linux-kernel - Re: [PATCH] PM:EM: fix wrong utilization estimation in em_cpu

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Date: Thu, 4 Apr 2024 21:05:12 +0200
From: "Rafael J. Wysocki" <rafael@...nel.org>
To: Lukasz Luba <lukasz.luba@....com>, Vincent Guittot <vincent.guittot@...aro.org>
Cc: rui.zhang@...el.com, amit.kucheria@...durent.com, amit.kachhap@...il.com, 
	daniel.lezcano@...aro.org, viresh.kumar@...aro.org, len.brown@...el.com, 
	pavel@....cz, mhiramat@...nel.org, qyousef@...alina.io, wvw@...gle.com, 
	xuewen.yan94@...il.com, rafael@...nel.org, linux-kernel@...r.kernel.org, 
	linux-pm@...r.kernel.org, dietmar.eggemann@....com
Subject: Re: [PATCH] PM:EM: fix wrong utilization estimation in em_cpu_energy()

On Thu, Apr 4, 2024 at 1:05 PM Lukasz Luba <lukasz.luba@....com> wrote:
>
> Hi Vincent,
>
> On 4/4/24 11:42, Vincent Guittot wrote:
> > Commit 1b600da51073 ("PM: EM: Optimize em_cpu_energy() and remove division")
> > has added back map_util_perf() in em_cpu_energy() computation which has
> > been removed with the rework of scheduler/cpufreq interface.
> > This is wrong because sugov_effective_cpu_perf() already takes care of
> > mapping the utilization to a performance level.
> >
> > Fixes: 1b600da51073 ("PM: EM: Optimize em_cpu_energy() and remove division")
> > Signed-off-by: Vincent Guittot <vincent.guittot@...aro.org>
> > ---
> >   include/linux/energy_model.h | 1 -
> >   1 file changed, 1 deletion(-)
> >
> > diff --git a/include/linux/energy_model.h b/include/linux/energy_model.h
> > index 770755df852f..70cd7258cd29 100644
> > --- a/include/linux/energy_model.h
> > +++ b/include/linux/energy_model.h
> > @@ -245,7 +245,6 @@ static inline unsigned long em_cpu_energy(struct em_perf_domain *pd,
> >        * max utilization to the allowed CPU capacity before calculating
> >        * effective performance.
> >        */
> > -     max_util = map_util_perf(max_util);
> >       max_util = min(max_util, allowed_cpu_cap);
> >
> >       /*
>
> LGTM. It was developed in parallel IIRC and that change which removes
> the extra margin to the util was lost from my radar. I can see it
> landed first.
>
> Reviewed-by: Lukasz Luba <lukasz.luba@....com>

Applied as 6.9-rc material, thanks!