X520 live as the product NIC: rate buckets re-keyed to read time (one shared clock, one commit per drained batch) with the backward smear as a settled window — each completed bucket enters once, donates excess to the nearest earlier deficits once, locks for display when nothing later can refill it (per-sample recompute double-counted excess and read >20G on a 20G wire); timestamp machinery deleted (ts.go, SO_TIMESTAMPING, rx_filter=ALL check) after the audit confirmed the buckets were its sole consumer; testDriver ixgbe; RollBall mailbox hardened against orphaned-command completions (never sample status before a poll gap, value from the same block read, devad/reg echo required — a killed session's 7.60 read answered a PHY ID as 0x0006); full hardware pass: 20.00G flat both directions, zero errors, ECD 42m, SNR +7.4dB

system.go

@@ -754,7 +754,6 @@ func configureSystem(ifnames []string, ethertypes []uint16) []checkResult {
 			// queues have to be installed afterwards.
 			out = append(out, checkRings(fd, ifname, wantRxRing, wantTxRing))
 			out = append(out, checkCoalesce(fd, ifname, wantCoalesceUsecs, wantCoalesceUsecs))
-			out = append(out, checkTimestamping(fd, ifname))
 			out = append(out, checkFlowRules(fd, ifname, ethertypes))
 		}
 		return out