How to get the cause of high CPU usage by DPC / Interrupt

[MagicAndre1981]

do you have a 2nd mouse to test if this also occurs?

[3Seven]

do you have a 2nd mouse to test if this also occurs?

I've tested with 4 different mice that all have no acceleration whatsoever, same exact thing occurs: CM Spawn, Deathadder, Zowie AM, G400

Mouse Pads: QCK Heavy, Razer Goliathus, Artisan Hein, Desk itself

What I see in game: I get the same amount of negative acceleration with every mouse. The issue will occur even with extremely slow swipes, so i doubt it's that i'm hitting max tracking on my mice.

Moving my mice in a straight line across my pad will make my character in game look slightly to the ground as he pans to the side which lead me to believe it was an interrupt related problem.

I haven't been able to test a mouse over ps/2, but i have tested all my mice on a second PC where they all work flawlessly. There seems to be something wrong with motherboard itself as the issue persists even when re-installing windows and a BIOS update.

What I've tried so far:

1. Deleting / re-installing drivers

2. Re-installing the MarkC Fix

3. Closing all background programs while i game

4. Different video drivers

5. Making sure EPP is off and Windows is at 6/11 with 100% scaling

6. Re-installing my games

7. Unplugging any other device aside from my mouse while testing in game

8. Re-formatting to a completely fresh install

9. Trying different ports / disabling USB 3 and legacy in BIOS

10. BIOS flash

11. Disabling all power saving features / c steps

12. Stress testing my hardware (minus motherboard)

13. Checked hardware for any loose cables

14. Tried my SSD by itself and on every sata port

15. Installed Win 7 to HDD

16. Removing GPU and running on onboard video

17. Used one stick of RAM at a time

18. And lastly checking to see if my issue was DPC related by posting my info here

Everything minus the mouse movement in game works. I tried changing IRQ to see if it was a conflict issue, but Windows doesn't allow me to reassign them unless it says there's an issue.

I have no idea what else to do except to RMA the board, it worked fine for a short time then this issue came up out of nowhere.

Edited May 22, 2013 by 3Seven

[MagicAndre1981]

I have no idea what causes this.

[3Seven]

I have no idea what causes this.

Thanks for the help anyway.

[kilo85]

Hi Andre.

I have spent 3 days trying to figure out the cause of my latency spikes, I hope you can help me. I am getting 200-1900us spikes every 30 seconds and have tried everything to find out the cause

I have sent you the .etl, the only possible problem i see is with svchost, is this where my problem lies? If you can help ill be in your debt, these spikes are killing me!

Edited June 14, 2013 by kilo85

[MagicAndre1981]

the trace shows no spikes every 30s. the trace shows 1 small ndis.sys spike:

Total = 2307 for module ndis.sys
Elapsed Time, >      128 usecs AND <=      256 usecs,      0, or   0.00%
Elapsed Time, >      256 usecs AND <=      512 usecs,      0, or   0.00%
Elapsed Time, >      512 usecs AND <=     1024 usecs,      1, or   0.04%
Total,                                                  2307

First install the Sp1! RTM users don't get new updates! Now test if you still have the issues.

[kilo85]

the trace shows no spikes every 30s. the trace shows 1 small ndis.sys spike:

Total = 2307 for module ndis.sys
Elapsed Time, >      128 usecs AND <=      256 usecs,      0, or   0.00%
Elapsed Time, >      256 usecs AND <=      512 usecs,      0, or   0.00%
Elapsed Time, >      512 usecs AND <=     1024 usecs,      1, or   0.04%
Total,                                                  2307

First install the Sp1! RTM users don't get new updates! Now test if you still have the issues.

Hi Andre.

Thanks for the quick reply. its appreaciated!

Seems odd because i am getting spikes in both Latmon and DPClat. I have installed sp1 and run the tests again. I have PM'd you the results. I have included screenshots of DPC and LatMon. I have seen a slight improvment in my results after raising the virtual memory, if you still see no spikes do you think these spikes could be RAM related? I ask because when i remove one of my sticks of ram i get a black screen which seems odd.

Anyway hope you can offer me some advice because i have spent over 30 hours now trying to get to the bottom of this. Thanks

[MagicAndre1981]

I still can't see any DPC issues. The values are fine:

Total = 25890
Elapsed Time, >        0 usecs AND <=        1 usecs,   7141, or  27.58%
Elapsed Time, >        1 usecs AND <=        2 usecs,  12500, or  48.28%
Elapsed Time, >        2 usecs AND <=        4 usecs,   2160, or   8.34%
Elapsed Time, >        4 usecs AND <=        8 usecs,   2607, or  10.07%
Elapsed Time, >        8 usecs AND <=       16 usecs,    742, or   2.87%
Elapsed Time, >       16 usecs AND <=       32 usecs,    602, or   2.33%
Elapsed Time, >       32 usecs AND <=       64 usecs,    100, or   0.39%
Elapsed Time, >       64 usecs AND <=      128 usecs,     38, or   0.15%
Total,                                                 25890

the small svchost.exe spike comes from Superfetch.

[kilo85]

I fixed my problem!! To stop the spikes in Latmon i had to factory reset the BIOS, then go back and turn off SpeedStep, C1E Support, and C-STATE. These were all already turned off, but a factory reset on the BIOS and turning them back off again solved my 30 second spike problem in DPClat.

Even then I still had problems with LatMon, but I finally found out that the latency problem and the "Your system seems to have difficulty handling real-time audio and other tasks." error message was being caused by the "power" startup service!! disabling this service in msconfig means I now have no more problems, and im finally rid of that damned error msg!!

Still, Big thanks to MagicAndre for taking a look at my results and helping me route out that this was not a driver problem!

[doveman]

I seem to have "acquired" a DPC latency issue again. I'm also hearing a lot of random HDD activity for extended periods so maybe that's a clue. At the moment, it seems to be explorer.exe causing it, as that's using 10-15% CPU whilst everything else is idle. Defrag isn't scheduled and nor are there any other scheduled tasks I can see that would cause this disk activity. We previously fixed the DPC problem by plugging my mouse into the motherboard and not a hub but it's still plugged into the motherboard so shouldn't be causing any issues.

https://docs.google.com/file/d/0B1fDI89phEESeTRDZ3hyektqTWM/edit?usp=sharing

[MagicAndre1981]

the high Explorer cpu usage comes from

SearchFolder.dll!CGrepQuery::_CheckRecurseIntoFolder

the DPC issues come from the sptd.sys driver (Demon Tools)

Total = 368 for module sptd.sys
Elapsed Time, >        0 usecs AND <=        1 usecs,      2, or   0.54%
Elapsed Time, >        1 usecs AND <=        2 usecs,      1, or   0.27%
Elapsed Time, >        2 usecs AND <=        4 usecs,      0, or   0.00%
Elapsed Time, >        4 usecs AND <=        8 usecs,    239, or  64.95%
Elapsed Time, >        8 usecs AND <=       16 usecs,     87, or  23.64%
Elapsed Time, >       16 usecs AND <=       32 usecs,      5, or   1.36%
Elapsed Time, >       32 usecs AND <=       64 usecs,      1, or   0.27%
Elapsed Time, >       64 usecs AND <=      128 usecs,      1, or   0.27%
Elapsed Time, >      128 usecs AND <=      256 usecs,     25, or   6.79%
Elapsed Time, >      256 usecs AND <=      512 usecs,      0, or   0.00%
Elapsed Time, >      512 usecs AND <=     1024 usecs,      5, or   1.36%
Elapsed Time, >     1024 usecs AND <=     2048 usecs,      2, or   0.54%
Total,                                                   368

[doveman]

the high Explorer cpu usage comes from

SearchFolder.dll!CGrepQuery::_CheckRecurseIntoFolder

the DPC issues come from the sptd.sys driver (Demon Tools)

Thanks. I'll uninstall the sptd driver and use Alcohol 52% instead.

I note the driver tab of LatencyMon doesn't show sptd.sys very high up the list, so I guess that's not the useful for identifying the problem.

Regarding the Explorer usage, do you know what was triggering the SearchFolder function as I wasn't actively searching in Explorer at the time?

EDIT: Also, is it normal that latency is high when the HDD is busy, such as when defragging? I'm doing that at the moment and whereas normally it hovers around 19-30us but does spike to 100-200, whilst defragging it's minimum is about 160us going up to about 350us (the highest spike in the 3minutes I've been measuring was 2639us though).

Edited June 28, 2013 by doveman

[MagicAndre1981]

I have no idea what was triggering the SearchFolder function.

Yes, doing IO activty causes DPCs. If they are under 1000µs you should have no glitches.

[doveman]

I have no idea what was triggering the SearchFolder function.

Yes, doing IO activty causes DPCs. If they are under 1000µs you should have no glitches.

OK. As I said though, the highest spike was 2639us. I was defragging at the time and obviously don't care about latency whilst doing that but if HDD activity can cause such spikes, I imagine they could occur whilst a game is loading files from the HDD as well, which would be a problem.

[mpolo]

Not sure if this will help anyone but I came here during my diagnosis of similar DPC latency issues.

It was on a HP notebook (8540w)

At first it appeared to the the nvidia display driver but after uninstalling it then appeared to be the ataport.sys driver.

Eventually though, I saw a mention of a faulty power supply causing similar issues, the one hardware item I never suspected! Running on battery improved the situation, and using the same troublesome powersupply on another HP laptop slowed it right down.

With the new powersupply, latencymon is still saying that there _might_ be slowdowns, but from a benchmark perspective it is running normally again.

Something to keep in mind,

Michael