Strange DPC Latency issues, cannot use Latencymon due to access violation.

[Serafish]

Hello! I've recently been having some strange DPC latency issues that greatly hinder my ability to use my computer. I've scoured the forums and found the tutorial here:

https://www.sysnative.com/forums/wi...ues-with-wpa-windows-windows-vista-7-8-a.html

I use a 32-bit vista system, so I downloaded Latencymon 6.0 Free in order to identify what's causing the DPC issues, but to my dismay, I get an "Access violation at address 005FA1E6 in module "latmon.exe. Read of address 0000039c".


So far, based on my observations:

- Moving my linksys wmp600n card from one PCI slot to another does not work

- updating the drivers do not work

- updating the chipset did not do anything to fix it.

- REMOVING the card stops the all DPC latency issues, however, I the need internet.

- Adding in a new wireless adapter card still causes issues.


I've been stumped on this one, all thanks to that Latencymon access violation that prevents me from seeing the problem, and I really need this computer to work again. Please, help me solve this!

 

[Trouble]

Hello and welcome to the forum.
Just as a test.....
Try dropping your wireless router from "N" to "B / G" and see if that impacts the latency issue.
If so....
See if there is a firmware update for your particular Manufacturer, Model Number, Revision Number.

 

[TomasD]

Dear,

To properly troubleshoot issues with high/frequent DPCs/IRPs, we require a XPERF trace. Please follow these steps to generate one:

1. Download Windows Software Development Kit (SDK) for Windows and run the setup.
2. Select Windows Performance Toolkit feature (all the others can be unchecked) and proceed with the download/installation.
3. Once the installation finishes, open an elevated Command Prompt by right-clicking on CMD.EXE shortcut in your start menu and selecting Run As Administrator from the context menu.
4. Type the following command, which will start tracing, in the Command Prompt window you just opened:
   

   xperf -on PROC_THREAD+LOADER+PROFILE+INTERRUPT+DPC+DRIVERS+POWER+IDLE_STATES -stackwalk Profile -BufferSize 1024 -MinBuffers 256 -MaxBuffers 256 -MaxFile 256 -FileMode Circular

   If you see a yellow warning "xperf: warning: This system is not fully configured for x64 stack tracing" after running the above command, please complete these extra steps (otherwise, proceed to the step #5):
   
   Read More:

   1. Run the following command which will stop the tracing:
      

      xperf -stop

   2. Run the following command to enable stack tracing (by disabling Paging Executive):
      

      REG ADD "HKLM\System\CurrentControlSet\Control\Session Manager\Memory Management" -v DisablePagingExecutive -d 0x1 -t REG_DWORD -f

   3. Reboot the computer
   4. Once computer reboots, proceed from the step #3
   If you see a red error "xperf: error: NT Kernel Logger: A device attached to the system is not functioning. (0x1f)" after running the above command, please complete these extra steps (otherwise, proceed to the step #5):
   
   Read More:

   
   

   1. Run the following command to disable Driver Verifier, which causes the above error:
      

      verifier /reset

   2. Reboot the computer
   3. Once computer reboots, proceed from the step #3
5. Perform some activities with your computer for few minutes, making sure the issues you reported are reproduced.
6. Run the following command, which will stop the tracing, in the command prompt window you already have opened:
   

   xperf -stop -d C:\CPU.etl

7. Compress file C:\CPU.etl
8. Upload the compressed file to a file sharing service (e.g. OneDrive or DropBox).
9. Share the download link here.

Thank you.

 

[Serafish]

Hello and welcome to the forum.
Just as a test.....
Try dropping your wireless router from "N" to "B / G" and see if that impacts the latency issue.
If so....
See if there is a firmware update for your particular Manufacturer, Model Number, Revision Number.

Tried that, DPC latency still present.

Also using the latest driver, rolling back or updating to the latest one still doesn't work.



Also Tomas, the cmd prompt can't recognize xperf for some strange reason, does it only work in 64 bit systems?

 

[TomasD]

Also Tomas, the cmd prompt can't recognize xperf for some strange reason, does it only work in 64 bit systems?

If it doesn't recognize XPERF command, it likely means that you either had CMD already launched (you need to re-open it after the installation) or you haven't installed it correctly (are you sure you selected Windows Performance Toolkit and the installation was successful?).

 

[Serafish]

Also Tomas, the cmd prompt can't recognize xperf for some strange reason, does it only work in 64 bit systems?

If it doesn't recognize XPERF command, it likely means that you either had CMD already launched (you need to re-open it after the installation) or you haven't installed it correctly (are you sure you selected Windows Performance Toolkit and the installation was successful?).

Yes, I see it in C:\Program Files\Windows Kits\8.1\Windows Performance Toolkit

However, every time I run an XPERF command in the cmd line ( as administrator) I get the "Xperf is not a valid win32 application" error.

 

[TomasD]

Could you try running this setup "C:\Program Files\Windows Kits\8.1\Windows Performance Toolkit\Redistributables\WPTx86-x86_en-us.msi"?

 

[Serafish]

Could you try running this setup "C:\Program Files\Windows Kits\8.1\Windows Performance Toolkit\Redistributables\WPTx86-x86_en-us.msi"?

The redistributable folder and that file are not in the performance kit folder! The only folders in there are the catalog and gpuview. Is there another way to get wptx86-x86 en-us.msi?

 

[TomasD]

The redistributable folder and that file are not in the performance kit folder! The only folders in there are the catalog and gpuview. Is there another way to get wptx86-x86 en-us.msi?

You can run the SDK setup again and select Download instead. Select the location and check Windows Performance Toolkit. Once it finishes, you should find the setup at the location you specified.

 

[Serafish]

The redistributable folder and that file are not in the performance kit folder! The only folders in there are the catalog and gpuview. Is there another way to get wptx86-x86 en-us.msi?

You can run the SDK setup again and select Download instead. Select the location and check Windows Performance Toolkit. Once it finishes, you should find the setup at the location you specified.

Aha! Now the folder shows up, clicked on wptx86-x86 en-us.msi, the installation was quite fast. What do I do next?

 

[TomasD]

The redistributable folder and that file are not in the performance kit folder! The only folders in there are the catalog and gpuview. Is there another way to get wptx86-x86 en-us.msi?

You can run the SDK setup again and select Download instead. Select the location and check Windows Performance Toolkit. Once it finishes, you should find the setup at the location you specified.

Aha! Now the folder shows up, clicked on wptx86-x86 en-us.msi, the installation was quite fast. What do I do next?

Have you tried running XPERF again? If it's still fails, try removing everything you installed before, deleting C:\Program Files\Windows Kits folder and then running wptx86-x86 en-us.msi setup again.

 

[Serafish]

The redistributable folder and that file are not in the performance kit folder! The only folders in there are the catalog and gpuview. Is there another way to get wptx86-x86 en-us.msi?

You can run the SDK setup again and select Download instead. Select the location and check Windows Performance Toolkit. Once it finishes, you should find the setup at the location you specified.

Aha! Now the folder shows up, clicked on wptx86-x86 en-us.msi, the installation was quite fast. What do I do next?

Have you tried running XPERF again? If it's still fails, try removing everything you installed before, deleting C:\Program Files\Windows Kits folder and then running wptx86-x86 en-us.msi setup again.

Ran XPERF again after reinstalling the performance Tools, I still get the "Not a valid win32 application" error along with access denied on the cmd prompt.

 

[TomasD]

That's strange. Could you please provide some Event Logs to better understand the problem (as you're having issues with LatencyMon and XPERF, I would like to confirm if the issue isn't somewhere else). Please perform the following steps:

1. Open an elevated Command Prompt by right-clicking on CMD.EXE shortcut in your start menu and selecting Run As Administrator from the context menu.
2. Type the following commands:
   

   WEVTUTIL EPL System %USERPROFILE%\Desktop\System.evtx
   WEVTUTIL EPL Application %USERPROFILE%\Desktop\Application.evtx

3. Compress all the exported Event Log files (.evtx) from your desktop to a single archive and attach it here.

Thank you.

 

[Serafish]

That's strange. Could you please provide some Event Logs to better understand the problem (as you're having issues with LatencyMon and XPERF, I would like to confirm if the issue isn't somewhere else). Please perform the following steps:

1. Open an elevated Command Prompt by right-clicking on CMD.EXE shortcut in your start menu and selecting Run As Administrator from the context menu.
2. Type the following commands:
   

   WEVTUTIL EPL System %USERPROFILE%\Desktop\System.evtx
   WEVTUTIL EPL Application %USERPROFILE%\Desktop\Application.evtx

3. Compress all the exported Event Log files (.evtx) from your desktop to a single archive and attach it here.

Thank you.

I got Latencymon to work! I just downloaded version 5.0 instead of 6 and it works correctly. The following screenshot in gyazo is my latencymon chart

http://i.gyazo.com/a4bc95c38d0b628d7bb78c040c186675.png

 

[Serafish]

View attachment Event logs.rar

Also, here are the event logs

 

[TomasD]

Thanks for the logs. There doesn't seem to be any serious problems indicated in them.

The only thing I could suggest base on the LatencyMon screenshot is to upgrade your Nvidia drivers to the most recent version. To be able to provide more suggestions, we would still need a XPERF trace.