Windows 7- system using high CPU intermittently

[mcc]

EDIT-PROBLEM IS BACK-SEE POST 6 FOR SOLUTION

I'm having an annoying problem with Windows 7 Ultimate x64 RTM from the MS action pack. Every few minutes the System process uses 25% of the CPU or what I presume to be 100% of one core. I was able to track the thread down to "ntoskrnl.exe!KdPollBreakIn+0x1a0" in Process Explorer. The high CPU usage only lasts for about 15-20 seconds but it robs enough resources to make video lag behind by ~10 seconds. I'm running a speedy machine but I have FFDShow configured with lots of processing options.

Any insight?

[-=SparX=-]

Does the problem show up in different players ?
what version of ffdshow and or codec pack are you using and are you using x64 components ?

Have a look at shark007.net/ see if that solves anything.

[mcc]

It's not necessarily FFDShow that's the problem- the random CPU spike occurs at any time, the video processing lag is just one annoying result. I installed WPT from the Windows 7 SDK so I could use "xperf -on base" to track it down. Unfortunately it fails with "xperf: error: NT Kernel Logger: Cannot create a file when that file already exists. (0xb7)." How descriptive, esp. since no output file is specified.

Process Explorer running under administrative system credentials via psexec can't call up a stack trace, failing with "unable to access thread". That about exhausts all the relevant debug tools I know of...

[mcc]

The problem didn't exist in safe mode so I dumped a list of DLLs running under system in both normal and safe mode. After removing all Microsoft entries I had a list of potentially problematic drivers, among them VMWare. I uninstalled VMWare server 2 and the problem is solved.

[mcc]

I recently ran into this problem again- on my desktop AND on my laptop which is also now running Windows 7 x64. Neither has VMWare installed and the laptop has never had it.

On my desktop I ran Process Monitor and found that I have 1.3 million of the following events corresponding to the problem in less than 10 minutes:

Process: System
Operation: IRP_MJ_CREATE
Path: C:\Windows\System32\drivers\etc\lmhosts
Result: NAME NOT FOUND

I copied lmhosts.sam and renamed it as lmhosts, and now I get hundreds of thousands of these:

Process: System
Operation: IRP_MJ_CREATE
Path: C:\Windows\System32\drivers\etc\lmhosts

Process: System
Operation: FASTIO_QUERY_INFORMATION
Path: C:\Windows\System32\drivers\etc\lmhosts

Process: System
Operation: IRP_MJ_READ
Path: C:\Windows\System32\drivers\etc\lmhosts

Process: System
Operation: IRP_MJ_CLEANUP
Path: C:\Windows\System32\drivers\etc\lmhosts

Process: System
Operation: IRP_MJ_CLOSE
Path: C:\Windows\System32\drivers\etc\lmhosts

Process: System
Operation: FASTIO_ACQUIRE_FOR_SECTION_SYNCHRONIZATION
Path: C:\Windows\System32\drivers\etc\lmhosts

Process: System
Operation: FASTIO_RELEASE_FOR_SECTION_SYNCHRONIZATION
Path: C:\Windows\System32\drivers\etc\lmhosts

Stack trace for the failed IRP_MJ_CREATE operation:



Since I'm having this occur on two separate machines I'd venture a guess that this is some sort of bug with Windows 7 itself. The above events only occur during the CPU spikes.

Suggestions?

Thanks!

[mcc]

I think I've finally and completely solved the issue. After some deep digging I finally found KB955860 for W2k3. Apparently there's a semi-infinite loop bug wherein the machine makes a massive number of lookups to the LMHOSTS file on machines with multiple NICs. It would seem to appear that this also applies to Windows 7 RTM since the issue appears to have been solved by workaround 2- disabling LMHOSTS lookups altogether.

Again, this happens on two very different machines. The similarities between my laptop and desktop end with a Core2 architecture CPU, Intel chipset and ATI graphics. This seems to be a genuine bug that MS should look into fixing.

[HankyPanky]

Hi, I'm having almost the same problem. My CPU spikes to 100% usage and my PC kinda freezes for some secs, then goes back to normal. Can't find out what is happening, it's making me so frustrated. Searched all over the internet and cant find and answer, I'm desperate. I only notices it when I play games or watches movies, please help :/