UDP busy polling is restricted to connected UDP sockets.
This is because sk_busy_loop() only takes care of one NAPI context.
There are cases where it could be extended.
1) Some hosts receive traffic on a single NIC, with one RX queue.
2) Some applications use SO_REUSEPORT and associated BPF filter
to split the incoming traffic on one UDP socket per RX
queue/thread/cpu
3) Some UDP sockets are used to send/receive traffic for one flow, but
they do not bother with connect()
This patch records the napi_id of first received skb, giving more
reach to busy polling.
Tested:
lpaa23:~# echo 70 >/proc/sys/net/core/busy_read
lpaa24:~# echo 70 >/proc/sys/net/core/busy_read
lpaa23:~# for f in `seq 1 10`; do ./super_netperf 1 -H lpaa24 -t UDP_RR -l 5; done
Before patch :
27867 28870 37324 41060 41215
36764 36838 44455 41282 43843
After patch :
73920 73213 70147 74845 71697
68315 68028 75219 70082 73707
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Willem de Bruijn <willemb@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
e68b6e50fa