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Date:   Tue, 29 Jun 2021 10:25:03 +0530
From:   Viresh Kumar <viresh.kumar@linaro.org>
To:     Qian Cai <quic_qiancai@quicinc.com>
Cc:     Ionela Voinescu <ionela.voinescu@arm.com>,
        Vincent Guittot <vincent.guittot@linaro.org>,
        Rafael Wysocki <rjw@rjwysocki.net>,
        Ben Segall <bsegall@google.com>,
        Daniel Bristot de Oliveira <bristot@redhat.com>,
        Dietmar Eggemann <dietmar.eggemann@arm.com>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Ingo Molnar <mingo@redhat.com>,
        Juri Lelli <juri.lelli@redhat.com>,
        Mel Gorman <mgorman@suse.de>,
        Peter Zijlstra <peterz@infradead.org>,
        "Rafael J. Wysocki" <rafael@kernel.org>,
        Steven Rostedt <rostedt@goodmis.org>,
        Sudeep Holla <sudeep.holla@arm.com>,
        Will Deacon <will@kernel.org>,
        "open list:THERMAL" <linux-pm@vger.kernel.org>,
        ACPI Devel Maling List <linux-acpi@vger.kernel.org>,
        linux-kernel <linux-kernel@vger.kernel.org>,
        "Paul E. McKenney" <paulmck@kernel.org>,
        "Rafael J. Wysocki" <rafael.j.wysocki@intel.com>
Subject: Re: [PATCH V3 0/4] cpufreq: cppc: Add support for frequency
 invariance
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On 26-06-21, 09:41, Qian Cai wrote:
> Another date point is that set ACPI_CPPC_CPUFREQ_FIE=n fixed the issue that any CPU could run below the lowest freq.
> 
> schedutil:
> # cat /sys/devices/system/cpu/*/cpufreq/cpuinfo_cur_freq | sort | uniq  -c
>      80 1000000
>      78 1400000
>       1 2010000
>       1 2800000
> 
> userspace:
> # cat /sys/devices/system/cpu/*/cpufreq/cpuinfo_cur_freq | sort | uniq  -c
>     158 1000000
>       2 2000000

ACPI_CPPC_CPUFREQ_FIE can play a role with schedutil, but not with
userspace governor. Userspace doesn't use the values being updated by
ACPI_CPPC_CPUFREQ_FIE. So I think the CPUs may not have been idle,
just for some reason.

Also, now that you are able run on latest kernel (linux-next), it
would be better if we can talk in terms of that only going forward.
5.4 adds more to the already unstable results :)

-- 
viresh