High DPC/Interrupt usage when transfer file/download
ive been getting about 15% CPU usage from DPC/ISR service (Deferred Procedure Calls / System Interrupts) when copying files from the HDD to external devices and vice versa and when I download files to computer, the downloading part of it gets worse if I install a firewall like Outpost (it went up to 40% when downloading at 12Mbps on my wifi with Outpost on - ive since uninstalled it) - so originally I though it was my wifi card but it does this with it disabled when i transfer files out to HDD (when I transfer files internally it doesnt happen) - I ran the Windows SDK Performance Monitor which showed it to be the NDIS.SYS that caused most of the problem. ive searched and asked for help on other forums but had no luck, one person told me its a bug in windows 7 and everyone gets it?? like I say it happens when downloading (the faster the more it does it and it does it more on Wifi (15%) than LAN (5%) and it happens when I copy files in/out of laptop's HDD - ive been told this 'hidden' process using even 1% is abnormal the process is hidden in Task manager and does not show so dont use that to check, even if this background service uses 99% cpu taskman will still show as 99% idle (it runs behind idle as its not expected to use more than 1% cpu...so im told) - only in resource monitor or process explorer can you see it see my screenshot below for example can anyone help me with this please? Win7-64bit / Dual-Core AMD / 2Gb / Acer Aspire 5050 laptop http://lookpic.com/i/600/rfO1pOiS.jpeg
March 31st, 2010 4:06pm

Hi, Based on my research, I would like to suggest the following: 1. Ensure all the device drivers are for Windows 7 and up-to-date. 2. Completely move the NICs, reboot the computer and install them with the latest version of their Windows 7 drivers. 3. Unplug all the unnecessary devices and have a try. 4. Boot the computer to clean boot and check the issue: How to troubleshoot a problem by performing a clean boot in Windows Vista or in Windows 7 5. Update the system BIOS. Hope this helps. Thanks. Nicholas Li - MSFT
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April 2nd, 2010 12:22pm

Hi, follow my guide here: http://www.msfn.org/board/index.php?showtopic=140263 which driver is the cause?"A programmer is just a tool which converts caffeine into code" CLIP- Stellvertreter http://www.winvistaside.de/
April 2nd, 2010 6:10pm

Andre, Hi I have the same long DPC latency when using IE8 , and especialy downloading files. I used your proposed method to trace it to NDIS.sys. I thought it might be a nework driver problem to begin with, and this confirmed it. http://img29.imageshack.us/img29/4485/dpcg.jpg I have an Intel DH55HC board with a i7 860 CPU and 8GB of RAM, running WIndows 7 ultimate x64 I have the latest BIOS, and the latest NIC driver from Intel. It's very frustrating because when I DL anything, my state of the art PC just freezes until the DL finishes. Any suggestions? Thanks
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October 13th, 2010 3:48am

Which network card do you use? "A programmer is just a tool which converts caffeine into code" CLIP- Stellvertreter http://www.winvistaside.de/
October 13th, 2010 7:30am

It's the Intel onboard card: 82578DC Gigabit Network Connection. Driver date 12.4.2010, version 11.6.92.0 , Provider - Intel. The strange thing is that the problem is not constant: When i boot the PC it works fine for an inconstant period of time, and suddenly starts to freeze when I surf or download. I also used DPC latency checker v1.20. - the average latency is usually below 2000 microsecond but above the 500 which is the normal. When the really high latency starts it reaches 8000 microsecond.
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October 13th, 2010 2:04pm

have you tried a different card?"A programmer is just a tool which converts caffeine into code" CLIP- Stellvertreter http://www.winvistaside.de/
October 13th, 2010 4:47pm

No. I've never had problems with Intel boards/NICs before. Which card would you recommend, Realtek?
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October 13th, 2010 5:39pm

I tried an old PCI NIC - Realtek 8139 - now the problem has not reccured for a few days. When using DPC latency checker, I find that starting network flow produces a high DPC latency peak(s), but it soon levels off. There is no noticable slowdown of the PC during the short peak: http://img251.imageshack.us/img251/5182/dpc3.jpg http://img832.imageshack.us/img832/7034/dpc2.jpg I've posted a question on INtel communties: http://communities.intel.com/thread/16622
October 16th, 2010 6:04am

I tried an old PCI NIC - Realtek 8139 - now the problem has not reccured for a few days. ok, so it's an issue with the Intel card."A programmer is just a tool which converts caffeine into code" CLIP- Stellvertreter http://www.winvistaside.de/
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October 16th, 2010 9:52am

Mostly yes, though I still get periods of high latency DPC, just not to the extenet of the INtel card, and my PC doesn't freeze. But if I listen to music on WMP it might stuttre momenterly, while internet traffic is heavy. http://img838.imageshack.us/img838/4364/dpc4.jpg
October 16th, 2010 11:27am

can you give me the trace file?"A programmer is just a tool which converts caffeine into code" CLIP- Stellvertreter http://www.winvistaside.de/
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October 16th, 2010 2:42pm

Is there a way to send it privately?
October 16th, 2010 2:56pm

register at msfn.org and send me a private message."A programmer is just a tool which converts caffeine into code" CLIP- Stellvertreter http://www.winvistaside.de/
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October 16th, 2010 3:21pm

I registerd on msfn.org . How do I find you there?
October 16th, 2010 3:34pm

I'm the author of this guide: http://www.msfn.org/board/index.php?showtopic=140263 go to my profile and send me a message."A programmer is just a tool which converts caffeine into code" CLIP- Stellvertreter http://www.winvistaside.de/
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October 16th, 2010 3:45pm

I sent you the trace with the Intel NIC.
October 16th, 2010 4:10pm

you've send me the kernel.etl. I need the merged DPC_latency.etl."A programmer is just a tool which converts caffeine into code" CLIP- Stellvertreter http://www.winvistaside.de/
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October 16th, 2010 5:48pm

That's the only etl file on my drive.
October 16th, 2010 6:02pm

you must run the xperf command with the d parameter to write the data into the new file."A programmer is just a tool which converts caffeine into code" CLIP- Stellvertreter http://www.winvistaside.de/
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October 17th, 2010 8:44am

Hi, Based on my research, I would like to suggest the following: 1. Ensure all the device drivers are for Windows 7 and up-to-date. 2. Completely move the NICs, reboot the computer and install them with the latest version of their Windows 7 drivers. 3. Unplug all the unnecessary devices and have a try. 4. Boot the computer to clean boot and check the issue: How to troubleshoot a problem by performing a clean boot in Windows Vista or in Windows 7 5. Update the system BIOS. Hope this helps. Thanks. Nicholas Li - MSFT Hi Nicholas, I have tried all of your suggestions without success. I even added a Realtek NIC - the problem is less noticable then with the Intel onbard NIC, but is still there. As I've mentioned above I tracked the problem to NDIS.SYS . The problem appears to be related to W7 x64 and Intel & Realtek chipsets. On an nForce NIC I don't see the problem. There are others with the same problem http://www.sevenforums.com/network-sharing/52935-network-usage-causes-high-dpc-latency.html Can you suggest a workaround? Thanks
October 29th, 2010 3:48am

Still waiting for Intel support to solve this. In the mean time I found a way to restore normal DPC latency without rebooting: Go to Services and restart Base Filtering Engine. After this you need to restart Windows firewall from the Action Center in the systray .
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November 6th, 2010 12:47pm

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