From KVM
Line 8: Line 8:
  
 
[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\AFD\Parameters]
 
[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\AFD\Parameters]
 +
 
"DefaultSendWindow"=dword:00100000
 
"DefaultSendWindow"=dword:00100000
 +
 
"DefaultReceiveWindow"=dword:00100000
 
"DefaultReceiveWindow"=dword:00100000
 +
 
"FastSendDatagramThreshold"=dword:00004000
 
"FastSendDatagramThreshold"=dword:00004000
  
  
 
[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters]
 
[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters]
 +
 
"Tcp1323Opts"=dword:00000001
 
"Tcp1323Opts"=dword:00000001
 +
 
"TcpWindowSize"=dword:00100000
 
"TcpWindowSize"=dword:00100000
 +
  
 
* Tcp1323Opts - allows the scaling of the TCP window above 16k. For more info read [http://technet.microsoft.com/en-us/library/cc938205.aspx Tcp1323Opts]
 
* Tcp1323Opts - allows the scaling of the TCP window above 16k. For more info read [http://technet.microsoft.com/en-us/library/cc938205.aspx Tcp1323Opts]

Revision as of 10:22, 10 August 2009

Windows registry settings

This page describes best practice for configuring Windows TCP\IP related parameters to archive the best performance with Windows guests. Those parameters are unrelated to kvm\VirtIO drivers , rather general Windows settings. After changing those setting reboot is required for the changes to effect the system.

Registry settings

[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\AFD\Parameters]

"DefaultSendWindow"=dword:00100000

"DefaultReceiveWindow"=dword:00100000

"FastSendDatagramThreshold"=dword:00004000


[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters]

"Tcp1323Opts"=dword:00000001

"TcpWindowSize"=dword:00100000


  • Tcp1323Opts - allows the scaling of the TCP window above 16k. For more info read Tcp1323Opts
  • "DefaultSendWindow", "DefaultReceiveWindow" and "TcpWindowSize" control TCP window size
  • "FastSendDatagramThreshold" - controls fast UDP transmit.

Additional links