Commits
Willem de Bruijn committed 9954729bc38
packet: rollover only to socket with headroom
Only migrate flows to sockets that have sufficient headroom, where
sufficient is defined as having at least 25% empty space.
The kernel has three different buffer types: a regular socket, a ring
with frames (TPACKET_V[12]) or a ring with blocks (TPACKET_V3). The
latter two do not expose a read pointer to the kernel, so headroom is
not computed easily. All three needs a different implementation to
estimate free space.
Tested:
Ran bench_rollover for 10 sec with 1.5 Mpps of single flow input.
bench_rollover has as many sockets as there are NIC receive queues
in the system. Each socket is owned by a process that is pinned to
one of the receive cpus. RFS is disabled. RPS is enabled with an
identity mapping (cpu x -> cpu x), to count drops with softnettop.
lpbb5:/export/hda3/willemb# ./bench_rollover -r -l 1000 -s
Press [Enter] to exit
cpu rx rx.k drop.k rollover r.huge r.failed
0 16 16 0 0 0 0
1 21 21 0 0 0 0
2 5227502 5227502 0 0 0 0
3 18 18 0 0 0 0
4 6083289 6083289 0 5227496 0 0
5 22 22 0 0 0 0
6 21 21 0 0 0 0
7 9 9 0 0 0 0
Signed-off-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>