linux-kernel - Re: cpufreq: intel_pstate: map utilization into the pstate range

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] [day] [month] [year] [list]

Message-ID: <alpine.DEB.2.22.394.2201062258090.3098@hadrien>
Date:   Thu, 6 Jan 2022 22:58:31 +0100 (CET)
From:   Julia Lawall <julia.lawall@...ia.fr>
To:     srinivas pandruvada <srinivas.pandruvada@...ux.intel.com>
cc:     Francisco Jerez <currojerez@...eup.net>,
        "Rafael J. Wysocki" <rafael@...nel.org>,
        Len Brown <lenb@...nel.org>,
        Viresh Kumar <viresh.kumar@...aro.org>,
        Linux PM <linux-pm@...r.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        Ingo Molnar <mingo@...hat.com>,
        Peter Zijlstra <peterz@...radead.org>,
        Juri Lelli <juri.lelli@...hat.com>,
        Vincent Guittot <vincent.guittot@...aro.org>
Subject: Re: cpufreq: intel_pstate: map utilization into the pstate range



On Thu, 6 Jan 2022, srinivas pandruvada wrote:

> On Thu, 2022-01-06 at 21:43 +0100, Julia Lawall wrote:
> > > > All the turbostat output and graphs I have sent recently were
> > > > just
> > > > for
> > > > continuous spinning:
> > > >
> > > > for(;;);
> > > >
> > > > Now I am trying running for the percentage of the time
> > > > corresponding
> > > > to
> > > > 10 / P for pstate P (ie 0.5 of the time for pstate 20), and then
> > > > sleeping,
> > > > to see whether one can just add the sleeping power consumption of
> > > > the
> > > > machine to compute the efficiency as Rafael suggested.
> > > >
> > > Before doing comparison try freezing uncore.
> > >
> > > wrmsr -a 0x620 0x0808
> > >
> > > to Freeze uncore at 800MHz. Any other value is fine.
> >
> > Thanks for the suggestion.  What is the impact of this?
> Uncore scales based on its own heuristics based in P-state change and
> works in package scope. So to actually see the effect of P-state change
> on energy you can remove variability of uncore power.

OK, thanks.  I will try both options.

julia