How to Diagnose and Fix High DPC Latency Issues with WPA (Windows Vista/7/8)

This tutorial will show you how to identify drivers causing high Deferred Procedure Call (DPC) latencies. Spikes of high DPC latency can cause a computer to slow to a crawl for a few seconds before speeding up again in super-speed to catch up, then repeating a number of seconds later. During the few seconds of slowness (high latency spike), you may notice jerky and erratic mouse movement, poor quality, stuttering, audio, and pausing and skipping in real time video playback. If these symptoms sound familiar, read on.

The technique outlined below will work on Windows 7 and Windows 8. It will not work on Windows XP, but an alternative for Step II has been briefly outlined at the bottom of this tutorial for Windows Vista.

In addition, this technique is fairly technically advanced. Although it should be perfectly possible for anyone to complete provided you follow carefully the instructions given, if you require further clarification of any particular steps, or run into any sort of difficulties, please do not hesitate to ask us for help.


Step I (optional): Making a Quick Diagnosis:
[This part is not yet possible on Windows 8 computers. If you are using Windows 8, please skip ahead to Step II]

This step will allow you to quickly and easily determine whether or not high DPC latencies are indeed a problem on your computer. It is not necessary to perform this step, since it will not show you the cause of any DPC latency spikes it does find. Step II will be used to determine the cause any of such problems, and so you may wish to skip ahead to Step II now.

1. Download and run DPC Latency Checker from this website: DPC Latency Checker

2. Allow it to run until you have experienced a period of lagging and computer slowness. It is important to allow the program to run through such a time period in order to make a proper diagnosis. Having it running only whilst the computer is performing normally is not nearly as effective.

3. Analyze the graph for a large spike into the reds. A healthy graph will remain in the green section, and will look similar to this:
1.PNG

A graph containing spikes into the red (indicative of a DPC latency problem) will look similar to this:
2.png
Now identify whether or not you have a DPC Latency problem using the graphs given above as a reference. If you do, continue on to Step II to identify the cause of this problem.



Step II (if necessary): Identifying the Cause:
[This technique is not possible on Windows Vista computers. If you are using Windows Vista, please skip ahead to the end of this step for a briefly outlined alternative.]
This step will use the Microsoft Windows Performance Analyzer from the Windows Assessment and Deployment Kit (ADK) to identify the cause of any DPC latency spikes.

1. Download the ADK from this website: Download Windows Assessment and Deployment Kit (ADK) for Windows® 8.1 from Official Microsoft Download Centre
Ignore the reference to Windows 8.1. This download applies to both Windows 7 and Windows 8.

2. Run ADKSetup.exe and allow it to initialize past the splash screen.
[The following screenshots may be expanded by clicking on them if registered]

Click Next:
3.PNG


Click Next again (you may opt in to CEIP if you so wish - it is not necessary, but you may wish to do so):
4.PNG


Click Accept:
5.PNG


Alter the checkmarks to be next to the following box only:
Windows Performance Toolkit

and click Install.
10.PNG


Allow the install to complete:
11.PNG


and finally click Close:
9.PNG



Part 2:

[Windows 7] Click on the Start Orb, search for cmd, and press Enter.
[Windows 8] Swipe up or right click on the Start Screen, select All Apps, swipe or scroll to the right, and under the Windows System section, open Command Prompt.

Now, in Command Prompt:

Type out the following line and press Enter:
xperf -on DiagEasy

Nothing much will appear to happen, but xperf is now logging. Wait until the computer has gone through a period of stuttering slowness, and then type out the next line and press Enter (this line may take several seconds to process):
xperf -d %userprofile%\Desktop\trace.etl

Finally type this line and press Enter:
xperf %userprofile%\Desktop\trace.etl

If you get prompted the following message, select Yes:
1.PNG



A new window will now open, and after initializing, will containing several graphs.

Scroll down to the graph titled DPC CPU usage, right click on it, and select Summary Table. The example graph show below comes from a healthy computer, yours is likely to show much larger spikes and a smaller scale on the % usage axis.
2.PNG



A final new window will open containing a list of drivers. This list is already correctly sorted (by the Actual Duration column). The driver on the very top of the list is therefore likely to be the cause of your problem. Note down its name from the leftmost column.
3.PNG



You may now close both Windows Performance Analyzer windows and go back to the Command Prompt.

Type the following line final line and press Enter:
del %userprofile%\Desktop\trace.etl

Now close the Command Prompt window.


Part 3:

Now you need to fix the problem. With the driver name in hand, first try to identify where it comes from. Our Driver Reference Table (located here: Driver Reference Table) will help you with this task. It is a large database of many common drivers, and it is likely that the driver you are searching for is there. If you are, however, unable to identify the driver there, please do not hesitate to ask us for help.

Once you have identified the driver, you need to update it from the manufacturer's website. The Driver Reference Table should point you to such a website for the drivers that are contained within it.

Just download and install the latest version of the driver, and hopefully your DPC related problems will be resolved.


However, if they are not resolved, you continue to have problems after updating the driver, or you continue to experience other problems, please do not hesitate to ask us for assistance, providing as much detail as is possible. You will be required to register with this forum before you are able to create a new thread (you can register here: Register at Sysnative Forums), but this process is quick and completely free.



Alternative Step II for Windows Vista

As an alternative to Step II for Windows Vista computers, you may use a program called LatencyMon which can be downloaded here: Resplendence Software - Free Downloads

Once installed, start LatencyMon from the Start Orb > All Programs > LatencyMon.

In the top left hand corner of the window which opens, click on the green start button (highlighted in the image below). Then navigate to the Drivers tab, sort by the Total Execution (ms) column, and wait until the computer has gone through one of its periods of lagging or stuttering. Finally, read off and note down the driver at the top of the list, and continue with Part 3 of Step II.

4.PNG
 
Last edited:
I've been going through the tutorial, and things have been working out until the second command line entry. I enter that in, and the cmd box gives me this error:

Running cmd as Administrator:


xperf -on DiagEasy


Then after waiting a time for the chugging and slowdown, I entered:


xperf -d %userprofile%\Desktop\trace.etl


and receive:
xperf: error: -d: does not expect 2 argument(s).


And the cmd then describes a list of Trace Stop options.

Is there an alternative command I can use?
 
xperf -d %userprofile%\Desktop\trace.etl

and receive:
xperf: error: -d: does not expect 2 argument(s).

Does your computer username contain a space or other non-alpha, non-numeric character?

If so, try the command with quotes:

Code:
xperf -d "%userprofile%\Desktop\trace.etl"

Regrds. . .

jcgriff2
 
Does your computer username contain a space or other non-alpha, non-numeric character?

If so, try the command with quotes:

Code:
xperf -d "%userprofile%\Desktop\trace.etl"

Regrds. . .

jcgriff2
That was it. Thanks!
 
Re: I need Help when I get to part two.

[ I have gotten as far as part two and then when I type in the "xperf-on DiagEasy" my computer says ""Xperf" is not recognized as an internal or external command, operable program or batch file" Please help me I just got this laptop for Christmas and it already has a crackle in the speaker]
 
Hi, I'm having problems getting out of the starting gate...have downloaded & installed ADK with the Performance Toolkit, but when I enter "xperf-on DiagEasy" at the command prompt I receive only 'xperf-on' is not recognized as an internal or external command, operable program or batch file. I've tried running the command both simply at "cmd.exe", and also right clicking cmd.exe > Run as Administrator. Thanks for any help...
 

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Excellent guide, but I am having a command error with this command xperf %userprofile%\Desktop\trace.etl.

I even tried it from the Desktop subdirectory.
C:\Users\xxxxxx\Desktop>xperf trace.etl
xperf: error: trace.etl: The parameter is incorrect. (0x80070057).

Microsoft (R) Windows (R) Performance Analyzer Version 6.3.9600
Performance Analyzer Command Line
I loaded the etl file manually in Windows Performance Analyzer, but none of the views I saw conformed with the instructions, so I cannot find the right screens to follow along. My Windows Performance Analyzer version is version 6.3.9600.16384 winblue rtm 130821-1623
Thank you for any assistance you can offer.

Instant Update: Okay, just found at technet that xperf is no longer valid for that function. It is changed to "wpa" on the command line. However, I still need some guidance on where to find the correct graphs as they seem to have changed things around a bit.

https://social.technet.microsoft.co...-the-parameter-is-incorrect?forum=w8itproperf
 
Hi, thanks for the tutorial - the steps are well explained maybe except the fact that you have to wait couple of minutes to generate log files which is quiet big.

It my case it shows the NDIS.SYS is the reason - how can I fix it ?
I run also Latencymon - showing that TCPIP.SYS is a problem.

I believe all this is related to network.
Device Manager shows that all my drivers are correct and I installed newest one from Dell website but it does not help.
I also updated nvidia drivers, clean computer with cccleaner, checked for virus, run Malwarebytes , disconnected windows security essential - nothing helps

My cpu goes sometimes up to 100% when watching online videos ( in any browser, html5 player or flash ) most of the time , but it can also happen when I open too many tabs even without video.
It usually goes away after a minute or two , or when I close browser.
Recently it happened when playing music in vlc.

This thing is really driving me nuts - never had such a problem.
I have 4 years old dell precision m4500 , i7, 8gb ram, nvidia quadro card. The problem is new - I experience it since one month and don't remember any major changes which could cause it.

Please help
 
I do hope I am using this forum right, but I am trying this diagnosis and get stuck on a certain point.
When I use the cmd(in admin mode)
xperf - d gebruiker\desktop\trace.etl

I get the following RED message:
xperf: error: NT Kernel Logger: The instance name passed was not recognized as valid by a WMI data provider (0x1069)

Can anybody help me?
 
I did try it and I get a different error:
xperf: Error: Merge ETL: system cant find given path (0x3) (translated from Dutch)
 
Uh?
Try the entire path:
Code:
xperf -d "c:\users\your-user-name\Desktop\trace.etl"

(obviously, you should put the real username of your user account, instead of your-user-name in that code)
 
Yay! I tried it and it worked, Thank you!
After that I had to use WPA to get the analysis. I have the chart and the table. It shows one huge spike, which corresponds to my problem.
Only it doesnt show the names of the modules. I made a screenshot:
DPC duration by CPU.PNG
 
Yay! I tried it and it worked, Thank you!
After that I had to use WPA to get the analysis. I have the chart and the table. It shows one huge spike, which corresponds to my problem.
Only it doesnt show the names of the modules. I made a screenshot:
View attachment 10914

Please attach the ETL file to your other thread.
 
I get as far as putting xperf -on DiagEasy in command promt but i get the following error:

xperf: error: NT Kernel Logger: Access is denied. (0x5).

Any ideas?
 
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