linux-kernel - Re: Fwd: Intel hybrid CPU scheduler always prefers E cores

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Date:   Wed, 29 Nov 2023 00:17:47 +0100 (CET)
From:   Ramses <ramses@...l-founded.dev>
To:     Tim Chen <tim.c.chen@...ux.intel.com>
Cc:     Bagas Sanjaya <bagasdotme@...il.com>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        Linux Regressions <regressions@...ts.linux.dev>,
        Linux Power Management <linux-pm@...r.kernel.org>,
        "Rafael J. Wysocki" <rafael@...nel.org>,
        Viresh Kumar <viresh.kumar@...aro.org>,
        Ingo Molnar <mingo@...hat.com>,
        Peter Zijlstra <peterz@...radead.org>,
        Juri Lelli <juri.lelli@...hat.com>,
        Vincent Guittot <vincent.guittot@...aro.org>,
        Yu Chen <yu.c.chen@...el.com>,
        Srinivas Pandruvada <srinivas.pandruvada@...ux.intel.com>
Subject: Re: Fwd: Intel hybrid CPU scheduler always prefers E cores

Nov 29, 2023, 00:10 by tim.c.chen@...ux.intel.com:

> On Tue, 2023-11-28 at 23:33 +0100, Ramses wrote:
>
>> I applied the patch on top of 6.6.2, but unfortunately I see more or less the same behaviour as before, with single-threaded CPU-bound tasks running almost exclusively on E cores.
>>
>> Ramses
>>
>
> I suspect that you may have other issues. I wonder if CPU priorities are getting
> assigned properly on your system.
>
> Saw in the original bugzilla 
> https://bugzilla.kernel.org/show_bug.cgi?id=218195
> that you don't see /proc/sys/kernel/sched_itmt_enabled which
> may be a symptom of such a problem.
>
> +Srinivas, is there something Ramses can do to help
> find out if there are issues with cppc?
>
> Tim
>
Yeah I'm getting the impression that something is going wrong on my system. AFAIU, itmt is supposed to be auto-detected and doesn't require additional config?

I have the intel ME disabled on my CPU (it came like that from the OEM), I don't know if that can have an effect?

Let me know if there's any additional info that I can provide.

Ramses