> 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
> 

Hi Billy, thanks for your work on this feature.
I have one question here. Have you tasted heterogeneous configurations?
I mean situations where PMD thread polls different types of ports (NICs).
It's known that RX operations has different cost for different port types
(like virtual and physical) and also for different hardware NICs because
of different implementations of DPDK PMD drivers.

So, my concern: Is it possible that setting higher priority for a slower
port type (maybe vhost) may degrade overall performance of current PMD thread.
It'll be nice to have this kind of testing results.

Best regards, Ilya Maximets.

> 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(-)
> 
> -- 
> 2.7.4
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