Need further testing, this is initial review.
My test setup was to have a single host with an 82574L connected to a switch on a seperate network connected to my test host.
[netboot/nfs test machine](83574L) <-> [gig-e switch] <-> [lab server](realtek gig-e or intel gig-e, 82574L).
From the lab server I run a netperf server listening on port 10001 (/usr/local/bin/netserver -D -p 10001)
From the test machine, running netperf and checking the value of netstat -s | grep "duplicate ack" will show result in ever increasing values. In this scenario, this should not happen. Even with the patches contained in this ticket or running without EM_MULTIQUEUE enabled, duplicate acks increase.
Example test output:
# netperf -H 192.168.100.1 -n4 -p10001 -l600 -- -s64K ; netstat -s | grep "duplicate ack"
MIGRATED TCP STREAM TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to 192.168.100.1 () port 0 AF_INET : histogram : interval : dirty data : demo
Recv Send Send
Socket Socket Message Elapsed
Size Size Size Time Throughput
bytes bytes bytes secs. 10^6bits/sec
65536 65536 65536 600.08 835.92
10202 duplicate acks