[ovs-git] [openvswitch/ovs] 15ba07: netdev-dpdk: Fix Tx queue false sharing.

[Ilya Maximets]

  Branch: refs/heads/master
  Home:   https://github.com/openvswitch/ovs
  Commit: 15ba075d39b9cf1ba35c6938319ea6e1272ee43a
      https://github.com/openvswitch/ovs/commit/15ba075d39b9cf1ba35c6938319ea6e1272ee43a
  Author: Ilya Maximets <i.maximets at ovn.org>
  Date:   2019-10-22 (Tue, 22 Oct 2019)

  Changed paths:
    M lib/netdev-dpdk.c

  Log Message:
  -----------
  netdev-dpdk: Fix Tx queue false sharing.

'tx_q' array is allocated for each DPDK netdev.  'struct dpdk_tx_queue'
is 8 bytes long, so 8 tx queues are sharing the same cache line in
case of 64B cacheline size.  This causes 'false sharing' issue in
mutliqueue case because taking the spinlock implies write to memory
i.e. cache invalidation.

Signed-off-by: Ilya Maximets <i.maximets at ovn.org>
Acked-by: Eelco Chaudron <echaudro at redhat.com>