From: Viresh Kumar <viresh.kumar@linaro.org>
To: Ionela Voinescu <ionela.voinescu@arm.com>
Cc: rjw@rjwysocki.net, sudeep.holla@arm.com,
linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] cpufreq,cppc: fix issue when hotplugging out policy->cpu
Date: Mon, 7 Sep 2020 11:41:54 +0530 [thread overview]
Message-ID: <20200907061154.iiyaq4m3vjtrlkp4@vireshk-i7> (raw)
In-Reply-To: <20200904094303.GA10031@arm.com>
On 04-09-20, 10:43, Ionela Voinescu wrote:
> Do you know why it was designed this way in the first place?
No.
> I assumed it was designed like this (per-cpu cppc_cpudata structures) to
> allow for the future addition of support for the HW_ALL CPPC coordination
> type. In that case you can still have PSD (dependency) domains but the
> desired performance controls would be per-cpu, with the coordination
> done in hardware/firmware. So, in the HW_ALL case you'd end up having
> different performance controls even for CPUs in the same policy.
> Currently the CPPC driver only supports SW_ANY which is the traditional
> cpufreq approach.
Then the person who would add that feature will take care of fixing the issues
then. We should make sure we handle the current use-case optimally. And a
per-cpu thing isn't working well for that.
--
viresh
next prev parent reply other threads:[~2020-09-07 6:12 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-03 11:19 [PATCH] cpufreq,cppc: fix issue when hotplugging out policy->cpu Ionela Voinescu
2020-09-04 5:06 ` Viresh Kumar
2020-09-04 9:43 ` Ionela Voinescu
2020-09-07 6:11 ` Viresh Kumar [this message]
2020-09-22 16:25 ` Ionela Voinescu
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