Re: [sched/fair] fcf0553db6: netperf.Throughput_Mbps -30.8% regression

From: Mel Gorman
Date: Sun Oct 04 2020 - 12:21:15 EST


On Sun, Oct 04, 2020 at 09:27:16PM +0800, kernel test robot wrote:
> Greeting,
>
> FYI, we noticed a -30.8% regression of netperf.Throughput_Mbps due to commit:
>
>
> commit: fcf0553db6f4c79387864f6e4ab4a891601f395e ("sched/fair: Remove meaningless imbalance calculation")
> https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git master
>

This commit was the start of a series that made large changes to load
balancing. The series was not bisect-safe and has since been reconciled
with the NUMA balancing. Any workload with a potential load balancing
problem has to be checked against the latest kernel to see if the problem
persists there. If it does, then tip/sched/core should be checked or
5.10-rc1 when it comes out as tip has a few more LB changes pending.

--
Mel Gorman
SUSE Labs