[ovs-dev] PMD auto load balance experimental tag
sy.ananth at gmail.com
Thu Mar 18 21:04:03 UTC 2021
On Fri, Mar 5, 2021 at 10:37 PM Kevin Traynor <ktraynor at redhat.com> wrote:
> Hi All,
> PMD auto load balance (ALB) is an experimental feature since OVS 2.11.
> In short, RxQs are reassigned to PMDs based on load during a reconfig.
> However, there might not be a reconfig for a long time so ALB runs
> periodically and checks PMD thread load and the load variance between
> PMD threads. If load is high and it's estimated that it will be improved
> by a certain amount after reassigning RxQs to PMDs, a reassignment is
> ALB calls the reassignment code similar to if there was a reconfig or if
> the rebalance command is used. There are some ideas for how to improve
> RxQ to PMD assignments in general, but that's a slightly different topic
> and can be a later optimization if needed.
> ALB is documented more here:
> I would like to progress it so the experimental tag on ALB can be
> removed. There are a few things I think are needed:
> - Need to restructure the code so that ALB reassignment dry run uses the
> same code path as the reassignment code it will call
> - ALB operation should be understandable through logs and stats
> e.g. Should be able to confirm setting state/parameters in logs and see
> if ALB is taking some action. Should be able to get more debug if needed
> - Unit tests
> Some patches here:
> - Iron out if the current ALB enable/disable user interface logging
> based partly min resource requirements is right or we want to it to run
> - Review/Improve operation documentation
> - Further testing
> I was able to evaluate ALB with 2.15 release, by using a traffic
generator that is able to deterministically load only the desired rxqs
associated with a PMD, hence I was able to deterministically evaluate ALB
for different values of pmd-auto-lb-load-threshold and n_rxq.
Currently working on enhancing traffic generator to evaluate ALB with
If you have any scenario or traffic pattern in mind, happy to adapt the
traffic generator and evaluate ALB with those too.
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