Hello Kevin, On Fri, Mar 5, 2021 at 10:37 PM Kevin Traynor <[email protected]> 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 > triggered. > > 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: > > https://docs.openvswitch.org/en/latest/topics/dpdk/pmd/?highlight=rebalance#automatic-assignment-of-port-rx-queue-to-pmd-threads-experimental > > 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 > etc. > > - Unit tests > Some patches here: > > http://patchwork.ozlabs.org/project/openvswitch/patch/[email protected]/ > > - 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 > regardless > i.e. > https://mail.openvswitch.org/pipermail/ovs-dev/2021-February/380386.html > > - Review/Improve operation documentation > > - Further testing > > Thoughts? > > I was able to evaluate ALB with 2.15 release, by using a traffic generator[1] 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[1] to evaluate ALB with bidirectional traffic. If you have any scenario or traffic pattern in mind, happy to adapt the traffic generator and evaluate ALB with those too. [1] https://github.com/yogananth-subramanian/multiqueue_traffic_gen > thanks, > Kevin. > > _______________________________________________ > dev mailing list > [email protected] > https://mail.openvswitch.org/mailman/listinfo/ovs-dev > -- Kind Regards yogananth subramanian _______________________________________________ dev mailing list [email protected] https://mail.openvswitch.org/mailman/listinfo/ovs-dev
