X86/X64的页面错误异常号是0xe,页面错误：一个线程企图访问虚拟内存中没有定义的或者已经存在的页面时产生的异常。Windows支持的硬件体系结构允许最多可达256个IDT项。一台PC所能支持的中断IRQ数量是由该机器的中断控制器的具体设计决定的。
由于大多数X86都依赖一个硬件i8259A可编程中断控制器（PIC）在单处理器系统上有15条中断线。
0:kd>!idt
DumpingIDT:
37:806e6864hal!PicSpuriousService37
3d:806e7e2chal!HalpApcInterrupt
41:806e7c88hal!HalpDispatchInterrupt
50:806e693chal!HalpApicRebootService
62:8a3019548a38ecb8(KINTERRUPT8a301918)
63:89d3d044NDIS!ndisMIsr(KINTERRUPT89d3d008)
8a225cb8(KINTERRUPT89cc7bb0)
73:8a056becVIDEOPRT!pVideoPortInterrupt(KINTERRUPT8a056bb0)
8a225cb8(KINTERRUPT89cd8938)
8a225cb8(KINTERRUPT89ccf938)
83:8a2b6afc8a38ecb8(KINTERRUPT8a2b6ac0)
8a38ecb8(KINTERRUPT8a2b5bb0)
NDIS!ndisMIsr(KINTERRUPT89ce2930)
92:899e1becserial!SerialCIsrSw(KINTERRUPT899e1bb0)
93:899e8044i8042prt!I8042KeyboardInterruptService(KINTERRUPT899e8008)
a4:89cdfbec8a225cb8(KINTERRUPT89cdfbb0)
8a225cb8(KINTERRUPT89cd0bb0)
b1:8a36f044ACPI!ACPIInterruptServiceRoutine(KINTERRUPT8a36f008)
8a1d0cb8(KINTERRUPT8a075508)
b4:89d38bec8a225cb8(KINTERRUPT89d38bb0)
HDAudBus!AzController::Isr(KINTERRUPT89d32410)
c1:806e6ac0hal!HalpBroadcastCallService
d1:806e5e54hal!HalpClockInterrupt
e1:806e7048hal!HalpIpiHandler
e3:806e6dachal!HalpLocalApicErrorService
fd:806e75a8hal!HalpProfileInterrupt
fe:806e7748hal!HalpPerfInterrupt
查看PIC和APIC
0:kd>!pic
-----IRQNumber-----000102030405060708090A0B0C0D0E0F
Physicallyinservice:YY.Y....YY.Y....
Physicallymasked:YYY.Y.Y.YYY.Y.Y.
Physicallyrequested:.Y.Y.....Y.Y....
0:kd>
对于本机单CPU双核来看：是否使用了MPSHAL？
lkd>!apic
Apic@fffe0000ID:1(80050010)LogDesc:02000000DestFmt:ffffffffTPR41
TimeCnt:0be420e0clkSpurVec:1fFaultVec:e3error:0
IpiCmd:01000000`00040041Vec:41FixedDelDest=Selfedghigh
Timer..:00000000`000300fdVec:FDFixedDelDest=Selfedghighm
Linti0.:00000000`0001001fVec:1FFixedDelDest=Selfedghighm
Linti1.:00000000`000184ffVec:FFNMIDest=Selflvlhighm
TMR:63,73,A4,B1,B4
IRR:
ISR:
0:kd>!ioapic
IoApic@FEC00000ID:0(0)Arb:0
Inti00.:00000000`00000000Vec:00FixedDelPh:00000000edghigh
仅在windows2003上菜支持！Irql查看一个处理器的IRQL
lkd>!pcr
KPCRforProcessor0atffdff000:
Major1Minor1
NtTib.ExceptionList:ffffffff
NtTib.StackBase:805524f0
NtTib.StackLimit:8054f700
NtTib.SubSystemTib:00000000
NtTib.Version:00000000
NtTib.UserPointer:00000000
NtTib.SelfTib:00000000
SelfPcr:ffdff000
Prcb:ffdff120
Irql:00000000
IRR:00000000
IDR:ffffffff
InterruptMode:00000000
IDT:8003f400
GDT:8003f000
TSS:80042000
CurrentThread:8055ce60
NextThread:00000000
IdleThread:8055ce60
DpcQueue:
可以使用DDK上头文件中的ntddk.H定义的PCR和PRCB的信息。不幸的是在不适用延迟IRQL的系统上，比如本机器AMDAthlon64X26000+的windowsXPSP3上就不支持，因此为0，需要至少WINDOWS2003
http://msdn.microsoft.com/zh-cn/windows/hardware/gg463382
下载安装kernrates软件，进行内核性能剖析程序来分析性能。
C:\ProgramFiles\SupportTools>cd"c:\ProgramFiles\KrView\Kernrates"
C:\ProgramFiles\KrView\Kernrates>dir
驱动器C中的卷没有标签。
卷的序列号是18F6-A188
C:\ProgramFiles\KrView\Kernrates的目录
2012-02-0716:57
2012-02-0716:57
2003-11-0716:58269,312Kernrate_i386_Win2000.exe
2003-11-0716:58129,024Kernrate_i386_XP.exe
2003-11-0716:59326,656Kernrate_ia64_XP.exe
3个文件724,992字节
2个目录146,187,862,016可用字节
C:\ProgramFiles\KrView\Kernrates>Kernrate_i386_XP.exe
/==============================\
\==============================/
Date:2012/02/07Time:16:58:17
MachineName:AMD6000
NumberofProcessors:2
PROCESSOR_ARCHITECTURE:x86
PROCESSOR_LEVEL:15
PROCESSOR_REVISION:4303
PhysicalMemory:2816MB
PagefileTotal:2656MB
VirtualTotal:2047MB
PageFile1:(null),0MB
OSVersion:5.1Build2600Service-Pack:3.0
WinDir:C:\WINDOWS
KernrateUser-SpecifiedCommandLine:
Kernrate_i386_XP.exe
KernelProfile(PID=0):Source=Time,
UsingKernrateDefaultRateof25000events/hit
Startingtocollectprofiledata
***>Pressctrl-ctofinishcollectingprofiledata
------------OverallSummary:--------------
P0K0:00:08.562(8.8%)U0:00:11.109(11.4%)I0:01:17.703(79.8%)DPC
0:00:01.656(1.7%)Interrupt0:00:00.062(0.1%)
Interrupts=142334,InterruptRate=1462/sec.
P1K0:00:10.562(10.8%)U0:00:06.406(6.6%)I0:01:20.406(82.6%)DPC
0:00:05.828(6.0%)Interrupt0:00:00.265(0.3%)
Interrupts=73111,InterruptRate=751/sec.
TOTALK0:00:19.125(9.8%)U0:00:17.515(9.0%)I0:02:38.109(81.2%)DPC
0:00:07.484(3.8%)Interrupt0:00:00.328(0.2%)
TotalInterrupts=215445,TotalInterruptRate=2213/sec.
TotalProfileTime=97375msec
BytesStartBytesStopByt
esDiff.
AvailablePhysicalMemory,1864134656,2005221376,141086
720
AvailablePagefile(s),1864282112,2005024768,140742
656
AvailableVirtual,2131689472,2130640896,-1048
576
AvailableExtendedVirtual,0,0,
0
TotalAvg.Rate
ContextSwitches,571193,5866/sec.
SystemCalls,2132527,21900/sec.
PageFaults,325110,3339/sec.
I/OReadOperations,11188,115/sec.
I/OWriteOperations,8299,85/sec.
I/OOtherOperations,29196,300/sec.
I/OReadBytes,39124405,3497/I/O
I/OWriteBytes,16790740,2023/I/O
I/OOtherBytes,4785210,164/I/O
-----------------------------
ResultsforKernelMode:
-----------------------------
OutputResults:KernelModuleCount=142
PercentageinthefollowingtableisbasedontheTotalHitsfortheKernel
Time69611hits,25000eventsperhit--------
ModuleHitsmsec%TotalEvents/Sec
processr608559735987%15626444
ntkrnlpa4118973755%1057252
ati2cqag947973591%243172
hal907973751%232862
ati2dvag838973591%215182
PECKP701973591%180003
win32k654973590%167935
USBPORT130973590%33381
athuw81973590%20799
RtkHDAud38973590%9757
usbehci38973590%9757
ati2mtag37973590%9500
kmixer34973590%8730
tcpip30973590%7703
NDIS24973590%6162
Ntfs23973590%5905
afd21973590%5392
Npfs18973590%4622
portcls15973590%3851
l151x8613973590%3338
sptd13973590%3338
usbhub12973590%3081
wdf010009973590%2311
watchdog6973590%1540
fltMgr6973590%1540
ipnat5973590%1283
LiveKdD4973590%1027
avipbb4973590%1027
ati3duag3973590%770
ks3973590%770
avgntflt2973590%513
el90xbc52973590%513
usbohci2973590%513
wdmaud1973590%256
sniffer1973590%256
LMouFilt1973590%256
mouhid1973590%256
LHidFilt1973590%256
HIDPARSE1973590%256
avkmgr1973590%256
rdbss1973590%256
ipsec1973590%256
psched1973590%256
TDI1973590%256
av261r6u1973590%256
HDAudBus1973590%256
Mup1973590%256
CLASSPNP1973590%256
PartMgr1973590%256
PCIIDEX1973590%256
WMILIB1973590%256
=================================ENDOFRUN==================================
==============================NORMALENDOFRUN==============================
C:\ProgramFiles\KrView\Kernrates>
由此可见系统在内核模式下花了TOTALK0:00:19.125(9.8%)的时间。碰撞率最高的模块是process，这个是CPU处理器驱动程序。
在X86的多处理器系统上，IRQ本质上是随机的，但在X64或者IA64上，IRQ是16除中断向量号。
因为windows并没有以任何一种可控的方式对设备IRQ进行优先级处理，而且用户的应用程序只能在处理器的IRQL为被动级别的时候才能执行，所以windows不适合作实时系统。
声明：真相：windowsXPEmbedded并没有实时特性，而是借助venturcom公司将实时内核内嵌到自定义好的HAL中。