getting visual studio ultimate “Debug Managed Memo

Question

Is it possible to obtain summary information for managed objects on the heap in WINDBG that's similar to the summary presented by Visual Studio Ultimate's 'Debug Managed Memory' option.

I can obtain some of the information, but it's on a case by case basis, and is quite tedious. Is there a macro or set of commands that can produce similar output using WINDBG?

Visual Studio seems to have a neat little routine where it collects all the roots and shows a summary of the root object classes and their total memory.

Answer 1

These would get you the managed Memory, Heap Summary and Heap Consumption for specific types and just in case you are trying to find strings on the heap:

!EEHeap
!DumpHeap -stat 
!DumpHeap -strings 
!DumpHeap -Type <TypeSpec> 

This will let you have a bin file which can be used in CLRProfiler:

!traverseheap

For more refer to SOS Help. sosex is another extension but I not used it to debug leaks. CLRProfiler and Visual Studio Standalone Profiler are the best tools to debug these issues than Windbg IMHO.

Answer 2

Like for any .NET issue, you'll first need the SOS extension

.loadby sos clr; .loadby sos mscorwks

You can then get a list of objects using

!dumpheap -stat; * Statistics output, good if you don't know what you're looking for
!dumpheap -type <SubstringOfClass>; * If you know what type you're after
!dumpheap -mt <MethodTable>; * If the class substring is not unique enough

To get the inclusive size, you can use

!objsize <address>

To find the root of an object, use

!gcroot <address>

Note that IMHO there is no convenient way of showing all root objects.

I'm not sure if Visual Studio lists objects on the stack. In WinDbg this would be

~*e !dso

Example walkthrough:

0:005> !dumpheap -stat
Statistics:
              MT    Count    TotalSize Class Name
000007fef2611ec8        1           24 System.Collections.Generic.ObjectEqualityComparer`1[[System.Runtime.Serialization.MemberHolder, mscorlib]]
...
000007fef2622968        1           64 System.BaseConfigHandler+CreateAttributeCallback
...
000007fef25fa690      396       117910 System.Byte[]
000007fef25a4458     1570       227560 System.Object[]
000007fef25f6508     3300       234762 System.String
Total 17883 objects

0:005> !dumpheap -stat -type Handler
Statistics:
              MT    Count    TotalSize Class Name
000007fef2622968        1           64 System.BaseConfigHandler+CreateAttributeCallback
000007fef26228b0        1           64 System.BaseConfigHandler+CreateNodeCallback
000007fef26227f8        1           64 System.BaseConfigHandler+ErrorCallback
Total 3 objects

0:005> !dumpheap -mt 000007fef2622968
         Address               MT     Size
0000000002594848 000007fef2622968       64     

Statistics:
              MT    Count    TotalSize Class Name
000007fef2622968        1           64 System.BaseConfigHandler+CreateAttributeCallback
Total 1 objects

0:005> !objsize 0000000002594848 
sizeof(0000000002594848) = 168728 (0x29318) bytes (System.BaseConfigHandler+CreateAttributeCallback)

0:005> !gcroot 0000000002594848 
Found 0 unique roots (run '!GCRoot -all' to see all roots).

0:005> !gcroot -all 0000000002594848 
Found 0 roots.

So it seems that this object has no more references and will be garbage collected during next GC.

0:001> !dso
OS Thread Id: 0xb2c (1)
RSP/REG          Object           Name
00000000024B0000 00000000024b1048 System.Exception