Receive Side Scaling (RSS)

Operating Systems: Windows Server 2012, Windows Server 2012 R2, Windows 7 Client, Windows 8.1 Client and Windows Server 2016.

Mellanox WinOF Rev 5.50 IPoIB and Ethernet drivers use NDIS 6.30 and above new RSS capabilities. The main changes are:

  • Removed the previous limitation of 64 CPU cores

  • Individual network adapter RSS configuration usage

RSS capabilities can be set per individual adapters as well as globally.

To do so, set the registry keys listed below:

For instructions on how to find interface index in registry <nn>, please refer to Section 3.6.2, “Finding the Index Value of the Network Interface”, on page 114.

Registry Keys Setting

Sub-key

Description

HKLM\SYSTEM\CurrentControlSet\Control\Class\{4d36e972-e325-11ce-bfc1-08002be10318}\<nn>\*MaxRSSProcessors

Maximum number of CPUs allotted.
Sets the desired maximum number of processors for each interface. The number can be different for each interface.
Note: Restart the network adapter after you change this registry key.

HKLM\SYSTEM\CurrentControlSet\Control\Class\{4d36e972-e325-11ce-bfc1-08002be10318}\<nn>\*RssBaseProcNumber

Base CPU number.
Sets the desired base CPU number for each interface. The number can be different for each interface. This allows partitioning of CPUs across network adapters.
Note: Restart the network adapter when you change this registry key.

HKLM\SYSTEM\CurrentControlSet\Control\Class\{4d36e972-e325-11ce-bfc1-08002be10318}\<nn>\*NumaNodeID

NUMA node affinitization

HKLM\SYSTEM\CurrentControlSet\Control\Class\{4d36e972-e325-11ce-bfc1-08002be10318}\<nn>\*RssBaseProcGroup

Sets the RSS base processor group for systems with more than 64 processors.

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