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by yokaze 1062 days ago
It's different. Rdma offloads the TCP transfer of host memory to the network device. This is about transferring device memory directly, avoiding going though the host.

Had to read through the lklm message, at it wasn't clear from the article.

2 comments

RDMA does not offload TCP. Furthermore it's not limited to between NIC memories - for example GPU memory to remote GPU memory works as well.
From what I remember of Infiniband, the network cards are able to do direct PCIe transfers to/from compatible devices attached to the host (eg nvidia quadro gpus).

Specifically to avoid bogging down the host.

precisely this. The reason why its worth the expense is that data entering the network is guaranteed to come out the otherside. This kinda eliminates the need for TCP (apart from addressing)