In general it may be good idea to use VXLAN offload inorder to decrease the CPU load by offloading VXLAN decoding to the NIC Card. This may also provde throughput, but the NIC card driver version and some features may be important. For UCS VIC 1340 the version after 3.1(2) supports Receive Site-Scaling for ESXi 6.0 and later.
nsx throughput
Confirm if the DRIVER supplied by your hardware vendor supports such features as VXLAN TSO and RSS.
https://www.cisco.com/c/en/us/td/docs/unified_computing/ucs/release/notes/VIC/3-1/b_CiscoVIC_Drivers...
https://supportforums.cisco.com/t5/unified-computing-system/vxlan-offload-support-for-esxi-6-0/td-p/...
The driver that supports RSS with VXLAN has been developed which allows hashing to be done on the inner frame for better network performance. This was released as you mentioned in 3.1(2).
Release 3.1(2) adds support for the following:
- Cisco UCS Manager 3.1(2) and higher now supports Virtual Volume Support for ESXi.
- Consistent Device Naming (CDN) support has been expanded to include Red Hat Enterprise Linux 6.X and Red Hat Enterprise Linux 7.X.
- Cisco UCS Manager 3.1(2) release now supports VXLAN with Receive Side-Scaling (RSS) stateless offload on VIC adapters 1340, 1380, 1385, 1387, and SIOC on Cisco UCS C3260 for ESXi 6.0 and later releases. VXLAN offload is not supported for IPv6.
- FNIC tunables now has two new options that are available for fiber channel adapter policies for Windows environments. This new feature only works with UCS Manager version 3.1(2) and higher with the FNIC driver (2.4.0.19).
- IO Retry Timeout — This option adjusts the IO retry timeout after a pending command expires on a network device.
- LUN Queue Depth — This setting adjusts the initial queue depth for all LUNs on the adapter.
