[ovs-dev] [PATCH v2 5/7] dpif-netdev: Add group rxq scheduling assignment type.

[Pai G, Sunil]

Hi Kevin , 


> -----Original Message-----
> From: Kevin Traynor <ktraynor at redhat.com>
> Sent: Friday, July 2, 2021 4:55 AM
> To: dev at openvswitch.org
> Cc: david.marchand at redhat.com; Pai G, Sunil <sunil.pai.g at intel.com>;
> cfontain at redhat.com; Kevin Traynor <ktraynor at redhat.com>
> Subject: [PATCH v2 5/7] dpif-netdev: Add group rxq scheduling assignment
> type.
> 
> Add an rxq scheduling option that allows rxqs to be grouped on a pmd based
> purely on their load.
> 
> The current default 'cycles' assignment sorts rxqs by measured processing
> load and then assigns them to a list of round robin PMDs.
> This helps to keep the rxqs that require most processing on different cores
> but as it selects the PMDs in round robin order, it equally distributes rxqs to
> PMDs.
> 
> 'cycles' assignment has the advantage in that it separates the most loaded
> rxqs from being on the same core but maintains the rxqs being spread across
> a broad range of PMDs to mitigate against changes to traffic pattern.
> 
> 'cycles' assignment has the disadvantage that in order to make the trade off
> between optimising for current traffic load and mitigating against future
> changes, it tries to assign and equal amount of rxqs per PMD in a round robin
> manner and this can lead to less than optimal balance of the processing load.
> 
> Now that PMD auto load balance can help mitigate with future changes in
> traffic patterns, a 'group' assignment can be used to assign rxqs based on
> their measured cycles and the estimated running total of the PMDs.
> 
> In this case, there is no restriction about keeping equal number of rxqs per
> PMD as it is purely load based.
> 
> This means that one PMD may have a group of low load rxqs assigned to it
> while another PMD has one high load rxq assigned to it, as that is the best
> balance of their measured loads across the PMDs.
> 
> Signed-off-by: Kevin Traynor <ktraynor at redhat.com>
> ---
>  Documentation/topics/dpdk/pmd.rst | 26 +++++++++++++++++++
>  NEWS                              |  2 ++
>  lib/dpif-netdev.c                 | 42 +++++++++++++++++++++++++++++--
>  tests/pmd.at                      | 19 ++++++++++++--
>  vswitchd/vswitch.xml              |  5 +++-
>  5 files changed, 89 insertions(+), 5 deletions(-)
> 

Thanks for adding the test cases.
Patch LGTM with common *get_lowest* function.
Will ack once GHA is all green.

Thanks and regards,
Sunil