[PATCH v3 net-next 0/2] rx busy polling support for virtio-net

[Jason Wang <jasowang@redhat.com>]

Hi all:

This series introduces the support for rx busy polling support. This
was useful for reduing the latency for a kvm guest. Instead of
introducing new states and spinlocks, this series re-uses NAPI state
to synchonrize between NAPI and busy polling. This grealy simplified
the codes and reduce the overheads of spinlocks for normal NAPI fast
path.

Test was done between a kvm guest and an external host. Two hosts were
connected through 40gb mlx4 cards. With both busy_poll and  busy_read
are set to 50 in guest, 1 byte netperf tcp_rr shows 127% improvement:
transaction rate was increased from 8353.33 to 18966.87.

Changes from V2:
- Avoid introducing new states and spinlocks by reusuing the NAPI
  state
- Fix the budget calculation in virtnet_poll()
- Drop patch 1/3 from V2 since it was useless

Changes from V1:
- split the patch info smaller ones
- add more details about test setup/configuration

Jason Wang (2):
  virtio-net: introduce virtnet_receive()
  virtio-net: rx busy polling support

 drivers/net/virtio_net.c | 67 +++++++++++++++++++++++++++++++++++++++++++-----
 1 file changed, 61 insertions(+), 6 deletions(-)

-- 
1.8.3.1