Re: SD_LOAD_BALANCE

[Julia Lawall <julia.lawall@inria.fr>]

On Mon, 12 Oct 2020, Peter Zijlstra wrote:

> On Sat, Oct 10, 2020 at 06:14:23PM +0200, Julia Lawall wrote:
> > Prior to v5.8 on my machine this was a rare event, because there were not
> > many of these background processes.  But in v5.8, the default governor for
> > Intel machines without the HWP feature was changed from intel_pstate to
> > intel_cpufreq.  The use of intel_cpufreq triggers very frequent kworkers on
> > all cores, which makes it much more likely that cores that are currently
> > idle, and are overall not at all overloaded, will have a higher load
> > average even with the waking thread deducted, than the core managing the
> > wakeup of the threads.
>
> Rafael, any idea what those kworkers are for, and can we get rid of
> them?

They execute the function intel_cpufreq_target defined in
drivers/cpufreq/intel_pstate.c

julia