Off-load Registry Keys

This group of registry keys allows the administrator to specify which TCP/IP offload settings are handled by the adapter rather than by the operating system.

Enabling offloading services increases transmission performance. Due to offload tasks (such as checksum calculations) performed by adapter hardware rather than by the operating system (and, therefore, with lower latency). In addition, CPU resources become more available for other tasks.

Value Name

Default Value

Description

*LsoV1IPv4

1

Large Send Offload Version 1 (IPv4). The valid values are:

  • 0: disable

  • 1: enable

*LsoV2IPv4

1

Large Send Offload Version 2 (IPv4). The valid values are:

  • 0: disable

  • 1: enable

*LsoV2IPv6

1

Large Send Offload Version 2 (IPv6). The valid values are:

  • 0: disable

  • 1: enable

LSOSize

eth:64000 IPoIB:64000

The maximum number of bytes that the TCP/IP stack can pass to an adapter in a single packet.

This value affects the memory consumption and the NIC performance.

The valid values are MTU+1024 up to 64000.

Note: This registry key is not exposed to the user via the UI.
If LSOSize is smaller than MTU+1024, LSO will be disabled.

LSOMinSegment

eth:2 IPoIB:2

The minimum number of segments that a large TCP packet must be divisible by, before the transport can offload it to a NIC for segmentation.

The valid values are 2 up to 32.

Note: This registry key is not exposed to the user via the UI.

LSOTcpOptions

eth:1 IPoIB:1

Enables that the miniport driver to segment a large TCP packet whose TCP header contains TCP options.

The valid values are:

  • 0: disable

  • 1: enable

Note: This registry key is not exposed to the user via the UI.

LSOIpOptions

eth:1 IPoIB:1

Enables its NIC to segment a large TCP packet whose IP header contains IP options.

The valid values are:

  • 0: disable

  • 1: enable

Note: This registry key is not exposed to the user via the UI.

*IPChecksumOffloadIPv4

eth:3 IPoIB:3

Specifies whether the device performs the calculation of IPv4 checksums.

The valid values are:

  • 0: (disable)

  • 1: (Tx Enable)

  • 2: (Rx Enable)

  • 3: (Tx and Rx enable)

*TCPUDPChecksumOffloadIPv4

eth:3 IPoIB:3

Specifies whether the device performs the calculation of TCP or UDP checksum over IPv4.

The valid values are:

  • 0: (disable)

  • 1: (Tx Enable)

  • 2: (Rx Enable)

  • 3: (Tx and Rx enable)

*TCPUDPChecksumOffloadIPv6

eth:3 IPoIB:3

Specifies whether the device performs the calculation of TCP or UDP checksum over IPv6.

The valid values are:

  • 0: (disable)

  • 1: (Tx Enable)

  • 2: (Rx Enable)

  • 3: (Tx and Rx enable)

ParentBusRegPath

HKLM\SYSTEM\CurrentControlSet\
Control\Class\{4d36e97d-e325-11ce-bfc1- 08002be10318}\0073

TCP checksum off-load IP-IP.

*RssOnHostVPorts

1

Virtual Machine Multiple Queue (VMMQ) HW Offload

The valid values are:

  • 0: disable

  • 1: enable

© Copyright 2023, NVIDIA. Last updated on May 23, 2023.