MagicAndre1981

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

1,451 posts in this topic

I've only noticed this happening in the last week or so and the only thing I've done since then was move house. The only difference was that I used my phone as a modem for the first time ever - a lot of googling for the last few days has led me here but so far there are dozens of theories and no confirmed solutions. In my case, this is quite random. The process called 'System' (description NT Kernel and System) randomly seems to max out one core of the CPU then stops after a random amount of time. There's nothing in the event log for when this occurs.

I've run all the malware, AV, etc scans. Almost everyone with this problem that has reformatted and done a clean install says that the problem persists which indicates either hardware or a root kit. I've run 14 hours of memtest which came back clean and I've disabled my wireless card. Nothing has helped.

One thing that is interesting which I have found in all my research is that it may be related to IRQ settings. The reason I say this is that one time it occurred was while playing a game and the sound from my Creative SB X-FI went into a very short loop (about 50-100ms). There has also been a lot of talk about Interrupts, USB devices and hardware conflicts which all point at an IRQ problem. I have previously had my hardware working perfectly and then my sound card suddenly stop working for no reason and playing musical chairs with PCI cards changed the IRQ settings and fixed the problem. None of that explains the random nature of the current issue or why there has been a sudden increase in this problem recently.

My hardware is a Phenom II 965 with 4GB RAM, ATI 4850, X-FI Fatal1ty and TP-Link wireless-N card (can't remember the model number and I'm at work right now).

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you should run the xperf command I've posted here when the System- Process uses the CPU and look which driver causes the issue.

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Hi, I have come across this site trying to resolve the problem described in the first post. But, after downloading symbols, I am still getting an Module "Unknown" as the issue and I cant pin it down.

I have uploaded a rar here:

w2designs.dreamhosters.com/DPC_Interrupt.rar

which contains the elt file.

Thanks for any insight anyone can provide. I had daemon tools installed but it has been removed and I beleive these problems started before I had it installed anyway.

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Hi everyone,

I have spikes in CPU usage at fairly regular intervals when streaming video or playing a game full-screen.

I have done as MagicAndre has suggested and done a trace and found the USBport.sys is most likely the problem.

You mentioned updating chipset drivers, I think I did that but not sure if I did it correctly, I don't really understand the chipset thing.

Tried updating USB drivers, nVidia chipset? drivers and BIOS but still having problems.

Anyone able to help?

Let me know if there's any info you might need.

AMD athlon processors

ASUS M2N-VN DVI motherboard

nVidia chipset (nForce 560 and Southbridge nForce 630a) from CPU-Z

Windows 7 Pro 64bit

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yeah, install the latest nVIDIA nForce drivers.

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Hi everyone,

I have spikes in CPU usage at fairly regular intervals when streaming video or playing a game full-screen.

I have done as MagicAndre has suggested and done a trace and found the USBport.sys is most likely the problem.

You mentioned updating chipset drivers, I think I did that but not sure if I did it correctly, I don't really understand the chipset thing.

Tried updating USB drivers, nVidia chipset? drivers and BIOS but still having problems.

Anyone able to help?

Let me know if there's any info you might need.

AMD athlon processors

ASUS M2N-VN DVI motherboard

nVidia chipset (nForce 560 and Southbridge nForce 630a) from CPU-Z

Windows 7 Pro 64bit

Asus does not offer W7 32 or 64bit chipset drivers for that motherboard, they do offer them for Vista 64bit, and should work for W7, but they are dated 03/07/2008, they might work better than the default drivers W7 installed.

Choose Vista 64bit as the OS selection to download the chipset drivers.

http://support.asus.com/download/download.aspx?modelname=M2N-VM%20DVI&SLanguage=en-us

If found this on the Nvidia site, not sure it is the chipset driver though.

http://www.nvidia.com/object/nforce_vista64_15.23.html

.

Edited by NewestGuy
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System Specs:

Sapphire AMD 939 A9RD480Adv Motherboard (BIOS 6.0)

AMD Athlon 64 x2 4400+

ATI Radeon HD 4850(2) (Crossfire)

WD 500GB Hard drive(2) (Raid 0)

4Gigs RAM DDR

OCZ ModXtreme 600W Power Supply

Windows 7 32bit

Hi there. It seems as if I'm having the problem a few of you are having. I followed the instructions to the letter and have discovered that my amdk8.sys is causing the second core of my CPU to constantly run and peak at 100% usage. Upon further inspection, the function that is the culprit is C1HALT. I read in a few previous post that this is nothing to be alarmed about...but no solution has been stated as in how to fix this. If I wasn't a gamer or use graphically intense programs, then i wouldn't worry about it. But the CPU slow down is preventing me from taking advantage of the system that I've built.

As you can see from the sidebar gadget also, its causing my second core to constantly run around 100%. I have all the up to date drivers for my devices, the latest bios for my board (not much of an option here since my board is kinda old). So is there any fix to the C1HALT issue or am I just screwed and have to bite the bullet and do a total overhaul of my system with newer components? any help would be greatly appreciated.

Thanks in advance.

post-292167-127380247996_thumb.jpg

Edited by glmoreky
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Hello MagicAndre & friends,

I join this thread hoping you can help me improve my DPC latency. Back in XP SP3, DPC latency used to stick around 40-50 µs. Within win7 64, I don't have huge red spikes often, but yellow ones (1070 µs for example) happen quite easily, and overall my latency is in the 300-400 µs range, which feels too much and uncomfortable : this is supposed to be a fully functionnal DAW for me to earn a living with it.

Xperf shows an unknown module and it's function 0xfffffa8002fb20f0 which i suspect is reponsible for the situation. Please find with this post

a .txt summary of my PC

http://www.zshare.net/download/76065675ce27aac1/

a screen shot of DPC latency checker

dpctroubles.jpg

a screen shot of xperf's Summary table

summarytroubletable.jpg

http://www.zshare.net/download/76065675ce27aac1/

Best Regards.

Edited by ilove2learn
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@glmoreky

ignore the IDLE- Process. This doesn't create the CPU usage! The C1Halt command is a power saving feature.

@ilove2learn

sort for duration, not the count! Which DPCs take most time?

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@glmoreky

ignore the IDLE- Process. This doesn't create the CPU usage! The C1Halt command is a power saving feature.

@ilove2learn

sort for duration, not the count! Which DPCs take most time?

Well if I post a screen shot of the whole table, before the break downs, could you possibly tell me whats going on and whats causing this?

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I took another look at the table and saw that my problem was being caused by USBPORT.sys. I tried to update the driver...still problem remained. So I went to my local computer store and purchased a USB card for $17.00USD. Plugged it in and let windows find it and install drivers. Restarted my computer and the problem is now resolved. Thank you for posting the tutorial. Wish I would have found this when the problem first occurred. Would have saved me 6 days of headaches lol.

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Potentially - from the screenshot we have, the largest consumer (by far) of DPC time is ndis.sys calling ndisInterruptDPC, meaning the network driver is indeed responsible for some of that time. If the network miniport driver registered itself an ISR handler, it either shares an IRQ with another device or the driver must capture interrupt-specific data from NIC registers at DIRQL - both would cause calls into this API.

It would be best if we had access to the data set itself, but a screenshot is better than nothing :).

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@glmoreky

great, that you found the cause with the help of this guide :)

@cluberti

any ideas about the unknown module? How can I detect which driver it is?

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@ilove2learn

sort for duration, not the count! Which DPCs take most time?

As i tried to update my PC since previous post, i did a new xperf. Here is it's summary table :

dpc14may201019h22.jpg

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upload the etl file and post the link here.

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