[ovs-dev] [PATCH v4 0/6] OVS-DPDK rxq to pmd assignment improvements.

[Jan Scheurich]

Hi Kevin,

> @Jan, can you comment on length of time to take into consideration when
> re-balancing - when we talked before you had some views on it. I will post
> a v5 when we get consensus around that.

When we originally discussed time scale, I was thinking about the automatic rebalancing of rx queues in the event of sudden PMD congestion. In that case a reaction time of 1 second seemed appropriate to minimize the loss of packets and to base the new distribution on the actual load rather than some outdated long-term average.

Now that we are looking at a manual procedure (or a procedure triggered at reconfiguration time), it would appear more suitable to look at an interval of, say, 60 seconds. I wouldn't go beyond that. 

If the overall load level is not too high, it doesn’t matter for re-balancing if the queue load levels are not very accurate (we have been living with assuming equal load levels in the past.) But if I manually trigger a re-balance because one PMD is (close to being) congested, I want the current queue load used for the procedure. Otherwise  I risk that the new queue distribution is worse than before.

In the future, when we tackle the automatic rebalancing in case of overload of individual PMDs, we can reduce the measurement time as needed.

BR, Jan