Transcript Windows 7: Designing Efficient Background Processes

PC19

Vikram Singh
Program Manager
Microsoft Corporation
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Performance
• Responsiveness to the user
• Consumes resources from
foreground applications
• Boot, Shutdown, Logoff, etc.
Security
• Activity may require system
privileges
• Successful attack may
compromise entire system
Reliability
• Memory leaks
• System crashes, hangs
• Dependent application
crashes
Power Consumption
• Extra disk, CPU utilization
• Decrease in battery life
• Prevents idle efficiencies
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required
Resource
Quantity
File I/O
47,286
Copy-on-Write (COW) Pages
4,656 (~18MB)
Memory Pages (Total)
15,967 (~60MB)
Registry Operations
38,508
Threads
367
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50
40
30
20
10
0
Boot Time
Shutdown Time
seconds
seconds
24.7
46.1
Clean
IT
45
30
15
0
0%
Clean
IT
15 second trace
15 second trace
4%
30
Disk Read Count
Idle CPU Utilization
8%
25.6
40,000
1.01%
6.04%
Clean
IT
20,000
0
10,192
Clean
31,401
IT
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Scheduled Task
Windows Service
• Continuous activity
from boot to
shutdown
• Service Control
Manager (SCM)
programming model
• Can specify
dependency
• Short
duration action
• Idle activity
• Take action
on user login
• Standalone
executable or
out-of-process
COM server
• Generally execute
in user session
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Auto_Start
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Auto_Start
Trigger-Start
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Trigger
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TabletInputService
Trigger-Start
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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 volumes
Custom ETW
BTHSERV
The 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 Policy
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Trigger-Start
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Demand_Start
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[DllImport(“advapi32.dll”, SetLastError=true)]
Public static extern bool ChangeServiceConfig2(
IntPtr hService,
uint32 dwInfoLevel,
IntPtr lpInfo
);
Const uint32 SERVICE_CONFIG_REQUIRED_PRIVILEGES_INFO = 6
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// Example UPS Service
protected override void OnStart (string[] args)
{
IntPtr ServiceHandle;
IntPtr RequiredPrivilegesString;
// set required privileges
string RequiredPrivileges =
“SeShutdownPrivilege\0\0”;
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RequiredPrivilegesString =
Marshal.StringToHGlobalAuto(RequiredPrivileges);
ChangeServiceConfig2(
this.ServiceHandle,
SERVICE_CONFIG_REQUIRED_PRIVILEGES_INFO,
RequiredPrivilegesString
);
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}
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Kernel
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Detects Idle Condition
Task Scheduler
(schedule)
Launches Task
Power Efficiency
Diagnostics
(powercfg.exe)
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Trigger-Start
Auto_Start
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http://go.microsoft.com/fwlink/?LinkId=128622
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http://download.microsoft.com/download/9/c/5/9c5b21678017-4bae-9fde-d599bac8184a/Vista_Services.doc
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http://msdn.microsoft.com/enus/library/ms685150(VS.85).aspx
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http://msdn.microsoft.com/en-us/library/aa383614.aspx
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http://www.microsoft.com/whdc/system/sysperf/perftools.
mspx
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www.microsoftpdc.com
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