Using the 1009 CCR and 1036 CCR routers, we're seeing very high CPU usage in processing simple queues when they use a parent. I'd like to say that I haven't seen this happen before in earlier versions of Router OS before the Bucket size was introduced, but in reading it looks like Bucket size was always used (just not editable). Maybe bucket size has nothing to do with it, not sure, looking for input.
Router 1 - 1009-7G-1C-1S+ with RouterOS 6.37.1:
Parent Queue manages 26 Child Queues with speeds ranging from 10mbps to 500mbps (half are 500mbps). If a lot of data is transferred or a speedtest is started, the CPU will increase to 50% plus for 500mbps speeds, and slightly lower on the lower speed packages. With some of our older setups, I don't recall seeing CPU rise so high when speedtesting is taking place.
If the child is removed from the parent, CPU rises minimally to 5% during a 500mbps speedtest.
Router 2 - 1036-8g-2s+ with RouterOS 6.37.3:
Parent Queue manages 280 Child Queues with speeds ranging from 100mbps to 1gbps (25% are 500mbps and up). Anytime a speedtest takes place on a connection with 500mbps and up speeds, CPU hits 100% and the speed tops out at about 300-500mbps. I removed all highspeed (500mbps+) queues from the Parent and CPU lowers drastically and speeds are near perfect when testing gigabit.
Testing on the 1036 with 280 Child Queues:
In Parent:
1000mbps: Uses 100% CPU on all cores and therefore it’s killing other people’s connections.
500mbps: Uses 100% CPU on all cores too.
100mbps: Uses only 10% CPU average. So 100mbps and lower works well.
Outside of Parent:
1000mbps: up to 30% CPU average over cores
500mbps: up to 25% CPU average over cores
100mbps: up to 10% CPU
*Keep in mind that there is roughly 10%+ usage already when performing these tests.