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

From: Peter Zijlstra
Date: Mon Oct 05 2020 - 02:51:40 EST


On Sun, Oct 04, 2020 at 05:21:08PM +0100, Mel Gorman wrote:
> 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.

What Mel said ;-)