linux-kernel - Re: [RFC PATCH 0/7] sched: cpufreq: Remove magic margins

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: <20230910211710.a367up7rstm2l7zr@airbuntu>
Date:   Sun, 10 Sep 2023 22:17:10 +0100
From:   Qais Yousef <qyousef@...alina.io>
To:     Peter Zijlstra <peterz@...radead.org>
Cc:     Ingo Molnar <mingo@...nel.org>,
        "Rafael J. Wysocki" <rafael@...nel.org>,
        Viresh Kumar <viresh.kumar@...aro.org>,
        Vincent Guittot <vincent.guittot@...aro.org>,
        Dietmar Eggemann <dietmar.eggemann@....com>,
        linux-kernel@...r.kernel.org, linux-pm@...r.kernel.org,
        Lukasz Luba <lukasz.luba@....com>
Subject: Re: [RFC PATCH 0/7] sched: cpufreq: Remove magic margins

On 09/08/23 14:33, Qais Yousef wrote:
> On 09/08/23 12:25, Peter Zijlstra wrote:
> > On Fri, Sep 08, 2023 at 01:17:25AM +0100, Qais Yousef wrote:
> > 
> > > Just to be clear, my main issue here with the current hardcoded values of the
> > > 'margins'. And the fact they go too fast is my main problem.
> > 
> > So I stripped the whole margin thing from my reply because I didn't want
> > to comment on that yet, but yes, I can see how those might be a problem,
> > and you're changing them into something dynamic, not just removing them.
> 
> The main difficulty is that if you try to apply those patches on their own, I'm
> sure you'll notice a difference. So if we were to take this alone and put them
> on linux-next; I expect a few regression reports for those who run with
> schedutil. Any ST oriented workload will not be happy. But if we compensate to
> reduce the regression, my problem will re-appear, just for a different reason.
> So whack-a-mole.

Sorry I just realized that the dynamic thing was about the margin, not the new
knob.

My answer above still holds to some extent. But yes, I meant to write that I'm
removing magic hardcoded numbers from the margins.


Cheers

--
Qais Yousef