Does Checksum Offloading affect latency in a good way? Does it vary depending on cpu power?
Sophia Terry 
I'm trying to get an understanding of the settings that you see when you go to the advanced options of a typical intel or realtek networking card in your windows device manager. A lot of those are different kinds of checksum offloading: ipv4 checksum offload, large send offload, tcp checksum offload, udp checksum offload.
Is there an absolute answer to whether they should be enabled or disabled or does it vary based on any kind of parameters?
As far as I understand, these offloads offload certain tasks from the cpu to the network card. If we assume that the card performs these tasks without bugs (some people say that in the past certain card were buggy with those offloads), is this then an improvement towards throughput/latency? What if the cpu is very powerful with high clock rate etc. (example ryzen 5950x or intel 10900/11900k), would it still be an improvement to offload them to the networking card?
Any explanation would be appreciated. These offloads have always been confusing me.
1 Answer
The Microsoft article from May 2021,Hardware Only (HO) features and technologies, has this advice:
Address Checksum Offloads should ALWAYS be enabled no matter what workload or circumstance. This most basic of all offload technologies always improve your network performance. Checksum offloading is also required for other stateless offloads to work including receive side scaling (RSS), receive segment coalescing (RSC), and large send offload (LSO).
However, offloading has been known to cause some issues, and disabling it can help avoid these issues.
There are no rules - in several posts on our site, disabling it has solved some problem. In others, enabling it has solved other problems.
The only absolute answer I can give is: It is enabled by default, if the network adapter has this capability, and should only be turned off if doing so solves a problem with some particular hardware. Disabling it will impact many other networking mechanisms with negative effect.
3
