On Fri, 28 Nov 2025 15:42:40 -0500 Willem de Bruijn wrote:
- elif mode == "lro":
_set_ethtool_feat(cfg.ifname, cfg.feat,{"generic-receive-offload": False,So GRO off disables HW_GRO, but not LRO? That difference is behavior is confusing. Could we still see this as a regression and make the ethtool HW_GRO feature equally independent from SW_GRO?
I couldn't convince myself that it's justified. Of course it would have made testing a lot easier. But apart from that - what's your reading of the status quo? Working backwards from were we ended up (and I haven't dug into the git history) I'm guessing that LRO disable is used to prevent changing geometry of the packets. GRO would presumably be disabled when user knows that it will be ineffective, to save the cost. Or when some portion of the stack (XDP?) can't deal with super frames.
If those are the reasons, practically, I don't see why user would want HW GRO without SW. Ever since we allowed SW GRO to re-GRO HW GRO'ed frames it's always better to leave SW enabled. HW leaves a lot of aggregation opportunities on the table.
I concluded that changing the current behavior would not help any real life scenario, just testing. LMK if you see one or the inconsistency is a big enough reason.