[dpdk-stable] [PATCH v2 0/4] vhost: add missing barriers, move prefetching

[Maxime Coquelin]

This series adds missing read barriers after reading avail index
for split ring and desc flags for packed ring.

Also, it turns out that some descriptors prefetching are either
badly placed, or useless, last part of the series fixes that.

With the series applied, I get between 0 and 4% gain depending
on the benchmark (testpmd txonly/rxonly/io).

Thanks to Jason for reporting the missing read barriers.

Changes since v1:
=================
- Drop volatile removal patch (Ilya)
- Improve commit messages for RMB patches (Ilya)

Maxime Coquelin (4):
  vhost: enforce avail index and desc read ordering
  vhost: enforce desc flags and content read ordering
  vhost: prefetch descriptor after the read barrier
  vhost: remove useless prefetch for packed ring descriptor

 lib/librte_vhost/virtio_net.c | 27 ++++++++++++++++++++++-----
 1 file changed, 22 insertions(+), 5 deletions(-)

-- 
2.17.2