Checksum offloads and protocol ossification
Checksum offloads and protocol ossification
Given the processing requirements for high-speed networking, it is not surprising that there is interest in offloading some of that work to dedicated hardware. Linux has always carefully limited the support provided for such offloading, though; it has been just over ten years since support for TCP offload engines was definitively blocked from entering the Linux network stack. That rejection was driven by a number of concerns, with a reluctance to entrust network-protocol processing to closed-source, unextendable, unfixable software being near the top of the list. Nearly ten years later, offload engines are again the topic of fierce discussion. The hardware has changed, but the concerns have not; indeed, some of the problems being worked around now show why those concerns were valid in the first place.