[ovs-git] [openvswitch/ovs] 7f67a5: dpif-netdev-perf: Fix double update of perf histog...

[istokes]

  Branch: refs/heads/branch-2.10
  Home:   https://github.com/openvswitch/ovs
  Commit: 7f67a5b5fb369049ceed0d754d0dad2f6adfdc88
      https://github.com/openvswitch/ovs/commit/7f67a5b5fb369049ceed0d754d0dad2f6adfdc88
  Author: Ilya Maximets <i.maximets at samsung.com>
  Date:   2019-03-19 (Tue, 19 Mar 2019)

  Changed paths:
    M lib/dpif-netdev-perf.c

  Log Message:
  -----------
  dpif-netdev-perf: Fix double update of perf histograms.

Real values of 'packets per batch' and 'cycles per upcall' already
added to histograms in 'dpif-netdev' on receive. Adding the averages
makes statistics wrong. We should not add to histograms values that
never really appeared.

For exmaple, in current code following situation is possible:

  pmd thread numa_id 0 core_id 5:
  ...
    Rx packets:                  83  (0 Kpps, 13873 cycles/pkt)
    ...
    - Upcalls:                    3  (  3.6 %, 248.6 us/upcall)

  Histograms
    packets/it      pkts/batch       upcalls/it     cycles/upcall
    1         83    1         166    1         3    ...
                                                    15848     2
                                                    19952     2
                                                    ...
                                                    50118     2

i.e. all the packets counted twice in 'pkts/batch' column and
all the upcalls counted twice in 'cycles/upcall' column.

CC: Jan Scheurich <jan.scheurich at ericsson.com>
Fixes: 79f368756ce8 ("dpif-netdev: Detailed performance stats for PMDs")
Signed-off-by: Ilya Maximets <i.maximets at samsung.com>
Signed-off-by: Ian Stokes <ian.stokes at intel.com>