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davodavo
Posts: 39
Registered: ‎02-22-2008
Location: San Francisco, CA USA
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Re: Access Connections 5.62 on WinXP pro SP3 high CPU utilization (SVCHOST)

OK, did the RegMon thing, just looking at the hits from SVCHOST processes.

 

During the peak CPU period right after AC completes the WIFI connection, there are about 2500 hits to the registry by SVCHOST processes.  Interestingly, three separate SVCHOST processes are in there during this period, but probably 60% of it is the DNS client SVCHOST. 

 

Literally hundreds of keys are being worked, but there doesn't appear to be any rediculous loops where a few keys are being repeatedly changed.  I filtered for CurrentControlSet, and didn't notice anything horrendous.  While there are some things in there I can probably optimize (like, turning off Upnp), it doesn't seeem that I'll shave more than a few ms off with any single change.  But I'm hardly a network wiz -- there may be larger patterns I don't see.  I'm kind of curious why the software is trying to query all kinds of keys relating to an interface that isn't even active (ethernet...find it in the log by searching for the string 7FE23)

 

I'm posting the comoplete log for anyone who wants to analyze it at: 

www.sfdc-secrets.com/taberconsulting/RegmonAC.txt

 

Ideas?

gan
Posts: 903
Topics: 4
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Registered: ‎11-26-2008
Location: Norway
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Re: Access Connections 5.62 on WinXP pro SP3 high CPU utilization (SVCHOST)

[ Edited ]

 

I was looking at the file you posted and couldn't see any problems really. I did not see the same kind of behavior i had. There is a lot of odd activity in the registry and seems like that is usually just normal behavior. I also wonder sometimes what is actually going on in there :smileyhappy:

 

After doing som searching i also found several posts with similar problem because of the hosts file. Did you ever modify the hosts file and if yes could you try to change it back to default again?

 

Default it should look something like this:

 

# Copyright (c) 1993-2009 Microsoft Corp.
#
# This is a sample HOSTS file used by Microsoft TCP/IP for Windows.
#
# This file contains the mappings of IP addresses to host names. Each
# entry should be kept on an individual line. The IP address should
# be placed in the first column followed by the corresponding host name.
# The IP address and the host name should be separated by at least one
# space.
#
# Additionally, comments (such as these) may be inserted on individual
# lines or following the machine name denoted by a '#' symbol.
#
# For example:
#
#      102.54.94.97     rhino.acme.com          # source server
#       38.25.63.10     x.acme.com              # x client host

# localhost name resolution is handled within DNS itself.
127.0.0.1       localhost

All the lines that start with # is just comments. Some silly security programs create a whole bunch of entries in the hosts file so even if you did not make changes to the hosts file manually it could happen using these kind of applications as well. I belive if you have too many entries in the hosts file you could see issues where the svchost.exe use a lot of CPU. The hosts files should be located under "%windir%\System32\drivers\etc".

 

-gan

gan
Posts: 903
Topics: 4
Kudos: 110
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Registered: ‎11-26-2008
Location: Norway
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Re: Access Connections 5.62 on WinXP pro SP3 high CPU utilization (SVCHOST)

Seems like a lot of people had this problem because of windows update as well so you could try to temporarily disable the automatic update service under services to see if that solve the problem. There are some updates available to fix this problem, but i believe these fixes should be included with SP3 anyway so they are most likely not relevant for you. This problem seems to be a pretty old one so most likely not relevant for XP SP3.

 

Also several people solved this by disabling the DNS client service, but that will disable DNS caching and you have to query the DNS a lot more which will probably slow down the loading of webpages on the internet. So not a recommended permanent solution i think, but it might fix the high CPU. If you have a huge hosts file as explained in my previous post i would rather recommend to cleanup that file instead of disabling services and so on. If an application you use is filling up the hosts file i would recommend to uinstall that program since they usually cause more problems than it will do any good.

 

-gan

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davodavo
Posts: 39
Registered: ‎02-22-2008
Location: San Francisco, CA USA
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Re: Access Connections 5.62 on WinXP pro SP3 high CPU utilization (SVCHOST)

Thanks for all the analysis...and yes, I have an enormous hosts file.  The file has a ton of domains pointing straight to 127.0.0.1, which should actually lighten the load for DNS.

 

I did a FileMon run, and here's what I found about SVCHOST file touches during the CPU storm:  about 5 seconds of the total time was spent reading the hosts file.

 

I'll try the empty hosts file next time I reboot, but I doubt it'll make a giant difference.

 

gan
Posts: 903
Topics: 4
Kudos: 110
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Registered: ‎11-26-2008
Location: Norway
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Re: Access Connections 5.62 on WinXP pro SP3 high CPU utilization (SVCHOST)

[ Edited ]

davodavo wrote:

 

I'll try the empty hosts file next time I reboot, but I doubt it'll make a giant difference.

 


Well i might be wrong, but actually i think this is the problem and empty the hosts file will fix the problem. A lot of others report the same problem with a huge hosts file. It's a textfile and no index like when using a real database so will become slow with a lot of entries. The hosts file is not designed to replace the DNS server, but more like adding a few entries. Windows will search that file before asking the DNS server for each address. Since your problem occur each time you switch profiles in AC it might sound a bit strange this should be relevant, but since it's the svchost.exe / dns client service that cause the high CPU problem it sounds like the huge hosts file is exactly the problem here.

 

As i said i might be wrong, but i would recommend to give it a try and i'm pretty sure it will make a difference. There are different reasons why some use such a program that fill up the hosts file, but using such a program for security reasons and my opinion is it's a false sense of security.

 

While a huge hosts file will lighten the load of the DNS server it will kill your computer. A DNS server should normally be fast and able to handle a whole lot of DNS requests so i doubt this will make much difference for the DNS server, but your computer will suffer. If the DNS server cannot handle your requests there is a problem with the DNS server. One reason why this will make your computer slower is the high CPU of course, but also since Windows have to search this hosts file for each address before asking the DNS which is a lot slower than asking the DNS right away and get a reply unless you have some serious network issues or serious DNS problems.

 

Either way filling the hosts file to lighten the load of the DNS i think is a bad idea.

 

-gan

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davodavo
Posts: 39
Registered: ‎02-22-2008
Location: San Francisco, CA USA

Re: Access Connections 5.62 on WinXP pro SP3 high CPU utilization (SVCHOST)

OK, so in the interests of science I went back to an essentially-empty Hosts file.

 

And you were right:  SVCHOST phenomenon essentially disappeared.

 

So, we gotta call this one SOLVED (DNS client parameters and shorten the HOSTS file).

gan
Posts: 903
Topics: 4
Kudos: 110
Solutions: 108
Registered: ‎11-26-2008
Location: Norway
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Re: Access Connections 5.62 on WinXP pro SP3 high CPU utilization (SVCHOST)

Glad to hear we finally found the solution to fix the problem :smileyhappy:

 

-gan