Transcript PC02  Pat Stemen Senior Program Manager Microsoft Corporation Processor Power Over Time12080400 1985 1987 1989 1991 1993 1995 1997 1999 2001 2003 2005

PC02
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Pat Stemen
Senior Program
Manager
Microsoft Corporation
Processor Power Over Time
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1985 1987 1989 1991 1993 1995 1997 1999 2001 2003 2005
Clean compared to OEM Pre-install
Windows Vista RTM Idle
A
B
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J
K
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M
N
O
P
Q
-20%
-10%
0%
Clean Install Battery Life Is Better
10%
20%
30%
40%
50%
60%
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Why does idle power matter?
• Most user workloads are dominated by
idle time
• Reducing idle power reduces the “base” power
consumption of the system
• OEMs are focusing on driving down system
idle power for regulatory compliance
Watts
Components:
Workloads
Workloads
~8-12W Idle
Idle
0W - Off
Time
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Platform hardware, devices and drivers
Core OS and kernel
OS services (indexing, background tasks, etc.)
Applications and services
Watts
• Trade
Resource
or
“Racequality
to utilization
Sleep”
optimizations
performance
for
• Execute rapidly
power
• Reduce
at savings
high power
powerby
eliminating unnecessary
• Examples
• Quickly
activity re-enter
• low-power
Index only highstate
• Examples:
items
•• priority
Extend
average
Events and
notifications
• Disable
animations
idle
duration
instead of polling
•• DVD
playback
at
• Examples
Extending
polling
of 60fps
intervals
• 30fps
Timer instead
coalescing
•
Idle Power
Idle
0W - Off
Time
Eliminating periodic
disk activity
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Internal Microsoft measurements, Intel processor
100%
70%
50%
40%
30%
20%
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10%
0
Idle
5
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Timer tick
15.6 ms
Vista
Periodic Timer
Events
Windows 7
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BOOL
DllImport("kernel32.dll")]
WINAPI
static extern bool SetWaitableTimerEx(
SetWaitableTimerEx(
IntPtr hTimer,
__in
HANDLE hTimer,
ref long lpDueTime,
__in
const LARGE_INTEGER *lpDueTime,
int lPeriod,
__in
LONG lPeriod,
TimerCompletionDelegate
__in_opt PTIMERAPCROUTINE pfnCompletionRoutine,
pfnCompletionRoutine,
__in_opt LPVOID lpArgToCompletionRoutine,
IntPtr lpArgToCompletionRoutine,
__in_opt PREASON_CONTEXT WakeContext,
IntPtr WakeContext,
__in
ULONG TolerableDelay
ulong TolerableDelay
);
);
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1
0
15.6ms
(default)
1 ms
CPU Power
System Power
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Example HDD Power
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//
// Create a SystemRequired request to keep the system from automatically sleeping while downloading a file.
//
POWER_REQUEST_CONTEXT DownloadPowerRequestContext;
HANDLE DownloadPowerRequest;
//
// Set up the diagnostic string
//
DownloadPowerRequestContext.Version = POWER_REQUEST_CONTEXT_VERSION;
DownloadPowerRequestContext.Flags = POWER_REQUEST_CONTEXT_SIMPLE_STRING;
DownloadPowerReqeustContext.Reason.SimpleReasonString = L”My application is downloading files.”
//
// Create the request, get a handle
//
DownloadPowerRequest = PowerCreateRequest(&DownloadPowerRequestContext);
//
// Set the request
//
PowerSetRequest(
DownloadPowerRequest,
PowerRequestSystemRequired
);
// Download the File...
//
// Clear the request
//
PowerClearRequest(DownloadPowerRequest);
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http://www.microsoft.com/whdc/system/sysperf/perft
ools.mspx
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http://www.microsoft.com/whdc/system/pnppwr/powermgmt/PM_apps.mspx
http://msdn.microsoft.com/en-us/magazine/cc163386.aspx
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http://www.microsoft.com/whdc/system/pnppwr/powermgmt/PMapps_samp.mspx
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http://msdn.microsoft.com/en-us/magazine/cc163386.aspx
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http://www.codemagazine.com/articleprint.aspx?quickid=0512102&printmode=true
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http://www.microsoft.com/whdc/system/sysperf/perftools.mspx
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http://www.microsoft.com/whdc/DevTools/WDK/WDKpkg.mspx
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C# function definitions and enumerations
[DllImport("kernel32.dll")]
static extern IntPtr PowerCreateRequest(
ref POWER_REQUEST_CONTEXT Context
);
[DllImport("kernel32.dll")]
static extern bool PowerSetRequest(
IntPtr PowerRequestHandle,
PowerRequestType RequestType
);
[DllImport("kernel32.dll")]
static extern bool PowerClearRequest(
IntPtr PowerRequestHandle,
PowerRequestType RequestType
);
enum PowerRequestType {
PowerRequestDisplayRequired = 0,
PowerRequestSystemRequired,
PowerRequestAwayModeRequired,
PowerRequestMaximum
}
const int POWER_REQUEST_CONTEXT_VERSION = 0;
const int POWER_REQUEST_CONTEXT_SIMPLE_STRING = 0x1;
const int POWER_REQUEST_CONTEXT_DETAILED_STRING = 0x2;
C# structures
//
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//
//
//
//
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//
//
//
Note:
Windows defines the POWER_REQUEST_CONTEXT structure with an
internal union of SimpleReasonString and Detailed information.
To avoid runtime interop issues, this version of POWER_REQUEST_CONTEXT
only supports SimpleReasonString. To use the detailed information,
define the PowerCreateRequest function with the first parameter of type
POWER_REQUEST_CONTEXT_DETAILED.
[StructLayout(LayoutKind.Sequential, CharSet=CharSet.Unicode)]
public struct POWER_REQUEST_CONTEXT
{
public UInt32 Version;
public UInt32 Flags;
[MarshalAs(UnmanagedType.LPWStr)] public string SimpleReasonString;
}
[StructLayout(LayoutKind.Sequential)]
public struct PowerRequestContextDetailedInformation
{
public IntPtr LocalizedReasonModule;
public UInt32 LocalizedReasonId;
public UInt32 ReasonStringCount;
[MarshalAs(UnmanagedType.LPWStr)] public string[] ReasonStrings;
}
[StructLayout(LayoutKind.Sequential, CharSet = CharSet.Unicode)]
public struct POWER_REQUEST_CONTEXT_DETAILED
{
public UInt32 Version;
public UInt32 Flags;
public PowerRequestContextDetailedInformation DetailedInformation;
}
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