前一篇文章介绍了WinDbg入门，本篇主要介绍WinDbg常用命令和用法。 调试程序的CPU满载问题，关键是要知道程序当前正在进行什么操作。假如我们在cpu满载时创建了一个dump文件，使用下面几个命令可以查看当前程序正在进行什么处理：
.time
运行.time命令会显示时间相关的信息，如系统运行时间，进程运行时间和CPU花费在内核态和用户态的时间。
0:000> .time Debug session time: Tue Oct 23 08:38:35.000 2007 (GMT+1) System Uptime: 4 days 17:48:01.906 Process Uptime: 0 days 0:24:37.000 Kernel time: 0 days 0:04:23.000 User time: 0 days 0:03:28.000
你可以看到系统已正常运行超过4天，进程运行了24分钟，CPU在内核态和用户态累积使用了8分钟。根据进程时间和CPU时间能大概估算出CPU使用率平均值是32.5%。
!threadpool
通过!threadpool命令我们能准确知道创建dump时cpu的使用率。也能知道在队列中的待处理请求数，Completion Port(IOCP)线程数和定时器time数。
0:000> !threadpool CPU utilization 100% Worker Thread: Total: 5 Running: 4 Idle: 1 MaxLimit: 200 MinLimit: 2 Work Request in Queue: 16 Unknown Function: 6a2d945d Context: 023ede30 Unknown Function: 6a2d945d Context: 023ee1e8 AsyncTimerCallbackCompletion TimerInfo@11b53760 Unknown Function: 6a2d945d Context: 023ee3a8 Unknown Function: 6a2d945d Context: 023e3040 Unknown Function: 6a2d945d Context: 023ee178 Unknown Function: 6a2d945d Context: 023edfb0 AsyncTimerCallbackCompletion TimerInfo@11b36428 AsyncTimerCallbackCompletion TimerInfo@11b53868 Unknown Function: 6a2d945d Context: 023ee060 Unknown Function: 6a2d945d Context: 023ee290 Unknown Function: 6a2d945d Context: 023eded0 Unknown Function: 6a2d945d Context: 023edd88 Unknown Function: 6a2d945d Context: 023ede98 Unknown Function: 6a2d945d Context: 023ee258 Unknown Function: 6a2d945d Context: 023edfe8 -------------------------------------- Number of Timers: 9 -------------------------------------- Completion Port Thread:Total: 3 Free: 3 MaxFree: 4 CurrentLimit: 2 MaxLimit: 200 MinLimit: 2
我们可以看到当前CPU已100%使用率，我们进入下一命令。
!runaway
这个命令用于显示所有正在运行的线程和它们的CPU使用率。这个命令对于查找高CPU使用率问题很有帮助！
0:000> !runaway User Mode Time Thread Time 25:1a94 0 days 0:00:39.937 16:1bc0 0 days 0:00:38.390 50:1e8c 0 days 0:00:08.859 52:1e40 0 days 0:00:08.687 20:1c2c 0 days 0:00:08.234 51:1340 0 days 0:00:08.171 21:1bcc 0 days 0:00:06.953 26:13ec 0 days 0:00:06.671 44:131c 0 days 0:00:03.906 22:d8c 0 days 0:00:03.375 33:78c 0 days 0:00:02.656 34:1a8c 0 days 0:00:00.906 29:1f5c 0 days 0:00:00.828 6:e28 0 days 0:00:00.625 5:1c78 0 days 0:00:00.546 23:14a4 0 days 0:00:00.484 4:5ac 0 days 0:00:00.437 45:5dc 0 days 0:00:00.421 3:13b4 0 days 0:00:00.421 47:19c8 0 days 0:00:00.375 28:1b6c 0 days 0:00:00.250 46:1dac 0 days 0:00:00.156 7:1dd8 0 days 0:00:00.109 48:cdc 0 days 0:00:00.093 49:1eac 0 days 0:00:00.062 15:1a64 0 days 0:00:00.062 0:1804 0 days 0:00:00.046 36:4a4 0 days 0:00:00.031 11:1eb4 0 days 0:00:00.031 1:10b4 0 days 0:00:00.031 31:16ac 0 days 0:00:00.015 14:4ac 0 days 0:00:00.015 2:186c 0 days 0:00:00.015 59:590 0 days 0:00:00.000 58:294 0 days 0:00:00.000 57:16d0 0 days 0:00:00.000 56:1578 0 days 0:00:00.000 55:1428 0 days 0:00:00.000 54:16d8 0 days 0:00:00.000 53:fd8 0 days 0:00:00.000 43:1b8c 0 days 0:00:00.000 42:1c24 0 days 0:00:00.000 41:1e2c 0 days 0:00:00.000 40:11b0 0 days 0:00:00.000 39:edc 0 days 0:00:00.000 38:1a08 0 days 0:00:00.000 37:171c 0 days 0:00:00.000 35:1254 0 days 0:00:00.000 32:1f9c 0 days 0:00:00.000 30:1ae8 0 days 0:00:00.000 27:190c 0 days 0:00:00.000 24:1d2c 0 days 0:00:00.000 19:1e38 0 days 0:00:00.000 18:ee4 0 days 0:00:00.000 17:fb8 0 days 0:00:00.000 13:1b54 0 days 0:00:00.000 12:1a48 0 days 0:00:00.000 10:f64 0 days 0:00:00.000 9:1024 0 days 0:00:00.000 8:1b78 0 days 0:00:00.000
你可以看到运行线程的总时间和使用.time命令看到的总cpu使用时间并不相等。原因很简单，因为线程被重复使用或回收了。这也意味着一个线程的CPU使用时间可能是处理多个请求的结果。
!threads
!threads显示当前所有的托管线程信息。输出如下：
0:000> !threads
ThreadCount: 48
UnstartedThread: 0
BackgroundThread: 29
PendingThread: 0
DeadThread: 19
Hosted Runtime: no
PreEmptive GC Alloc Lock
ID OSID ThreadOBJ State GC Context Domain Count APT Exception
16 1 1bc0 001fccd0 1808220 Enabled 00000000:00000000 0019daf0 0 Ukn (Threadpool Worker)
22 2 d8c 002016f0 b220 Enabled 00000000:00000000 0019daf0 0 MTA (Finalizer)
14 4 4ac 00242e58 880a220 Enabled 00000000:00000000 0019daf0 0 MTA (Threadpool Completion Port)
23 5 14a4 11b39f18 80a220 Enabled 00000000:00000000 0019daf0 0 MTA (Threadpool Completion Port)
24 6 1d2c 11b41ad8 1220 Enabled 00000000:00000000 0019daf0 0 Ukn
25 7 1a94 11b46c70 180b220 Enabled 27240c98:27241fd8 11b42540 1 MTA (Threadpool Worker)
26 9 13ec 12ce2888 200b220 Enabled 2a9f1434:2a9f33c0 11b42540 0 MTA
27 a 190c 12d85eb8 200b220 Enabled 00000000:00000000 11b42540 0 MTA
29 b 1f5c 13df6a50 200b220 Enabled 2ab1da6c:2ab1f1c0 11b42540 0 MTA
30 c 1ae8 12d44a58 b220 Enabled 00000000:00000000 11b42540 0 MTA
31 d 16ac 12e2e008 200b220 Enabled 2a81348c:2a8153c0 11b42540 1 MTA
5 e 1c78 12da2160 220 Enabled 00000000:00000000 0019daf0 0 Ukn
33 8 78c 11b674c8 200b220 Enabled 2707b818:2707c1d8 11b42540 0 MTA
34 12 1a8c 13f163c8 220 Enabled 00000000:00000000 0019daf0 0 Ukn
36 13 4a4 13eef718 200b220 Enabled 2a7db4a4:2a7dd3c0 11b42540 0 MTA
4 14 5ac 13ef2008 220 Enabled 00000000:00000000 0019daf0 0 Ukn
42 10 1c24 13f0e950 880b220 Enabled 00000000:00000000 0019daf0 0 MTA (Threadpool Completion Port)
6 11 e28 13f16008 220 Enabled 00000000:00000000 0019daf0 0 Ukn
3 f 13b4 13eba008 220 Enabled 00000000:00000000 0019daf0 0 Ukn
43 15 1b8c 140db008 880b220 Enabled 00000000:00000000 0019daf0 0 MTA (Threadpool Completion Port)
44 17 131c 140ceb28 200b220 Enabled 272288c8:27229fd8 11b42540 0 MTA
45 1d 5dc 140cd0a0 220 Enabled 00000000:00000000 0019daf0 0 Ukn
47 20 19c8 1651a008 220 Enabled 00000000:00000000 0019daf0 0 Ukn
XXXX 24 0 16468880 1801820 Enabled 00000000:00000000 0019daf0 0 Ukn (Threadpool Worker)
46 1f 1dac 1650ab48 220 Enabled 00000000:00000000 0019daf0 0 Ukn
XXXX 1a 0 140d5008 1801820 Enabled 00000000:00000000 0019daf0 0 Ukn (Threadpool Worker)
XXXX 16 0 140c5008 1801820 Enabled 00000000:00000000 0019daf0 0 Ukn (Threadpool Worker)
50 3 1e8c 14064420 180b220 Enabled 27246f54:27247fd8 11b42540 1 MTA (Threadpool Worker)
XXXX 35 0 1406e800 1801820 Enabled 00000000:00000000 0019daf0 0 Ukn (Threadpool Worker)
51 36 1340 140df008 180b220 Enabled 2adec9cc:2aded1c0 11b42540 1 MTA (Threadpool Worker)
XXXX 37 0 16566868 1801820 Enabled 00000000:00000000 0019daf0 0 Ukn (Threadpool Worker)
48 38 cdc 16578840 220 Enabled 00000000:00000000 0019daf0 0 Ukn
XXXX 39 0 16566c28 1801820 Enabled 00000000:00000000 0019daf0 0 Ukn (Threadpool Worker)
XXXX 3b 0 1646b8b0 1801820 Enabled 00000000:00000000 0019daf0 0 Ukn (Threadpool Worker)
XXXX 3c 0 16674008 1801820 Enabled 00000000:00000000 0019daf0 0 Ukn (Threadpool Worker)
XXXX 3d 0 16676418 1801820 Enabled 00000000:00000000 0019daf0 0 Ukn (Threadpool Worker)
XXXX 3e 0 16676fb8 1801820 Enabled 00000000:00000000 0019daf0 0 Ukn (Threadpool Worker)
XXXX 3f 0 16674d48 1801820 Enabled 00000000:00000000 0019daf0 0 Ukn (Threadpool Worker)
XXXX 40 0 1667de10 1801820 Enabled 00000000:00000000 0019daf0 0 Ukn (Threadpool Worker)
XXXX 41 0 16680050 1801820 Enabled 00000000:00000000 0019daf0 0 Ukn (Threadpool Worker)
XXXX 42 0 166812e8 1801820 Enabled 00000000:00000000 0019daf0 0 Ukn (Threadpool Worker)
XXXX 43 0 16683e60 1801820 Enabled 00000000:00000000 0019daf0 0 Ukn (Threadpool Worker)
52 44 1e40 165259e8 180b220 Enabled 2adf126c:2adf31c0 11b42540 1 MTA (Threadpool Worker)
XXXX 45 0 165b7c08 1801820 Enabled 00000000:00000000 0019daf0 0 Ukn (Threadpool Worker)
XXXX 46 0 165aa3d8 1801820 Enabled 00000000:00000000 0019daf0 0 Ukn (Threadpool Worker)
XXXX 47 0 165242c8 1801820 Enabled 00000000:00000000 0019daf0 0 Ukn (Threadpool Worker)
XXXX 48 0 165e9500 1801820 Enabled 00000000:00000000 0019daf0 0 Ukn (Threadpool Worker)
49 3a 1eac 165676f0 220 Enabled 00000000:00000000 0019daf0 0 Ukn
线程ID为XXXX表示该线程已结束，并在等待回收。我们也能看到线程ID为22的线程正在终结(finalizer)。假如我们使用!runaway命令时看到22线程有大量的cpu活动，可能我们的程序有终结(finalizer)问题。
切换到指定线程
要切换到指定的线程，可以使用下面的格式命令：~[thread id]s，假如我们要切换到50线程，命令如下：
0:000> ~50s
现在我们已切换到线程50，可以使用很多其他有用的命令。
!clrstack
!clrstack显示当前线程的堆栈信息，通过指定“-p”参数，还能看到方法调用的参数和局部变量信息。 下面是线程50的堆栈信息：
0:050> !clrstack OS Thread Id: 0x1e8c (50) ESP EIP 17a9e750 7d61c828 [NDirectMethodFrameSlim: 17a9e750] System.DirectoryServices.Protocols.Wldap32.ldap_bind_s(IntPtr, System.String, System.DirectoryServices.Protocols.SEC_WINNT_AUTH_IDENTITY_EX, System.DirectoryServices.Protocols.BindMethod) 17a9e768 14df70f9 System.DirectoryServices.Protocols.LdapConnection.BindHelper(System.Net.NetworkCredential, Boolean) 17a9e794 14df6de0 System.DirectoryServices.Protocols.LdapConnection.Bind() 17a9e79c 14df59e9 System.DirectoryServices.Protocols.LdapConnection.SendRequestHelper(System.DirectoryServices.Protocols.DirectoryRequest, Int32 ByRef) 17a9e8b8 14df56e8 System.DirectoryServices.Protocols.LdapConnection.SendRequest(System.DirectoryServices.Protocols.DirectoryRequest, System.TimeSpan) 17a9e8bc 14df5657 [InlinedCallFrame: 17a9e8bc]
从下向上看，我们能知道LdapConnection调用了SendRequest方法，而SendRequest又调用了SendRequestHelper方法等等。 如果我们执行“!clrstack -p”命令，我们得到信息：
0:050> !clrstack -p
OS Thread Id: 0x1e8c (50)
ESP EIP
17a9e750 7d61c828 [NDirectMethodFrameSlim: 17a9e750] System.DirectoryServices.Protocols.Wldap32.ldap_bind_s(IntPtr, System.String, System.DirectoryServices.Protocols.SEC_WINNT_AUTH_IDENTITY_EX, System.DirectoryServices.Protocols.BindMethod)
17a9e768 14df70f9 System.DirectoryServices.Protocols.LdapConnection.BindHelper(System.Net.NetworkCredential, Boolean)
PARAMETERS:
this = 0x271fdfe0
newCredential =
needSetCredential =
17a9e794 14df6de0 System.DirectoryServices.Protocols.LdapConnection.Bind()
PARAMETERS:
this =
17a9e79c 14df59e9 System.DirectoryServices.Protocols.LdapConnection.SendRequestHelper(System.DirectoryServices.Protocols.DirectoryRequest, Int32 ByRef)
PARAMETERS:
this = 0x271fdfe0
request = 0x27246e38
messageID = 0x17a9e8ec
17a9e8b8 14df56e8 System.DirectoryServices.Protocols.LdapConnection.SendRequest(System.DirectoryServices.Protocols.DirectoryRequest, System.TimeSpan)
PARAMETERS:
this = 0x271fdfe0
request = 0x27246e38
requestTimeout =
17a9e8bc 14df5657 [InlinedCallFrame: 17a9e8bc]
我们可以看到DirectoryRequest参数传递给了SendRequest和SendRequestHelper，要查看DirectoryRequest的相关信息，我们只需复制它的地址（0x27246e38），并在下个命令中使用。
!dumpobject (!do)
这是另外一个重要的命令。Dumpobject会打印出指定地址的对象的相关信息。我们使用刚才的地址试下:
0:050> !do 0x27246e38
Name: System.DirectoryServices.Protocols.SearchRequest
MethodTable: 14b394c4
EEClass: 14d97ce0
Size: 52(0x34) bytes
GC Generation: 0
(C:\WINDOWS\assembly\GAC_MSIL\System.DirectoryServices.Protocols\2.0.0.0__b03f5f7f11d50a3a\System.DirectoryServices.Protocols.dll)
Fields:
MT Field Offset Type VT Attr Value Name
02c39310 4000102 4 System.String 0 instance 00000000 directoryRequestID
14b398bc 4000103 8 ...ControlCollection 0 instance 27246e90 directoryControlCollection
02c39310 4000111 c System.String 0 instance 27246d00 dn
12579f5c 4000112 10 ....StringCollection 0 instance 27246eb4 directoryAttributes
02c36ca0 4000113 14 System.Object 0 instance 27246ddc directoryFilter
14b39344 4000114 18 System.Int32 1 instance 1 directoryScope
14b393fc 4000115 1c System.Int32 1 instance 0 directoryRefAlias
0fd3da00 4000116 20 System.Int32 1 instance 0 directorySizeLimit
1202af88 4000117 28 System.TimeSpan 1 instance 27246e60 directoryTimeLimit
120261c8 4000118 24 System.Boolean 1 instance 0 directoryTypesOnly
通过打印的信息，可以知道它是System.DirectoryServices.Protocols.SearchRequest的一个对象，而显示的都是 System.DirectoryServices.Protocols.SearchRequest的属性值。要知道SearchRequest类的相关属性信息，可以查看MSDN。当前我们已有RequestId, Scope和DistinguishedName等等。 所以，假如我们想知道SearchRequest对象的DistinguishedName属性值，即是上面列表中的dn，我们只需再复制它的地址（27246d00），并再次使用!dumpobject命令。因为DistinguishedName是System.String类型，所以输出结果很明显：
0:050> !do 27246d00
Name: System.String
MethodTable: 02c39310
EEClass: 0fb610ac
Size: 112(0x70) bytes
GC Generation: 0
(C:\WINDOWS\assembly\GAC_32\mscorlib\2.0.0.0__b77a5c561934e089\mscorlib.dll)
String: CN=Dummy,CN=Accounts,CN=useradm,DC=dummy,DC=net
Fields:
MT Field Offset Type VT Attr Value Name
0fd3da00 4000096 4 System.Int32 1 instance 48 m_arrayLength
0fd3da00 4000097 8 System.Int32 1 instance 47 m_stringLength
0fb80010 4000098 c System.Char 1 instance 43 m_firstChar
02c39310 4000099 10 System.String 0 shared static Empty
>> Domain:Value 0019daf0:03380310 11b42540:03380310 << 0fb86d44 400009a 14 System.Char[] 0 shared static WhitespaceChars >> Domain:Value 0019daf0:03380324 11b42540:033855bc <<
通过输出的信息我们很容易知道DistinguishedName属性的值是“CN=Dummy,CN=Accounts,CN=useradm,DC=dummy,DC=net”。如果我们想查看更多内容，只需继续使用!dumpobject命令即可。
!dumpstackobjects (!dso)
使用该命令我们可以查看到当前线程的堆栈引用的所有托管对象。打印信息如下：
0:050> !dso OS Thread Id: 0x1e8c (50) ESP/REG Object Name 17a9e534 0741f860 System.RuntimeType 17a9e6b8 271fdfe0 System.DirectoryServices.Protocols.LdapConnection 17a9e6bc 27246f20 System.DirectoryServices.Protocols.SEC_WINNT_AUTH_IDENTITY_EX 17a9e740 271fdfe0 System.DirectoryServices.Protocols.LdapConnection 17a9e744 27246f20 System.DirectoryServices.Protocols.SEC_WINNT_AUTH_IDENTITY_EX 17a9e764 27246f20 System.DirectoryServices.Protocols.SEC_WINNT_AUTH_IDENTITY_EX 17a9e768 271fdfe0 System.DirectoryServices.Protocols.LdapConnection 17a9e780 271fdfe0 System.DirectoryServices.Protocols.LdapConnection 17a9e784 27246e38 System.DirectoryServices.Protocols.SearchRequest 17a9e794 271fdf14 System.DirectoryServices.Protocols.LdapDirectoryIdentifier 17a9e7a8 27246ef8 System.Collections.ArrayList 17a9e7bc 27246ef8 System.Collections.ArrayList 17a9e7c8 271fdfe0 System.DirectoryServices.Protocols.LdapConnection 17a9e8a4 27246e38 System.DirectoryServices.Protocols.SearchRequest 17a9e8d0 27246ed8 System.Object[] (System.Object[]) 17a9e8e0 073ff6b8 System.String cn 17a9e8e4 271fdfe0 System.DirectoryServices.Protocols.LdapConnection 17a9e8f4 27246d00 System.String CN=Dummy,CN=Accounts,CN=useradm,DC=Dummy,DC=net 17a9e8f8 271fdfe0 System.DirectoryServices.Protocols.LdapConnection 17a9e8fc 27246e38 System.DirectoryServices.Protocols.SearchRequest 17a9e910 03380310 System.String 17a9e914 27246e24 System.Object[] (System.String[]) 17a9e918 272399a8 System.String CN=OID-Dummy-ABC123,CN=Dummy,CN=Accounts,CN=useradm,DC=Dummy,DC=net 17a9e91c 27246ddc System.String (CN=OID-Dummy-ABC123) ...etc...
这个命令对于查找当前线程引用了那些对象很有用。假如你想查看某一对象，只需复制[Object]字段的地址，并使用 !dumpobject命令：
0:050> !do 271fdfe0
Name: System.DirectoryServices.Protocols.LdapConnection
MethodTable: 14a2040c
EEClass: 149daf08
Size: 56(0x38) bytes
(C:\WINDOWS\assembly\GAC_MSIL\System.DirectoryServices.Protocols\2.0.0.0__b03f5f7f11d50a3a\System.DirectoryServices.Protocols.dll)
Fields:
MT Field Offset Type VT Attr Value Name
14a2078c 40000c3 4 ...NetworkCredential 0 instance 00000000 directoryCredential
14a2144c 40000c4 8 ...ificateCollection 0 instance 271fe018 certificatesCollection
1202af88 40000c5 10 System.TimeSpan 1 instance 271fdff0 connectionTimeOut
1466fe50 40000c6 c ...rectoryIdentifier 0 instance 271fdf14 directoryIdentifier
14a2034c 4000236 24 System.Int32 0 instance 2 connectionAuthType
14a223a4 4000237 18 ...dapSessionOptions 0 instance 271fe2d8 options
0fb896d8 4000238 28 System.IntPtr 0 instance 564180944 ldapHandle
120261c8 4000239 2c System.Boolean 0 instance 0 disposed
120261c8 400023a 2d System.Boolean 0 instance 0 bounded
120261c8 400023b 2e System.Boolean 0 instance 0 needRebind
14a22084 400023e 1c ...pResponseCallback 0 instance 271fe03c fd
120261c8 4000243 2f System.Boolean 0 instance 0 setFQDNDone
120261c8 4000244 30 System.Boolean 0 instance 1 automaticBind
120261c8 4000245 31 System.Boolean 0 instance 1 needDispose
120261c8 4000246 32 System.Boolean 0 instance 1 connected
14a2267c 4000247 20 ...s.QUERYCLIENTCERT 0 instance 271fe394 clientCertificateRoutine
0fd314bc 400023c 20 ...ections.Hashtable 0 shared static handleTable
>> Domain:Value 0019daf0:NotInit 11b42540:073fe504 < <
02c36ca0 400023d 24 System.Object 0 shared static objectLock
>> Domain:Value 0019daf0:NotInit 11b42540:073fe53c < <
0fd314bc 400023f 28 ...ections.Hashtable 0 shared static asyncResultTable
>> Domain:Value 0019daf0:NotInit 11b42540:073fe610 < <
14a21864 4000240 2c ...lResultsProcessor 0 shared static partialResultsProcessor
>> Domain:Value 0019daf0:NotInit 11b42540:073fe678 < <
12305e94 4000241 30 ....ManualResetEvent 0 shared static waitHandle
>> Domain:Value 0019daf0:NotInit 11b42540:073fe64c < <
14a21954 4000242 34 ...lResultsRetriever 0 shared static retriever
>> Domain:Value 0019daf0:NotInit 11b42540:073fe6a8 < <
!dumparray (!da)
你可能已经注意到有很多对象数组在堆栈中，在上面的列表中查找System.Object[]类型就能找到。如果你对对象数组使用 !dumpobject命令，你只能看到数组信息，而不能看到数组的内容信息，要看到数组内容信息，就需要使用!dumparray命令，或简称!da:
0:050> !do 27239b98 Name: System.Object[] MethodTable: 02c3896c EEClass: 02c388ec Size: 24(0x18) bytes Array: Rank 1, Number of elements 2, Type CLASS Element Type: System.String Fields: None 0:050> !da 27239b98 Name: System.String[] MethodTable: 02c3896c EEClass: 02c388ec Size: 24(0x18) bytes Array: Rank 1, Number of elements 2, Type CLASS Element Methodtable: 02c39310 [0] 272399a8 [1] 27239a44
通过!dumparray命令我们能知道该数组对象是字符串数组，并给出了数组项的地址。再使用!dumpobject命令我们就能看到数组项的具体内容。 !objsize 如果你查看上面打印的信息，可以看到对象的大小是24字节。从某方面来说，这是对的，24字节是System.Object[]数组对象本身大小，但并不包括数组内容的大小!要获得整个对象的大小，就要使用到 !objsize命令:
0:050> !objsize 27239b98 sizeof(27239b98) = 348 ( 0x15c) bytes (System.Object[])
!objsize会遍历对象引用的所有子对象，并计算出总的大小。如上面数组对象和它的内容的总大小是348字节。 如果对象有引用很多子对象，那么!objsize会花费较多的时间计算出总大小。
!dumpheap
这是另一个较频繁使用的命令。!dumpheap会打印出所有在托管堆中的对象信息。直接执行该命令会打印出大量的信息，所以一般使用时都至少带上一个参数。加上-stat参数后会输出总结后的信息，如下面是截取的是!dumpheap -stat命令输出的一部分:
0:050> !dumpheap -stat ------------------------------ Heap 0 total 2754508 objects ------------------------------ Heap 1 total 2761329 objects ------------------------------ total 5515837 objects Statistics: MT Count TotalSize Class Name 16e0a6d8 1 12 System.Collections.Generic.ObjectEqualityComparer`1[[System.Data.ProviderBase.DbConnectionInternal, System.Data]] 16d9cd9c 1 12 System.Xml.Serialization.Configuration.DateTimeSerializationSection+DateTimeSerializationMode 16d9bf30 1 12 System.Diagnostics.OrdinalCaseInsensitiveComparer 16d9112c 1 12 System.Xml.Serialization.NameTable 16d7f664 1 12 System.Xml.Serialization.TempAssemblyCache 163ea85c 1 12 System.Data.Res 1501e4c4 1 12 System.Collections.Generic.ObjectEqualityComparer`1[[System.Web.UI.Control, System.Web]] 14efb138 1 12 System.Net.TimeoutValidator 14ef9964 1 12 System.Net.Cache.HttpRequestCacheLevel 14ef77a8 1 12 Microsoft.Win32.WinInetCache 14ef68e4 1 12 System.Net.WebRequest+WebProxyWrapper 14ef658c 1 12 System.Net.Configuration.ProxyElement+BypassOnLocalValues 14ef63d8 1 12 System.Net.Configuration.ProxyElement+AutoDetectValues 14ef5b68 1 12 System.Net.CaseInsensitiveAscii 14ef5610 1 12 System.Net.HeaderInfoTable 14ef4718 1 12 System.Net.HttpRequestCreator 14db6710 1 12 System.Web.Configuration.MachineKeyValidationConverter 14db3140 1 12 System.Collections.Generic.ObjectEqualityComparer`1[[System.Runtime.Serialization.MemberHolder, mscorlib]] 14b3f4d8 1 12 System.Web.UI.SupportsEventValidationAttribute ...etc... 14a276a8 19578 704808 System.DirectoryServices.Interop.AdsValueHelper 14a2ea24 9196 735680 System.Web.UI.WebControls.Label 14a2e51c 16862 741928 System.Web.UI.WebControls.Style 125778ec 48015 768240 System.Collections.Specialized.NameObjectCollectionBase+NameObjectEntry 120261c8 65842 790104 System.Boolean 14a2ee7c 9198 809424 System.Web.UI.WebControls.Table 14b311c4 9647 810348 System.Web.UI.WebControls.Image 13a2b7dc 34913 837912 System.Web.HttpServerVarsCollectionEntry 14b303a4 10605 848400 System.Web.UI.WebControls.HyperLink 14d8e3d4 77748 932976 Microsoft.Web.UI.WebControls.BaseChildNodeCollection+ActionType 14db90ac 81372 976464 System.Web.UI.WebControls.FontInfo 14b30694 28648 1031328 System.Web.UI.WebControls.TableRow+CellControlCollection 14d8fdbc 38912 1089536 Microsoft.Web.UI.WebControls.TreeNodeCollection 14b3d0bc 86592 1385472 System.Web.UI.Pair 1466c5c4 39305 1414980 System.Web.UI.ControlCollection 14d8e48c 77748 1865952 Microsoft.Web.UI.WebControls.BaseChildNodeCollection+Action 1545061c 38874 2176944 Microsoft.Web.UI.WebControls.TreeNode 14b30eec 52668 2317392 System.Web.UI.WebControls.TableItemStyle 14a2f804 28515 2395260 System.Web.UI.WebControls.TableRow 14a2be6c 40894 2453640 System.Web.UI.LiteralControl 0fd3da00 228792 2745504 System.Int32 14b3e3ac 244793 2937516 System.Web.UI.IndexedString 14a2de94 198580 3177280 System.Web.UI.StateBag 1466c454 80512 3542528 System.Web.UI.Control+OccasionalFields 12302c2c 205849 4116980 System.Collections.Specialized.HybridDictionary 14b30024 52934 4446456 System.Web.UI.WebControls.TableCell 12302f2c 178294 4992232 System.Collections.Specialized.ListDictionary 14a2e284 412762 6604192 System.Web.UI.StateItem 14d8ce64 117078 7024680 Microsoft.Web.UI.WebControls.CssCollection 0fd314bc 132065 7395640 System.Collections.Hashtable 1230319c 422580 8451600 System.Collections.Specialized.ListDictionary+DictionaryNode 1202a58c 380438 9130512 System.Collections.ArrayList 0fd32050 133000 22582944 System.Collections.Hashtable+bucket[] 02c3896c 649842 23275900 System.Object[] 0fd3c12c 3471 36385536 System.Byte[] 001fee20 338 65409920 Free 02c39310 683083 161821000 System.String Total 5515837 objects Fragmented blocks larger than 0.5 MB: Addr Size Followed by 2adf31cc 2.0MB 2aff85d8 System.String 2b006a2c 20.3MB 2c4530d8 System.Net.SocketAddress
输出信息按对象类型的总大小升序排序，你一般可以在列表的最下面找到string对象的大小，因为字符串在程序中一般是最常用的。 其他比较有用的参数是-type和-mt（MethodTable的意思）。使用它们你可以查看指定对象类型的详细信息，例如假如我们想查看System.Net.HttpRequestCreator类型的具体信息，可以复制上面列表中它的MT字段地址（14ef4718），然后使用 !dumpheap -mt命令：
0:050> !dumpheap -mt 14ef4718
------------------------------
Heap 0
Address MT Size
0342ccf8 14ef4718 12
total 1 objects
------------------------------
Heap 1
Address MT Size
total 0 objects
------------------------------
total 1 objects
Statistics:
MT Count TotalSize Class Name
14ef4718 1 12 System.Net.HttpRequestCreator
上面列出了所有System.Net.HttpRequestCreator类型的对象的地址，假如我们想查看指定对象的信息，再使用!dumpobject命令就可以了。 !dumpheap -type可以根据字符串来匹配对应的对象类型。如我们输入命令“!dumpheap -type System.Web”，是指显示所有类名包含有“System.Web”字符串的对象信息。 其他参数-min和-max是接受表示对象大小的最大值和最小值（单位字节），命令会只列出大于指定值或小于指定值的对象信息。这两个参数对于查找滥用字符串问题很有帮助。
实战训练
查明缓存使用的大小
为了知道在System.Web.Caching.Cache类型中有多少数据，我执行了“ !dumpheap -stat -type System.Web.Caching.Cache”命令。注意，我用了-stat参数，否则我会得到一个包含有System.Web.Caching.CacheKeys和System.Web.Caching.CacheEntrys对象的很长的列表。下面的执行结果：
0:050> !dumpheap -type System.Web.Caching.Cache -stat
------------------------------
Heap 0
total 665 objects
------------------------------
Heap 1
total 1084 objects
------------------------------
total 1749 objects
Statistics:
MT Count TotalSize Class Name
123056f8 1 12 System.Web.Caching.CacheKeyComparer
1230494c 1 12 System.Web.Caching.Cache
1230500c 1 24 System.Web.Caching.CacheMultiple
1230514c 1 32 System.Web.Caching.CacheMemoryStats
123053b4 1 36 System.Web.Caching.CacheMemoryTotalMemoryPressure
123059bc 2 40 System.Web.Caching.CacheUsage
12304bdc 1 48 System.Web.Caching.CacheCommon
123054f4 1 52 System.Web.Caching.CacheMemoryPrivateBytesPressure
12305874 2 64 System.Web.Caching.CacheExpires
12304e64 2 200 System.Web.Caching.CacheSingle
1255b594 85 1360 System.Web.Caching.CacheDependency+DepFileInfo
123046c4 40 1440 System.Web.Caching.CacheDependency
123042ec 47 1504 System.Web.Caching.CacheItemRemovedCallback
123063fc 832 16640 System.Web.Caching.CacheKey
12306820 732 52704 System.Web.Caching.CacheEntry
Total 1749 objects
很明显System.Web.Caching.Cache的方法列表地址（MethodTable）是1230494c，再使用!dumpheap命令我就能看到它的所有对象信息，如下：
0:050> !dumpheap -mt 1230494c
------------------------------
Heap 0
Address MT Size
03392d20 1230494c 12
total 1 objects
------------------------------
Heap 1
Address MT Size
total 0 objects
------------------------------
total 1 objects
Statistics:
MT Count TotalSize Class Name
1230494c 1 12 System.Web.Caching.Cache
Total 1 objects
可以看到System.Web.Caching.Cache类型只有一个对象，地址是03392d20，再通过!objsize命令就能计算出它的大小。因为缓存对象很复杂，并包含有大量的子对象，要计算出总大小需要花些时间：
0:050> !objsize 03392d20 sizeof(03392d20) = 266640828 ( 0xfe49dbc) bytes (System.Web.Caching.Cache)
所以缓存的总大小是 266 MB。
缓存了什么东西？
为了弄清缓存中保存了什么内容，我查看了System.Web.Caching.CacheEntry的对象信息。通过之前的信息可以知道System.Web.Caching.CacheEntry类型的方法列表(MethodTable)是12306820。执行!dumpheap命令取CacheEntry的所有对象信息：
0:050> !dumpheap -mt 12306820 ------------------------------ Heap 0 Address MT Size 033950bc 12306820 72 033a20d8 12306820 72 033ac79c 12306820 72 033da21c 12306820 72 033f04c4 12306820 72 03428ec8 12306820 72 0344dab4 12306820 72 03815d00 12306820 72 038265d8 12306820 72 ....etc... 03af7010 12306820 72 03b291bc 12306820 72 03b2c674 12306820 72 03b6dca0 12306820 72 03b797dc 12306820 72 03b85318 12306820 72 03ba9150 12306820 72 03c258cc 12306820 72 03de43c8 12306820 72 03e160f8 12306820 72 total 382 objects ------------------------------ total 732 objects
要显示上面的信息，也可以使用“!dumpheap -type System.Web.Caching.CacheEntry”命令。 有了所有CacheEntry对象的地址信息，我随机拿了一个地址查看它的内容：
0:050> !do 03b2c674
Name: System.Web.Caching.CacheEntry
MethodTable: 12306820
EEClass: 122f6470
Size: 72(0x48) bytes
(C:\WINDOWS\assembly\GAC_32\System.Web\2.0.0.0__b03f5f7f11d50a3a\System.Web.dll)
Fields:
MT Field Offset Type VT Attr Value Name
02c39310 4001327 4 System.String 0 instance 03b2c600 _key
0fb8f1f8 4001328 c System.Byte 0 instance 2 _bits
0fd3da00 4001329 8 System.Int32 0 instance -1314181915 _hashCode
02c36ca0 4001330 10 System.Object 0 instance 03b2c644 _value
120219d0 4001331 1c System.DateTime 1 instance 03b2c690 _utcCreated
120219d0 4001332 24 System.DateTime 1 instance 03b2c698 _utcExpires
1202af88 4001333 2c System.TimeSpan 1 instance 03b2c6a0 _slidingExpiration
0fb8f1f8 4001334 d System.Byte 0 instance 7 _expiresBucket
123062d8 4001335 34 ...g.ExpiresEntryRef 1 instance 03b2c6a8 _expiresEntryRef
0fb8f1f8 4001336 e System.Byte 0 instance 4294967295 _usageBucket
12306738 4001337 38 ...ing.UsageEntryRef 1 instance 03b2c6ac _usageEntryRef
120219d0 4001338 3c System.DateTime 1 instance 03b2c6b0 _utcLastUpdate
123046c4 4001339 14 ...g.CacheDependency 0 instance 00000000 _dependency
02c36ca0 400133a 18 System.Object 0 instance 033d8344 _onRemovedTargets
120219d0 400132d 1bc System.DateTime 1 shared static NoAbsoluteExpiration
>> Domain:Value 0019daf0:NotInit 11b42540:03395104 < <
1202af88 400132e 1c0 System.TimeSpan 1 shared static NoSlidingExpiration
>> Domain:Value 0019daf0:NotInit 11b42540:03395114 < <
1202af88 400132f 1c4 System.TimeSpan 1 shared static OneYear
>> Domain:Value 0019daf0:NotInit 11b42540:03395124 < <
输出的是CacheEntry的属性信息，里面最重要的是_value属性。我复制它的地址（03b2c644），再用!dumpobject命令查看：
0:000> !do 03e160c8
Name: System.Web.SessionState.InProcSessionState
MethodTable: 14dbad5c
EEClass: 14e43af8
Size: 48(0x30) bytes
(C:\WINDOWS\assembly\GAC_32\System.Web\2.0.0.0__b03f5f7f11d50a3a\System.Web.dll)
Fields:
MT Field Offset Type VT Attr Value Name
1466c9d8 4001d89 4 ...ateItemCollection 0 instance 1a7f5438 _sessionItems
1292672c 4001d8a 8 ...ObjectsCollection 0 instance 00000000 _staticObjects
0fd3da00 4001d8b c System.Int32 0 instance 20 _timeout
120261c8 4001d8c 18 System.Boolean 0 instance 0 _locked
120219d0 4001d8d 1c System.DateTime 1 instance 03e160e4 _utcLockDate
0fd3da00 4001d8e 10 System.Int32 0 instance 1 _lockCookie
1202bf60 4001d8f 24 ...ReadWriteSpinLock 1 instance 03e160ec _spinLock
0fd3da00 4001d90 14 System.Int32 0 instance 0 _flags
可以看到缓存的是一个InProcSessionState对象。
参考文章： Getting started with windbg - part I Getting started with windbg - part II