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Eric Dumazet authored
mlx4 RSS is limited to spread incoming packets to a power of two number of queues. An uniformly distibuted traffic would be split on queues 0 to N-1, N being a power of two, each queue having a 1/N weight. If number of RX queues is not a power of two, upper RX queues do not receive traffic. ethtool -x is lying, because it pretends some queues have higher weight. Before patch: lpaa24:~# ethtool -L eth1 rx 24 lpaa24:~# ethtool -x eth1 RX flow hash indirection table for eth1 with 24 RX ring(s): 0: 0 1 2 3 4 5 6 7 8: 8 9 10 11 12 13 14 15 16: 0 1 2 3 4 5 6 7 RSS hash key: e0:7c:3a:89:07:55:b6:58:69:cc:f4:e5:24:62:e3:25:88:6c:42:5b:d2:cb:9a:d2:e0:06:e1:dc:f9:09:a1:89:0f:a0:30:43:73:6f:0c:b6 If this information was correct, user space tools could expect queues 0 to 7 to receive twice more traffic than queues 8 to 15 After patch : lpaa24:~# ethtool -L eth1 rx 24 lpaa24:~# ethtool -x eth1 RX flow hash indirection table for eth1 with 24 RX ring(s): 0: 0 1 2 3 4 5 6 7 8: 8 9 10 11 12 13 14 15 RSS hash key: da:7b:09:60:f1:ac:67:b4:d0:72:d4:ec:a2:e5:80:0a:ad:50:22:1a:f8:f9:66:54:5f:22:45:c3:88:f4:57:82:c1:c1:90:ed:70:cb:40:ce lpaa24:~# ethtool -X eth1 equal 8 lpaa24:~# ethtool -x eth1 RX flow hash indirection table for eth1 with 24 RX ring(s): 0: 0 1 2 3 4 5 6 7 8: 0 1 2 3 4 5 6 7 RSS hash key: da:7b:09:60:f1:ac:67:b4:d0:72:d4:ec:a2:e5:80:0a:ad:50:22:1a:f8:f9:66:54:5f:22:45:c3:88:f4:57:82:c1:c1:90:ed:70:cb:40:ce Signed-off-by:
Eric Dumazet <edumazet@google.com> Reported-by:
Maciej Żenczykowski <maze@google.com> Cc: Eugenia Emantayev <eugenia@mellanox.com> Cc: Wei Wang <weiwan@google.com> Cc: Willem de Bruijn <willemb@google.com> Reviewed-by:
Tariq Toukan <tariqt@mellanox.com> Signed-off-by:
David S. Miller <davem@davemloft.net>
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