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Hyper-V CPU when using the network RRS feed

  • Question

  • Hi, I have an issue with high CPU usage when doing anything involving the network on a Guest XP client.

    File copies from a network share cause the system process to rise to around 40% and explorer to take the final 60%

    Also when steaming video of around 15-20Mbit/sec the CPU usage will rise to 100% and cause the video to stutter.  With streaming the system process rises to 80%



    My set-up is as follows, Server 2008 RTM fresh install + Patches.  Single XP SP3 VM + integration pack.
    The issue has been tested with the synthetic NIC and legacy NIC

    The network has been tested with 100Mbit and 1000Mbit

    I also tried the Server Core installation.

    Of all my testing only the change to Gig networking reduced the stutter when streaming, but the CPU usage issues remain.

     

     

    I have repeated the test on two platforms firstly a HP Ml115 Quad core Opteron with 8GB Ram.  Locally attached SATA HDD, Onboard NIC and an Intel Pro 1000 PT.

    Second hardware was a desktop Core 2 Duo 6400 with 2GB ram, SATA HDD and Onboard NIC and a Intel Pro 1000 PT.

     

    No antivirus software is installed and I have tried turning off the TCP offloading features.

     

    To prove that there wasn’t another faulty link somewhere I repeated the tests but with ESXi VM Software on the same hardware and all of my tests where successful with only 10% CPU usage for the network tests.

    Friday, March 20, 2009 10:27 AM

Answers

  • When you say that it maxes the guest CPU and causes stuttering.

    How are you observing the guest console?

    If you are at the Hyper-V console and are viewing the guest console from the Hyper-V manager, you are adding additional overhead to the host becuase you are using the RDP proxy feature of Hyper-V to view the guest console.

    If that is the case, attemp to RDP directly into the guest and see what happens.
    You could even attempt to use VNC or ICA (if you have XenDesktop).

    Also, John has also extensively pointed out a vTPR issue with WinXP clients on specific host chipsets.  The end result is greatly decreased WinXP VM performance.
    (I will leave it open for him to chime in)


    (BTW - why try ESXi and not XenServer?  At least XenServer is similar architecture, where ESX is a different virtualization model)
     

    Brian Ehlert (hopefully you have found this useful)
    • Edited by BrianEhMVP Friday, March 20, 2009 3:04 PM q
    • Marked as answer by Vincent Hu Monday, March 30, 2009 8:25 AM
    Friday, March 20, 2009 3:02 PM

All replies

  • Networking activity does increase cpu activity. Networking has been improved in the R2 version of Hyper-V.
    Friday, March 20, 2009 12:01 PM
  • Im glad to hear that the general area is being looked at,
    However I feel that 15 -20 Mbit of traffic when using the Intergration pack should not max the Guest CPU, so much so that it causes stuttering of streaming media.
    Friday, March 20, 2009 2:42 PM
  • When you say that it maxes the guest CPU and causes stuttering.

    How are you observing the guest console?

    If you are at the Hyper-V console and are viewing the guest console from the Hyper-V manager, you are adding additional overhead to the host becuase you are using the RDP proxy feature of Hyper-V to view the guest console.

    If that is the case, attemp to RDP directly into the guest and see what happens.
    You could even attempt to use VNC or ICA (if you have XenDesktop).

    Also, John has also extensively pointed out a vTPR issue with WinXP clients on specific host chipsets.  The end result is greatly decreased WinXP VM performance.
    (I will leave it open for him to chime in)


    (BTW - why try ESXi and not XenServer?  At least XenServer is similar architecture, where ESX is a different virtualization model)
     

    Brian Ehlert (hopefully you have found this useful)
    • Edited by BrianEhMVP Friday, March 20, 2009 3:04 PM q
    • Marked as answer by Vincent Hu Monday, March 30, 2009 8:25 AM
    Friday, March 20, 2009 3:02 PM
  • The Media stuttering is observed on a physical client the media is being streamed to.  CPU history shows that the CPU his very high during the streaming at around 80% to 100%.
    Its slight worse when observed via the Hyper-V console, I’ve not noticed if RDP helps due to it still stuttering when unmonitored.

    On the vTPR issue, I haven’t read anything about this with Opteron processers, but perhaps that’s more due to market penetration than anything else.

    (XenServer is something i’ve had no experience of in the past, where as I can get a ESXi running in 30 minutes)

    Friday, March 20, 2009 3:48 PM
  • Hi, you can install another system like Vista to test if the same issue occur.
    Monday, March 23, 2009 6:08 AM