linux-kernel - Re: [PATCH v6 11/16] sched/fair: Add uclamp support to energy

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: Windows password security audit tool. GUI, reports in PDF.

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

Message-ID: <20190122151404.5rtosic6puixado3@queper01-lin>
Date:   Tue, 22 Jan 2019 15:14:06 +0000
From:   Quentin Perret <quentin.perret@....com>
To:     Patrick Bellasi <patrick.bellasi@....com>
Cc:     linux-kernel@...r.kernel.org, linux-pm@...r.kernel.org,
        linux-api@...r.kernel.org, Ingo Molnar <mingo@...hat.com>,
        Peter Zijlstra <peterz@...radead.org>,
        Tejun Heo <tj@...nel.org>,
        "Rafael J . Wysocki" <rafael.j.wysocki@...el.com>,
        Vincent Guittot <vincent.guittot@...aro.org>,
        Viresh Kumar <viresh.kumar@...aro.org>,
        Paul Turner <pjt@...gle.com>,
        Dietmar Eggemann <dietmar.eggemann@....com>,
        Morten Rasmussen <morten.rasmussen@....com>,
        Juri Lelli <juri.lelli@...hat.com>,
        Todd Kjos <tkjos@...gle.com>,
        Joel Fernandes <joelaf@...gle.com>,
        Steve Muckle <smuckle@...gle.com>,
        Suren Baghdasaryan <surenb@...gle.com>
Subject: Re: [PATCH v6 11/16] sched/fair: Add uclamp support to
 energy_compute()

On Tuesday 22 Jan 2019 at 15:01:37 (+0000), Patrick Bellasi wrote:
> > I'm not saying it's useful, I'm saying userspace can decide to do that
> > if it thinks it is a good idea. The default should be min_cap = 1024 for
> > RT, no questions. But you _can_ change it at runtime if you want to.
> > That's my point. And doing that basically provides the same behaviour as
> > what we have right now in terms of EAS calculation (but it changes the
> > freq selection obviously) which is why I'm not fundamentally opposed to
> > your patch.
> 
> Well, I think it's tricky to say whether the current or new approach
> is better... it probably depends on the use-case.

Agreed.

> > So in short, I'm fine with the behavioural change, but please at least
> > mention it somewhere :-)
> 
> Anyway... agree, it's just that to add some documentation I need to
> get what you are pointing out ;)
> 
> Will come up with some additional text to be added to the changelog

Sounds good.

> Maybe we can add a more detailed explanation of the different
> behaviors you can get in the EAS documentation which is coming to
> mainline ?

Yeah, if you feel like it, I guess that won't hurt :-)

Thanks,
Quentin