Disable TCP Chimney Offload

Owned by Bruno Miretti (Deactivated)
Last updated: Feb 12, 2024 by W.ErberVersion comment
4 min read


Operating systemNotesCharon versionConfiguration steps

Windows Server 2019

TCP Chimney offload is disabled by default (deprecated technology)
  • Charon-AXP/PDP/VAX V4.11 Build 204-03 and above
None

Windows Server 2008 R2

Windows Server 2012 R2

Windows Server 2016

Windows 7

Windows 8 & 8.1

Windows 10

TCP Chimney offload must be disabled.

Note:

  • TCP Chimney Offload is a networking technology that helps transfer the workload from the CPU to a network adapter during network data transfer.
  • The commands to enable and disable TCP Chimney Offload for specific applications and ports require that the Windows Firewall service and Base Filtering Engine (BFE) services are running. Before using these commands or the Network Control Center Utility, ensure that the Windows Firewall service and BFE service are running.

(warning) Running guests will have to be powered off/on for the new settings to be taken into account.


(lightbulb) To check TCP Chimney offload is disabled, use the following commands:

C:\Windows\system32>netsh int tcp show global
Querying active state... 

TCP Global Parameters
----------------------------------------------
Receive-Side Scaling State          : enabled
Chimney Offload State               : disabled
NetDMA State                        : disabled
Direct Cache Access (DCA)           : disabled

...

(grey lightbulb) To revert back to the original settings manually, use the following command:

C:\Windows\system32>netsh int tcp set global chimney=automatic
  • CHARON-VAX V4.7 and CHARON-AXP V4.7 Build 171-10 and above (patched)
  • Charon-AXP/PDP/VAX V4.8 Build 183-02 and above (patched)
Configuration type 1

Older versions of Charon-AXP/PDP/VAX


(warning) Do not use the network control center utility to disable TCP chimney offload. Please use only the manual settings described in this chapter

Configuration type 2
Older versions of Windows

(warning) Running guests will have to be powered off/on for the new settings to be taken into account

Charon-AXP/PDP/VAX versions supported on these old versions of WindowsConfiguration type 3


Configuration type 1
  • Charon-AXP/VAX V4.7:
    • open the Start menu, select "All Programs" then "CHARON", select your Charon product version, "Utilities" then "Network Controler Center version x.xx".
  • Charon-AXP/PDP/VAX V4.8:

    • Double click the "CHARON Virtual Machine Manager" icon on desktop or select this utility in the tray menu; select "Host Information and Utilities" section and press "Network Control Center" button.

      .

  • From the "Network Control Center" utility main page, select the "Disable TCP chimney offload for CHARON" option:


  • Click on the "Next" button.

    .

  • The TCP Chimney offloading will be disabled:


  • Click on the "Finish" button to exit.
Configuration type 2
  • Open a command line windows with Admin rights

  • Issue the following command:

    C:\> netsh int tcp set global chimney=disabled

  • Delete all occurrences of Charon executables in the following table if any as described below:

    C:\> netsh interface tcp show chimney
    ...
    C:\> netsh interface tcp delete chimneyapplication ^
    More? application="C:\Program Files\CHARON\Build_16400\x64\as1000.exe"

Configuration type 3

Intelligent packet processing should be switched off for the network adapters dedicated to CHARON-AXP (naming of the parameters depends on the network adapter driver):

  • Adaptive interframe spacing

  • Flow control

  • Interrupt moderation

  • Interrupt moderation rate

  • Ipv4 checksum offload

  • Jumbo packet

  • Large send offload

  • Disable Priority and VLAN

  • TCP checksum offload

  • UDP checksum offload

To do so, open the "Control Panel", select "Network and Internet" and "Network Connections". Right click on the adapter you dedicated to CHARON, select "Properties" and click on the "Configure" button. Select the "Advanced" tab and disable the properties mentioned in the list above.

Once all parameters have been turned off, click on the "OK" button.

Example:


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