Re: [PATCHSET v6 0/4] Split iowait into two states

[Rafael J. Wysocki]

On Wed, Sep 4, 2024 at 4:28 PM Peter Zijlstra <peterz@xxxxxxxxxxxxx> wrote:
>
> On Mon, Aug 19, 2024 at 09:39:45AM -0600, Jens Axboe wrote:
> > Hi,
> >
> > This is v6 of the patchset where the current in_iowait state is split
> > into two parts:
> >
> > 1) The "task is sleeping waiting on IO", and would like cpufreq goodness
> >    in terms of sleep and wakeup latencies.
> > 2) The above, and also accounted as such in the iowait stats.
> >
> > The current ->in_iowait covers both, this series splits it into two types
> > of state so that each can be controlled seperately.
>
> Yeah, but *WHY* !?!? I have some vague memories from last time around,
> but patches should really keep this information.
>
> > Patches 1..3 are prep patches, changing the type of
> > task_struct->nr_iowait and adding helpers to manipulate the iowait counts.
> >
> > Patch 4 does the actual splitting.
> >
> > This has been sitting for a while, would be nice to get this queued up
> > for 6.12. Comments welcome!
>
> Ufff, and all this because menu-governor does something insane :-(
>
> Rafael, why can't we simply remove this from menu?

Same reason as before: people use it and refuse to stop.

But this is mostly about the schedutil cpufreq governor that uses
iowait boosting.