SOS Commands

I started to use SOS commands one year ago while reading Production Debugging for .NET Framework Applications. I also used SOS commands to investigate my own apps ten months ago. I was quite familar with SOS commands then. But I almost forget SOS commands completely now. I'd like to make a list of SOS commands commonly used so that I can use them later. The commands listed below are stolen from both Drill Into .NET Framework Internals to See How the CLR Creates Runtime Objects and Production Debugging for .NET Framework Applications.

Before you load SOS into the process, enable unmanaged code debugging from the project properties in Visual Studio .NET. Add the directory in which SOS.dll is located to the PATH environment variable.

Now you can start your VS debugging process. Then open Debug Windows Immediate. In the immediate window, you can execute SOS commands.

To load SOS.dll (You must do this before you execute any SOS commands),
.load sos.dll

Use !help to get a list of debugger commands.

!DumpDomain

//DumpHeap allows listing of all the heap contents and all the instances of a particular
// type
!DumpHeap -type SimpleClass

// DumpObj dumps the contents of an instance
!DumpObj 0x00a8197c

// ObjSize dumps the space taken up by the instance
// ObjSize will not include the memory taken up by the syncblk infrastructure
// In the .NET Framework 1.1, the CLR is not aware of the memory taken up by any
// unmanaged resources like GDI objects, COM objects, file handles, and so on
!ObjSize 0x00a8197c

// disassemble an address
!u 0x00955263

// dump a method table
!DumpMT -MD 0x9552a0

// dump a method descritor
!DumpMD 0x00955268

// find the addresses of EEClass and MethodTable for MyClass
// The first argument to Name2EE is the module name
// that can be obtained from DumpDomain command.
!Name2EE C:\Working\test\ClrInternals\Sample1.exe MyClass

!DumpClass 02ca3508

// examine the GC heap size
!eeheap -gc

!dumpheap -stat

!gcroot 17b90018