How to Instrument a Unit Test DLL for performance profiling in VS 2008

This tutorial will show how to instrument a unit test DLL for performance profiling. Visual Studio will allow you to do performance profiling on individual tests (i.e. functions) in a test suite. This can be done in the user interface (i.e. UI or IDE). However if you have a unit test DLL that contains lots of unit tests or test methods, it’s apparently not possible to do performance profiling in the IDE.

Here was my original question:

 Question on MSDN forums

I have a MS Unit Test DLL written in C# that targets a C++/CLI managed assembly. I have roughly 60 unit tests in that unit test dll. What I would like to do is run all the unit tests under the performance profiler, in the IDE. That is using the performance explorer to run a performance session for all the unit tests in my test DLL. I know how to do this from the command line, but I feel that is a last resort. I’d like to do this in the IDE if possible. It is possible to create a performance session for one unit test in the unit test DLL. The steps are listed here: ms-help://MS.VSCC.v90/MS.MSDNQTR.v90.en/dv_vsetlt01/html/4cc514d2-47bd-4f1c-a039-5ffae7c68bf1.htm i.e. Right click over a test result, and select "Create Performance Session". Whereupon the Performance Explorer will show a new session based off of one unit test. That’s great, but I’ve got 60 unit tests in my DLL. I don’t want to have to create 60 performance sessions.


Build the code that you will be testing. In my case it was the following DLL’s (Assuming a common root folder)

DLL name


..ManagedAPIWin32DebugUnderstandWrapper.ManagedAPI.dl The DLL with the code I wanted to test
..UnitTestbinx86DebugUnitTest.dll This DLL contains my unit tests

Then just to play it safe, run all the unit tests (This can be done in the IDE) in UnitTest.dll. It pays to be paranoid like this since if you want to detect bugs early and swiftly.

Now the strategy for profiling an entire DLL is to:

  • Instrument the DLL. This means to inject performance related commands into the code. Don’t worry it’s perfectly safe.
    • Turn on performance profiling via a global command.
      • Run your unit tests. Here is where the real work gets done.
    • Turn off performance profiling via a global command. (A results file gets saved somewhere).
  • Un-Instrument the DLL. This means restoring it to it’s original state. (i.e. Don’t ship a DLL with performance profiling enabled).

Instrument the Binaries

I instrument my DLL’s using the following batch script called: Instrument_ON.bat

  1. @echo off
  3. @echo Instrumenting Binary
  4. set VS90TEAMTOOLS="%VS90COMNTOOLS%..\..\Team Tools\Performance Tools\"
  6. %VS90TEAMTOOLS%\VSInstr.exe ..\ManagedAPI\Win32\Debug\UnderstandWrapper.ManagedAPI.dll
  7. %VS90TEAMTOOLS%\VSInstr.exe ..\UnitTest\bin\x86\Debug\UnitTest.dll
  8. pause
  9. @echo on

The results of instrumenting it looks like this:

Instrumenting Binary
Microsoft (R) VSInstr Post-Link Instrumentation 9.0.30729 x86
Copyright (C) Microsoft Corp. All rights reserved.

File to Process:
   F:CodePlexUnderstandAPIManagedManagedAPIWin32DebugUnderstandWrapper.ManagedAPI.dll –> F:CodePlexUnderstandAPIManagedManagedAPIWin32De
Original file backed up to F:CodePlexUnderstandAPIManagedManagedAPIWin32DebugUnderstandWrapper.ManagedAPI.dll.orig

Successfully instrumented file F:CodePlexUnderstandAPIManagedManagedAPIWin32DebugUnderstandWrapper.ManagedAPI.dll.
Warning VSP2013 : Instrumenting this image requires it to run as a 32-bit process.  The CLR header flags have been updated to reflect this.
Microsoft (R) VSInstr Post-Link Instrumentation 9.0.30729 x86
Copyright (C) Microsoft Corp. All rights reserved.

File to Process:
   F:CodePlexUnderstandAPIManagedUnitTestbinx86DebugUnitTest.dll –> F:CodePlexUnderstandAPIManagedUnitTestbinx86DebugUnitTest.dll
Original file backed up to F:CodePlexUnderstandAPIManagedUnitTestbinx86DebugUnitTest.dll.orig

Successfully instrumented file F:CodePlexUnderstandAPIManagedUnitTestbinx86DebugUnitTest.dll.
Press any key to continue . . .

Turn on Monitor

I then turn on performance profiling using the following batch script called: Performance_ON.bat

  1. @echo off
  3. @echo Turning ON performance coverage session recorder
  4. set VS90TEAMTOOLS="%VS90COMNTOOLS%..\..\Team Tools\Performance Tools"
  5. %VS90TEAMTOOLS%\VsPerfCmd /start:trace /output:ManagedAPI.vsp
  6. pause
  7. @echo on

The results of this batch scripts looks like this:

Turning ON performance coverage session recorder
Microsoft (R) VSPerf Command Version 9.0.30729 x86
Copyright (C) Microsoft Corp. All rights reserved.

Press any key to continue . . .

The results of this script is it starts another process that will monitor any application that happens to be instrumented with performance profiling, or code coverage profiling. In our case it started a process called VsPerfMon.exe:


Run Unit Tests

I then run all the unit tests in my DLL using another batch script. Now I have two build configurations (debug and release) so I have two batch scripts to run those: Run_Tests_Debug.bat and Run_Tests_Release.bat. Here is one of them:

  1. @echo off
  2. color 16
  3. @echo Running Unit Tests
  4. call "C:\Program Files (x86)\Microsoft Visual Studio 9.0\Team Tools\Performance Tools\VsPerfCLREnv" /traceon
  5. call "C:\Program Files (x86)\Microsoft Visual Studio 9.0\VC\vcvarsall.bat";
  7. mstest /testcontainer:%CD%\UnitTest\bin\x86\Debug\UnitTest.dll > results.txt
  9. pause
  10. @echo on

Notice there the actual call to mstest.exe is what runs the unit tests. Notice that I piped the results of running the actual unit tests into a text file (i.e. results.txt). I did this because it gives me a more permanent record of how my unit tests did.

The mstest.exe file resides on my computer at:

"C:Program Files (x86)Microsoft Visual Studio 9.0Common7IDEMSTest.exe"

The output, to the console window, of this script on my looks like the following:

Running Unit Tests
Enabling VSPerf Trace Profiling of managed applications (excluding allocation profiling).

Current Profiling Environment variables are:
Setting environment for using Microsoft Visual Studio 2008 x86 tools.
Press any key to continue . . .

Noticed I redirected the standard output (standard out) to a text file. The results.txt file looks like this:

Microsoft (R) Test Execution Command Line Tool Version 9.0.30729.1
Copyright (c) Microsoft Corporation. All rights reserved.
Loading F:CodePlexUnderstandAPIManagedUnitTestbinx86DebugUnitTest.dll…
Starting execution…

Results               Top Level Tests
——-               —————
Passed                UnitTest.DatabaseTest.DatabaseTest_GetAllEntities
Passed                UnitTest.DatabaseTest.DatabaseTest_GetFileEntities
Passed                UnitTest.DatabaseTest.DatabaseTest_LookupEntity
Passed                UnitTest.DatabaseTest.DatabaseTest_LookupEntitybyReference
Passed                UnitTest.DatabaseTest.DatabaseTest_LookupEntityUnique
Passed                UnitTest.DatabaseTest.DatabaseTest_LookupFile
Passed                UnitTest.DatabaseTest.DatabaseTest_Misc
Passed                UnitTest.DatabaseTest.DatabaseTest_OpenClose
Passed                UnitTest.Derived.ClassTypeTest.TestClassNests
Passed                UnitTest.Derived.ClassTypeTest.TestClassType
Passed                UnitTest.Derived.ClassTypeTest.TestClassTypeDerivedFrom
Passed                UnitTest.Derived.ClassTypeTest.TestClassTypeEnums
Passed                UnitTest.Derived.ClassTypeTest.TestClassTypeFields
Passed                UnitTest.Derived.ClassTypeTest.TestClassTypeInheritance
Passed                UnitTest.Derived.ClassTypeTest.TestClassTypeTemplates
Passed                UnitTest.Derived.ClassTypeTest.TestClassTypeUnions
Passed                UnitTest.Derived.ClassTypeTest.TestGetDefinedMethods
Passed                UnitTest.Derived.ClassTypeTest.TestGetMethods
Passed                UnitTest.Derived.EnumTypeTest.EnumTest_Enumerators
Passed                UnitTest.Derived.EnumTypeTest.EnumTest_Type
Passed                UnitTest.Derived.FileEntityTest.TestFileEntity
Passed                UnitTest.Derived.FileEntityTest.TestFileEntity_base_h
Passed                UnitTest.Derived.FileEntityTest.TestFileEntity_classes_h
Passed                UnitTest.Derived.FileEntityTest.TestFileEntityClassTypes
Passed                UnitTest.Derived.MethodTypeTest.MethodTest_Constructor
Passed                UnitTest.Derived.MethodTypeTest.MethodTest_Inline
Passed                UnitTest.Derived.MethodTypeTest.MethodTest_Inline_B
Passed                UnitTest.Derived.MethodTypeTest.MethodTest_LexerStuff
Passed                UnitTest.Derived.MethodTypeTest.MethodTest_Member_A
Passed                UnitTest.Derived.MethodTypeTest.MethodTest_Member_B
Passed                UnitTest.Derived.MethodTypeTest.MethodTest_Member_C
Passed                UnitTest.Derived.MethodTypeTest.MethodTest_Member_D
Passed                UnitTest.Derived.MethodTypeTest.MethodTest_Member_E
Passed                UnitTest.Derived.MethodTypeTest.MethodTest_Member_F
Passed                UnitTest.Derived.MethodTypeTest.MethodTest_MemberBlank
Passed                UnitTest.Derived.MethodTypeTest.MethodTest_Overrides
Passed                UnitTest.Derived.MethodTypeTest.MethodTest_Pure
Passed                UnitTest.EntityTest.EntityTest_Basic
Passed                UnitTest.EntityTest.EntityTest_Comments
Passed                UnitTest.EntityTest.EntityTest_Comments_Enums
Passed                UnitTest.EntityTest.EntityTest_Comments_FunctionDeclarations
Passed                UnitTest.EntityTest.EntityTest_Comments_FunctionDefinitions
Passed                UnitTest.EntityTest.EntityTest_Comments_Typedefs
Passed                UnitTest.EntityTest.EntityTest_FileReference
Passed                UnitTest.EntityTest.EntityTest_LineNumbers
Passed                UnitTest.EntityTest.EntityTest_LineNumbers_FunctionDeclarations
Passed                UnitTest.EntityTest.EntityTest_LineNumbers_FunctionDefinitions
Passed                UnitTest.EntityTest.EntityTest_LineNumbers_UnresolvedMethods
Passed                UnitTest.EntityTest.EntityTest_Refs
Passed                UnitTest.EntityTest.EntityTest_Types
Passed                UnitTest.KindTest.KindTest_Basic
Passed                UnitTest.LexerTest.Lexer_Test
Passed                UnitTest.LexerTest.Lexer_Test_GetLexeme
Passed                UnitTest.LexerTest.Lexer_Test_Next
Passed                UnitTest.LexerTest.Lexer_Test_Previous
Passed                UnitTest.LexerTest.Lexer_Test_Ref
Passed                UnitTest.ReferenceTest.ReferencesTest_Basic
Passed                UnitTest.ReferenceTest.ReferencesTest_Copying
58/58 test(s) Passed

Test Run Completed.
  Passed  58
  Total   58
Results file:      F:CodePlexUnderstandAPIManagedTestResultsChris Johnson_CHRISJOHNSON-PC 2010-02-17 23_38_54.trx
Run Configuration: Default Run Configuration

Feels good to see all the unit tests pass. But now I have to save out the results of the performance profiling. And to do this, I now have to turn off the VsPerfMon.exe process that is running, and was running when I ran my unit tests.

Turn off Monitor

I have a batch script that turns off monitoring and saves out a results file containing all the profiling goodness. Performance_OFF.bat

  1. @echo off
  3. @echo Turning off performance coverage session recorder
  4. set VS90TEAMTOOLS="%VS90COMNTOOLS%..\..\Team Tools\Performance Tools"
  5. %VS90TEAMTOOLS%\VSPerfCmd /shutdown
  7. pause
  8. @echo on

The results of this batch script looks like this:

Turning off performance coverage session recorder
Microsoft (R) VSPerf Command Version 9.0.30729 x86
Copyright (C) Microsoft Corp. All rights reserved.

Shutting down the Profile Monitor
Press any key to continue . . .

Now a new file is saved out to my computer:


Notice the name: ManagedAPI.vsp. This is the same name I passed in when I turned on the Performance Monitor. Remember this?

from: Performance_ON.bat

VsPerfCmd /start:trace /output:ManagedAPI.vsp

Now at this point, you can do two things:

  1. Examine your performance results. This is done by double clicking the ManagedAPI.vsp file. This will just launch visual studio, and display the results of your tests:
  2. Or Uninstrument your DLL’s. It’s never a good idea to ship DLL’s with instrumentation in them. 🙂

Un-Instrument the Binaries

I have a script that does this for me: Instrument_OFF.bat

  1. @echo off
  3. @echo Removing Instrumented Files
  5. pushd ..\ManagedAPI\Win32\Debug
  6. if exist UnderstandWrapper.ManagedAPI.instr.pdb (
  7.     del UnderstandWrapper.ManagedAPI.instr.pdb
  8.     del UnderstandWrapper.ManagedAPI.dll
  9.     rename UnderstandWrapper.ManagedAPI.dll.orig UnderstandWrapper.ManagedAPI.dll
  10. )
  11. popd
  13. pushd ..\UnitTest\bin\x86\Debug
  14. if exist UnitTest.instr.pdb (
  15.     del UnitTest.instr.pdb
  16.     del UnitTest.dll
  17.     rename UnitTest.dll.orig UnitTest.dll
  18. )
  19. popd
  21. pause
  22. @echo on

When I run this, I get the following results in the command window:

Removing Instrumented Files
Press any key to continue . . .

However, sometimes I do this only after I reviewed my performance results. Since the performance results display in visual studio may be dependent on the instrumented binaries to properly display its data.

View Results

Now that you have your .vsp file it is time to open it. The file ManagedAPI.vsp shows the following in visual studio:


From there you can analyze the results and find your performance bottlenecks.

4 thoughts on “How to Instrument a Unit Test DLL for performance profiling in VS 2008

  1. Well, your process does work. I had to make one adjustment of copying the instrumented codeUnderTest dll from bindebug to objdebug. The instrumented test code was in objdebug and the instrumented code under test was in bindebug.

    I made batch files for all as you suggested.
    But oh my, that is tedious. If I develop a more portable form of all this, I will share it. I will be glad if Microsoft automated that for us. It looks as if Chris Schmich will at least propose it.

    I am impressed with the depth of knowledge you displayed to figure all that out. Nice work and thanks.


  2. Oh, I figured out why I had to make the adjustment above. I had instrumented the bindebug version of the code under test and the objdebug version of the test code. And I was running MSTEST with the wrong one.

    Anyway, I have it all working now. I wanted to make it more reusable but I keep getting into trouble with the way VIsual Studio passes in arguments. So I’m just hard-coding the paths. Once it is setup, it’s not so bad.

    Thanks again.


  3. Chris Johnson

    I could probably make the batch scripts more portable by using the VS90COMNTOOLS environment variable to extract the location of my visual studio directory. and hence have less reliance on hard-coded paths.
    I could probably even combine the first two batch scripts into one, and the last two batch scripts into one as well. That would certainly be simpler of course.


  4. Chris Johnson

    I have updated the outer batch scripts so they have less reliance on hard coded paths. They now rely on the environment variable: VS90COMNTOOLS that is set when visual studio in installed.


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