topic Re:Vtune driver vtss.sys breaks CPU Sampling with ETW in Analyzers

Vtune driver vtss.sys breaks CPU Sampling with ETW

Alois — Mon, 27 Jun 2022 06:26:00 GMT

Is this a known issue that VTune breaks CPU sample collection data once it becomes active?

\SystemRoot\system32\drivers\vtss.sys

See attached Screenshot of WPA and ETWAnalyzer which shows that the last sample was provided by driver vtss.sys which correlates with 0 CPU samples afterwards.

Is there an easy way to disable this driver without uninstalling vtune? Is this a known issue?

I have tried to change the key ImagePath in Computer\HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\vtss

but that did not prevent the driver from loading.

ETWAnalyzer is a tool to query ETW data which has some pretty powerful analysis capabilities.

The query sorts all methods shown in CPU sampling/CSwitch data by their first occurrence in profiling data for the system process. -fld s shows first last duration where additionally the first time in s since trace start is shown.

Re:Vtune driver vtss.sys breaks CPU Sampling with ETW

JananiC_Intel — Wed, 29 Jun 2022 06:19:07 GMT

Hi,

Thanks for posting in Intel Forum.

In order to try from our end, we need a sample reproducer. Could you share the reproducer with us?

For your information, we have four vtune drivers like socperf3, sep5,socwatch and vtsspp. To disable the vtune driver you can go to "/opt/intel/oneapi/vtune/2022.3.0/sepdk/src" path where you can find all four driver directories and give "./rmmod-" to remove the driver. For example, if you want remove socperf3 do the following.

cd /opt/intel/oneapi/vtune/2022.3.0/sepdk/src/socperf/src

./rmmod-socperf

Hope this helps.

Regards,

Janani Chandran

Re: Re:Vtune driver vtss.sys breaks CPU Sampling with ETW

Alois — Wed, 29 Jun 2022 17:53:08 GMT

I think you are giving hints how to remove the drivers on Linux. ETW (Event Tracing for Windows) is a Windows only thing.

I would need some hints how to prevent loading the driver on Windows.

To reproduce

1. Install VTune on Windows

2. Enable a boot recording with WPR (an older version is part of Windows) on an elevated cmd shell

wpr -addboot CPU -filemode

3. Reboot

4. Login again and execute on an elevated cmd shell

wpr -boottrace -stopboot c:\temp\VTuneBreaksETWProfiling.etl -skippdbgen

5. Open generated ETL file in Windows Performance Analyzer which comes e.g. with Windows 11 SDK as part of the Windows Performance Toolkit. Check https://developer.microsoft.com/en-us/windows/downloads/windows-sdk/ to either use the installer and select in the installer only Windows Performance Toolkit.

If you get an error while stopping: Cannot change thread mode after it has been set you need to use the newer wpr from the Windows 11 SDK. If you type where wpr you can see which one comes first and change the order in the PATH environment to ensure that the newer one is picked first, or you fully qualify the exe: C:\Program Files (x86)\Windows Kits\10\Windows Performance Toolkit\wpr.exe

Re:Vtune driver vtss.sys breaks CPU Sampling with ETW

JananiC_Intel — Thu, 04 Aug 2022 06:09:29 GMT

Sorry for keeping you waiting.

We could see this vtss.sys file in “C:\Program Files (x86)\Intel\oneAPI\vtune\2022.2.0\bin64\sepdrv” path.

When we run “amplxe-sepreg.exe -i” command ,after removing or moving vtss.sys from that particular path vtsspp is not loaded. Also after this when we run self-checker we found vtsspp driver disabled.

Could you try this above workaround and let us know?

Regards,

Janani Chandran

Re:Vtune driver vtss.sys breaks CPU Sampling with ETW

JananiC_Intel — Thu, 11 Aug 2022 09:20:58 GMT

Hi,

Is your issue resolved? Do you have any update?

Regards,

Janani Chandran

Re: Re:Vtune driver vtss.sys breaks CPU Sampling with ETW

Alois — Fri, 12 Aug 2022 08:34:59 GMT

I have renamed the driver in the Windows folder

C:\Windows\System32\drivers>move vtss.sys vtss.sys_orig

That did work. I did not dare to do this initially since I did not want to get a blue screen when windows no longer boots due to a missing driver. ETW Boot Trace Profiling is then working with CPU sampling.

To get the driver back to work again I can use your command:

"C:\Program Files (x86)\Intel\oneAPI\vtune\2022.2.0\bin64\amplxe-sepreg.exe" -i

Warning, socperf3 driver is already installed and will be re-used... skipping
Installing and starting sepdrv5...
OK
Installing and starting sepdal...
OK
Installing and starting VTSS++ driver...OK

Then I get the driver back. That is a workable solution to get both profilers happy, also during boot trace. Thanks!

Re:Vtune driver vtss.sys breaks CPU Sampling with ETW

JananiC_Intel — Fri, 12 Aug 2022 09:27:07 GMT

Hi,

Glad to know that your issue is resolved. Thanks for sharing the solution with us. If you need any additional information, please post a new question as this thread will no longer be monitored by Intel.

Regards,

Janani Chandran