[ovs-dev,RFC,0/2] Ingress Scheduling

This patch set implements the 'preferential read' part of the feature of
ingress scheduling described at OvS 2017 Fall Conference
https://www.slideshare.net/LF_OpenvSwitch/lfovs17ingress-scheduling-82280320.

It allows configuration to specify an ingress priority for and entire
interface. This protects traffic on higher priority interfaces from loss and
latency as PMDs get overloaded.

Results so far a are very promising; For a uniform traffic distribution as
total offered load increases loss starts on the lowest priority port first and
the highest priority port last.

When using four physical ports with each port forwarded to one of the other
ports. The following packets loss is seen. The EMC was bypassed in this case
and a small delay loop was added to each packet to simulate more realistic per
packet processing cost of 1000cycles approx.

Port     dpdk_0  dpdk_1  dpdk_2  dpdk_3
Traffic
Dist.       25%     25%     25%     25%
Priority      0       1       2       3
n_rxq         8       8       8       8

Total
Load Kpps   Loss Rate Per Port (Kpps)
2110          0       0       0       0
2120          5       0       0       0
2920        676       0       0       0
2930        677       5       0       0
3510        854     411       0       0
3520        860     415       3       0
4390       1083     716     348       0
4400       1088     720     354       1


Even in the case where most traffic is on the priority port this remains the
case:

Port     dpdk_0  dpdk_1  dpdk_2  dpdk_3
Traffic
Dist.       10%     20%     30%     40%
Priority      0       1       2       3
n_rxq         8       8       8       8

Total
Load Kpps   Loss Rate Per Port (Kpps)
     2400     0       0       0       0
     2410     5       0       0       0
     2720   225       5       0       0
     2880   252     121       9       0
     3030   269     176      82       3
     4000   369     377     384     392
     5000   471     580     691     801

The latency characteristics of the traffic on the higher priority ports is also
protected.

Port     dpdk_0  dpdk_1  dpdk_2  dpdk_3
Traffic
Dist.       10%     20%     30%     40%
Priority      0       1       2       3
n_rxq         8       8       8       8

Total        dpdk0    dpdk1    dpdk2    dpdk3
Load Kpps
     2400      113      122      120      125
     2410    36117      571      577      560
     2720   323242    14424     3265     3235
     2880   391404    33508    10075     4600
     3030   412597    35450    17061     7965
     4000   414729    36070    17740    11106
     5000   416801    36445    18233    11653

Some General setup notes:
Fortville. (X710 DA4. firmware-version: 6.01 0x800034af 1.1747.0)
Intel(R) Xeon(R) CPU E5-2695 v3 @ 2.30GHz
One pmd
Port fwding port 0<->1, 2 <-> 3
Frame 64B, UDP 221 streams per port.
OvS base - 4c80644 http://github.com/istokes/ovs dpdk_merge_2_9. Added 600cycles approx pkt processing in order to bring per packet cost to ~1000 cycles.
DPDK v17.11.1

Billy O'Mahony (2):
  ingress scheduling: schema and docs
  ingress scheduling: Provide per interface ingress priority

 Documentation/howto/dpdk.rst    | 18 ++++++++++++
 include/openvswitch/ofp-parse.h |  3 ++
 lib/dpif-netdev.c               | 47 +++++++++++++++++++++---------
 lib/netdev-bsd.c                |  1 +
 lib/netdev-dpdk.c               | 64 +++++++++++++++++++++++++++++++++++++++--
 lib/netdev-dummy.c              |  1 +
 lib/netdev-linux.c              |  1 +
 lib/netdev-provider.h           | 11 ++++++-
 lib/netdev-vport.c              |  1 +
 lib/netdev.c                    | 23 +++++++++++++++
 lib/netdev.h                    |  2 ++
 vswitchd/bridge.c               |  2 ++
 vswitchd/vswitch.ovsschema      |  9 ++++--
 vswitchd/vswitch.xml            | 40 ++++++++++++++++++++++++++
 14 files changed, 205 insertions(+), 18 deletions(-)