[ovs-dev] [PATCH v4 5/7] dpif-netdev: Add group rxq scheduling assignment type.

David Marchand david.marchand at redhat.com
Mon Jul 12 08:13:39 UTC 2021


On Thu, Jul 8, 2021 at 3:54 PM Kevin Traynor <ktraynor at redhat.com> wrote:
>
> 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 a 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>

Acked-by: David Marchand <david.marchand at redhat.com>


-- 
David Marchand



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