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Application Crashes When Attempting Call Graph Profiling

Mon, 09 Nov 2009 13:53:38 -0800

Application Crashes When Attempting Call Graph Profiling

We have seen cases where a user's application will crash when the VTune analyzer launches the application for call graph profiling. Because of our binary instrumentation technology, and the injecting of code into a user application, sometimes various Microsoft* runtime libraries will cause the application to crash. Symptoms vary, but you may see the "unhandled exception" message and the "Just-In-Time Debugger" prompt from Visual Studio*.

Followed by the VTune analyzer "No results were generated for this run" message:

Reducing the instrumentation level of the Microsoft runtime libraries will often enable you to workaround this problem. Follow these steps to apply the workaround:

1) Right-click on the Activity in the Tuning Browser and select Modify Collectors...:

2) After the Configure Call Graph dialog appears, scroll the list of modules until you locate the msvcrnn[d].dll and msvcrt.dll modules. The nn represents the version of Visual Studio that you are using. In our example, Visual Studio 2005 was used and, therefore, nn = "80", as in 8.0. If you are using Visual Studio 2008, the module would be msvcr90.dll or msvcr90d.dll, where the 'd' representing the debug version of the DLL.

Note that color-coding is used in the module list. An explanation of the colors follows, and is available in the online help, as well.

Gray: Modules you added to the project from the Application/Module Profile Configuration dialog box, or from the Call Graph Configuration Wizard.
Blue: Modules added during call graph instrumentation as dependencies of the selected modules.
White: Modules you added via Add button, or added during run-time instrumentation.

3)      Click on the Instrumentation Level cell for the msvcr80.dll, for example, and select Minimal:

4)      Press Apply and then Instrument Now:

5)      Now OK out of all dialogs and re-run the activity.

In this example, simply reducing the instrumentation level of msvcr80.dll resolved the problem and results were successfully collected. The effect of reducing the instrumentation level on the runtime libraries is that no information regarding calls into those modules will be available in the call graph data. If this information is critical for your tuning activity, you can try to use the Custom Instrumentation (see Functions... button) to deselect functions until the call graph activity succeeds. Using a binary search technique, you would narrow down which function or functions fail when they are instrumented and select to not instrument them. Follow these steps to accomplish this task:

1)      Press Functions... for the module of concern. You will see a dialog box such as this:

2)      Now, using the scroll bar move to the middle of the list and select that line:

3)      Press Shift-Ctrl-End to select from this line to the bottom of the list. The horizontal scroll bar will move all the way to the right. Simply grab it and move it back to the left:

4)      Press the Uncheck button:

5)      Press OK and then Apply and Instrument Now:

6)      Notice that Instrumentation Level now shows Custom for the selected module.

7)      OK out of all dialogs and re-run the Activity.

If the application fails, again, modify the function selection so that the top half of the functions is selected and re-run the activity. In this way, you can narrow down which function(s) do not like to be instrumented (or "fail" when instrumented).

An alternative to the VTune analyzer's Call Graph feature is the Intel® Parallel Amplifier's Hotspot analysis. Parallel Amplifier uses a new technology to collect periodic samples, similar to "Clockticks" in the VTune analyzer, with complete call stacks, so that the call path to the hotspot is visible without instrumentation. If you have a valid license for the VTune analyzer that includes support through April 1, 2010, you can download, install, and use Parallel Amplifier without any additional cost.

Using the Microsoft* Symbol Server with the VTune(TM) Performance Analyzer

Mon, 03 Aug 2009 11:09:22 -0700

Starting with version 9.1 of the VTune analyzer, you can specify paths to the Microsoft* symbol server in a standard convention. For example, SRV*c:\websymbols*http://msdl.microsoft.com/download/symbols, in Configure > Options > Directories preference page for Symbol Files.

Use this feature to enable sampling data to be attributed to functions within system DLLs.

During downloading of the PDB files, you will see messages in the Output window similar to the following:

For more information regarding the Microsoft Symbol Server, please see http://www.microsoft.com/whdc/devtools/debugging/debugstart.mspx.

Some caveats:

This does not affect Call Graph instrumentation, that is, Call Graph will not instrument the functions within system DLLs even if you specify a path to the symbol server. This is by design. System DLLs are only instrumented at the Exports level.
Specifying a path for the Microsoft Symbol Server may slow down the following operations, especially with a slow Internet connection:
- Opening Sampling hot spot views
- Source View drill down
- Call Graph symbols resolution
- Static module viewer

Are Microsoft* Visual Studio* .NET* Symbols Supported?

Fri, 03 Oct 2008 16:09:39 -0700

Yes. The Intel® VTune™ Performance Analyzer does support Visual Studio* .NET* symbols for C, C++, C# and Visual Basic* languages. Please see the online help for information about generating symbols in the Visual Studio .NET environment. See the topic Microsoft* .NET* Compilers under Symbol and Debug Information.

Intel® VTune™ Performance Analyzer for Windows* - Time-based Sampling is Grayed Out

Fri, 19 Sep 2008 00:00:00 -0700

Symptom(s):
When using the sampling wizard to configure an activity for remote data collection or when configuring the sampling collector, the time-based sampling option is grayed out.

Solution:
Currently, only Event-based sampling (EBS) is supported by the remote agent for Linux*. Using EBS with the Clockticks event is usually equivalent to TBS. See the online help for information regarding Non-halt and Non-sleep Clockticks for certain Pentium® processors.

Operating System:

Linux*

Intel® VTune™ Performance Analyzer for Windows* - Turning on Debug Symbols for Borland* Delphi* Enterprise Version 6.0

Fri, 19 Sep 2008 00:00:00 -0700

To generate debug symbols for a Borland Delphi Enterprise Version 6.0 project:

Set the following in the Project/Options/Compiler/Debugging tab:
- Debug information
- Local symbols
- Reference info
- Assertions
Set the following in the Project/Options/Linker/EXE and DLL options tab:
- Include TD32 debug info
Set the following in the Project/Options/Linker/Map file tab:
- Off
Set the following in the Project/Options/Linker/Linker output tab:
- Generate DCUs

Note: Similar options should be applicable to Borland Delphi 7.0.

Operating System:

Windows* XP Professional, Windows Server* 2003, Windows Server* 2003 Standard Edition

Intel® VTune™ Performance Analyzer for Windows* - Known Issues on Windows Vista* and Windows* Longhorn Server Systems

Fri, 19 Sep 2008 00:00:00 -0700

Sampling driver called sepdrv.sys is not digitally signed. x64 editions of Windows Vista* operating system disable unsigned drivers by default so that it prevents sampling collection. In order to enable the driver, reboot the system, press F8 during the boot and select Disable Driver Signature Enforcement. This setting does not persist across boot sessions.
Installation may hang on Windows* Longhorn Server during CGExeCtrl.exe and CGExeCtrl_LINUX.exe registration. If it hangs, open Task Manager and end hanging processes CGExeCtrl.exe and CGExeCtrl_LINUX.exe and continue installation. Some call graph features may not work but the rest of features is not affected.

Operating System:

Windows Vista*

Intel® VTune™ Performance Analyzer 8.0 for Windows* - Dual-core Processors Supported by the Latest VTune™ Analyzer Releases

Fri, 19 Sep 2008 00:00:00 -0700

Usually VTune™ Performance Analyzer can be run on a system with any new Intel® processor and certain features such as call graph work in the same way they do on earlier processors. Other features such as sampling collection or disassembly view may give inadequate results. Please check product release notes for supported processors.