-T542
NDIS 6.20: Core Network
Power Management Fundamentals
Today, 4:30–5:30
Room 404
ENT-T551
Windows
Server Power Management Overview
Thursday, 2:00–3:00
Hall K
ENT-T552
Windows Server Power
Management
Implementation Details
Thursday, 3:15–4:15
Hall K
COR-C633
Microsoft Tools
for Energy
Efficiency Diagnostics
Thursday, 2:00–3:00
Room 402ASlide4
Agenda
Windows Energy Efficiency Vision
Idle Power and Background Activity
Device Power Management
Timers and Alarms
Power Policy Enhancements
Idle Detection
Power Efficiency DiagnosticsSlide5
Windows Energy
Efficiency Vision
The Windows OS enables the most energy-efficient computing platform, regardless of underlying
hardware, attached devices or software workload.
Idle
Efficiency
Workload Scaling
Always Available
Self
Diagnosing
Standards Based
Management
Extensible but ResilientSlide6
Deep Focus on Idle
6Slide7
Background Activity Improvements
Idle dominates almost all use
scenarios for client systems
Reducing idle power key to
extending battery life
Periodic background activity increases system power consumption
Very frequent events impact
processor and chipset power
Long-running infrequent events prevent the system from idling to sleepSlide8
Frequent Idle Activity
Specific Windows 7 improvements
Eliminate TCP DPC timer on every
system timer interrupt
Reduce frequency of USB driver
maintenance timers
Intelligent Timer Tick Distribution (ITTD)
Timer Coalescing
Eliminate idle activity in drivers and applicationsTarget average idle period greater than 100msSlide9
Timer Coalescing
Platform energy efficiency can be
improved by extending idle periods
New timer coalescing API enables callers
to specify a tolerance for due time
Enables the kernel to expire multiple timers at the same time
Extensions should integrate with Windows 7 API/DDI
Timer tick
15.6 ms
Periodic Timer Events
Windows 7
VistaSlide10
Background Process Management
Background activity on the macro scale (minutes, hours) also important for power
E.g., disk defragmentation, AV scans
Prevents low-power idle and sleep modes
Unified Background Process Manager (UBPM)
New Windows 7 infrastructure
Drives scheduling of services and scheduled tasks
Transparent to users, IT pros, and existing APIs
Enables trigger-starting servicesDelivers usage data and metrics to Microsoft via CEIPSlide11
Trigger-Start Services
Many services configured to Autostart
and wait for rare events
UBPM enables Trigger-Start services
based on environmental changes
Device arrival/removal, IP address change, domain join, etc.
Examples
Bluetooth service is started only if a Bluetooth radio is currently attached
BitLocker encryption service started only when new volumes detectedCall to ActionLeverage trigger-start capability for value-add servicesValidate performance impact with XPerf toolsSlide12
Some
Trigger-Start
Services In Windows 7
Service Name
Description
Trigger Type
AELookupSvc
Processes application compatibility cache requests for applications as they are launched
Custom ETW
BDESVC
Provides BitLocker client services for user interface and auto-unlocking of data volumesCustom ETW
BTHSERVThe Bluetooth service supports discovery and association of remote Bluetooth devices.Device
SensorsMTPMonitor
Monitors MTP (Media Transfer Protocol) sensors (such as a cell phone with a GPS receiver) to communicate sensor data to programs
Device
TabletInputService
Enables Tablet PC pen and ink functionality
Device
WinDefend
Protection against spyware and potentially unwanted software
Group PolicySlide13
Device Power Management
Adaptive display brightness
Dim the mobile PC display after
a period of user inactivity
Intelligent policy—timeout automatically adjusts with user input
Does not interfere with presentations,
full-screen media playback
Processor power management
Updates to core performance state algorithmCore parkingSlide14
Device Power Management
Audio
Support for the latest Intel HD Audio
low-power specifications
USB audio class selective suspend
Bluetooth
Radio enters selective suspend
when connections are in sniff mode
Wired LAN runtime idle detectionNIC automatically enters D3 when media is disconnectedSlide15
Power Policy Enhancements
Iterative evolution of Vista power policy
Continue 3 plans:
Performance, Balanced, Power Saver
Same toolset
Refined UI elements
New power settings for Windows 7 features
Minor changes to idle timeout defaults
OEMs must continue to tailor policy for specific platformsE.g., meet regulatory compliance standardsSlide16
New Windows 7 Power Policies
Name
GUID
Description
Default (Balanced)
AC
DC
Unattended sleep timeout
7bc4a2f9-d8fc-4469-b07b-33eb785aaca0
Determines the amount of inactivity time before the system automatically sleeps if the computer resumed without a user present
2 minutes
2 minutes
System cooling policy
94d3a615-a899-4ac5-ae2b-e4d8f634367f
Determines if Active or Passive cooling should be favored for thermal zones
Active
Active
Reserve battery level
f3c5027d-cd16-4930-aa6b-90db844a8f00
Configures the percentage of battery capacity remaining before displaying the reserve battery warning
n/a
7%
AHCI link power mode
0b2d69d7-a2a1-449c-9680-f91c70521c60
Configures AHCI link power
modes
(
HIPM, DIPM) and link power
states
(
Partial, Slumber, Active)
HIPM, Partial
HIPM, Slumber
Allow System Required Policy
a4b195f5-8225-47d8-8012-9d41369786e2
Enable applications to prevent the system from idling to sleep
Enabled
Enabled
Dim Display After
17aaa29b-8b43-4b94-aafe-35f64daaf1ee
Determines the amount of inactivity time before the system automatically reduces the brightness of the display on a mobile PC
5 minutes
2 minutesSlide17
Power WMI Provider
Enables power policy configuration
through standard WMI interface
Change power setting values
Activate a given plan
Conforms to DMTF data model
To get started…
Change a power setting:
Win32_PowerSettingActivate a plan: Win32_Plan.Activate() methodAttend ENT-T552 Windows Server Power Management Implementation Details for additional detailsSlide18
Wake Timers
Opportunity to improve mobile PC experience
by reducing spurious wake events
E.g., system wakes up in bag due to application request, remains on, drains battery
Windows 7 mobile PCs will not program
wake timer alarm by default
Excludes doze to hibernate
Wake timers continue to be enabled
by default on desktop systemsPower policy control to configure wake timersSlide19
Low Battery Experience
7%
16%
5%
Automatic Hibernate
All thresholds are configurable in power policySlide20
Media Playback Improvements
Refined optical drive spin-down mechanism
Configurable power policies to force interlaced content to render at 30 fps
CPU utilization improvements for
copy-protection and DRM compliance
Architectural changes in DWM to
optimize CPU and memory utilization
Attend
MBL-T541 Improving Platform Energy Efficiency for detailed power savings informationSlide21
Idle Detection
Windows 7 is aggressive about placing
the system in sleep when idle
User input and application availability
requests only
Availability requests allow applications
to request temporary overrides on
power management
Media center recording service prevents idle to sleep when recording TVWindows Media Player prevents display from turning off while watching DVDSlide22
Idle Detection
Windows 7 improves failed
idle detection diagnostics
Use PowerCfg utility to inspect for requests
PowerCfg /REQUESTS
Network file sharing
Open files in a client-side cache (offline files)
will not prevent the client from sleeping
Policy override capabilityOption to override individual availability requestsOption to override all availability requestsIdle detection will be based solely on user inputSlide23
Idle Detection Diagnostics
demoSlide24
Power Efficiency Diagnostics
PowerCfg command-line utility expanded to detect common energy efficiency problems
USB device selective suspend
Processor Power Management (PPM)
Inefficient power policy settings
Platform timer resolution
Platform firmware problems
Battery capacity
…and othersHelps detect major problems at time of system integrationSlide25
Power Efficiency Diagnostics
Designed to evaluate problems when the system is idle
Close open applications and documents
“
PowerCfg /ENERGY
” at the command line
to start tracing
Inbox with Windows 7 only
Leverages new inbox ETW instrumentationAdvanced users can run utility and view HTML outputAutomatically executed when the system is idleReports data to Microsoft via Customer Experience Improvement Program (CEIP)Attend COR-C633 Microsoft Tools for Energy
Efficiency Diagnostics for demo and detailsSlide26
Power Efficiency Diagnostics
Detected problems
Problem Area
Data Collected
Warning Threshold
Error
Threshold
USB Device
Selective Suspend
Individual device suspend transitions
%
of time device was in suspend state
< 80% suspend time
< 50
%
suspend
time
Power Policy Settings
Idle timeouts (dim, display, sleep)
PPM configuration
Power plan personality
802.11 Wireless Power Save
Idle timeouts <
EnergyStar
4.0 Recommendations
Idle timeouts disabled
Processor Utilization
Overall utilization
Per-process
utilization
(
any process over .1%)
Top 3 module utilization in each process
Total utilization >2%
Total
utilization
>
4%Slide27
Power Efficiency Diagnostics
Detected problems
Problem Area
Data Collected
Warning Threshold
Error
Threshold
Timer Resolution Requests
Current system timer interrupt period (e.g., 15.6ms)
Applications with outstanding timer requests, request amount
None
Timer interrupt
period < 15.6ms
Power Requests
Applications with outstanding power requests (Display, Sleep, Away Mode)
None
Each outstanding power request
Platform Capabilities
Sleep state availability
Display dimming capability
Firmware validation problems
PCI Express ASPM status
None
If any capability is disabled or missing
Battery Capacity
Battery static data (make, model
,
serial
number, manufacture date)
Last full
charge capacity/design
capacity
(Last Full
Charge Capacity/Designed
Capacity
) < 50
%
(Last Full
Charge Capacity/Designed
Capacity
) < 40
%Slide28
Call to Action
Attend power and energy efficiency sessions at WinHEC
Focus on idle—reduce idle activity
and power consumption
Convert value-add and custom
services to trigger-start model
Review new power policy options,
tailor for specific platforms
Validate new platform power management using Power Efficiency DiagnosticsSlide29
Additional Resources
Web Resources
Windows Hardware Developer Central – ACPI / Power Management
http://www.microsoft.com/whdc/system/pnppwr/powermgmt/default.mspx
Battery Life and Energy Efficiency
http://www.microsoft.com/whdc/system/pnppwr/mobilepwr.mspx
Designing Efficient Background Processes for Windows (Trigger-Start Services) http://go.microsoft.com/fwlink/?LinkId=128622Power Policy Configuration and Deployment in Windows Vista http://www.microsoft.com/whdc/system/pnppwr/powermgmt/PMpolicy_Vista.mspx
Related SessionsMBL-T541 – Improving Platform Energy EfficiencyCOR-C633 – Microsoft Tools for Energy Efficiency DiagnosticsCOR-C622 – Discussion: Windows 7 Power Management
ENT-T551 – Windows Server Power Management OverviewENT–T552 – Windows Server Power Management Implementation Details Emailenergy@microsoft.comSlide30
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2008
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. Because
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