From: Viresh Kumar <viresh.kumar@linaro.org>
To: Nicola Mazzucato <nicola.mazzucato@arm.com>
Cc: Ionela Voinescu <ionela.voinescu@arm.com>,
devicetree@vger.kernel.org, linux-pm@vger.kernel.org,
vireshk@kernel.org, daniel.lezcano@linaro.org, rjw@rjwysocki.net,
linux-kernel@vger.kernel.org, robh+dt@kernel.org,
sudeep.holla@arm.com, chris.redpath@arm.com,
morten.rasmussen@arm.com, linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH v2 2/2] [RFC] CPUFreq: Add support for cpu-perf-dependencies
Date: Fri, 9 Oct 2020 16:47:11 +0530 [thread overview]
Message-ID: <20201009111711.5sl7m24engcwiqii@vireshk-i7> (raw)
In-Reply-To: <42e3c8e9-cadc-d013-1e1f-fa06af4a45ff@arm.com>
On 09-10-20, 12:10, Nicola Mazzucato wrote:
> I thought about it and looked for other platforms' DT to see if can reuse
> existing opp information. Unfortunately I don't think it is optimal. The reason
> being that, because cpus have the same opp table it does not necessarily mean
> that they share a clock wire. It just tells us that they have the same
> capabilities (literally just tells us they have the same V/f op points).
No.
> Unless I am missing something?
Yes.
Here are the different scenarios which can happen.
- Two CPUs have separate OPP tables, even if they are exact copy of
each other, these CPUs don't share a clock line, but just v/f points
as you said.
- Two CPUs use the same OPP table, i.e. both point to it, but
"opp-shared" property is missing. This is same as above case. They
just share the v/f points and this is the preferred way instead of
duplicate OPP tables.
- Case two with "opp-shared" property present in the OPP table. The
CPUs share clock-lines.
And this is exactly how we find out today if CPUs share a policy or
not.
--
viresh
WARNING: multiple messages have this Message-ID (diff)
From: Viresh Kumar <viresh.kumar@linaro.org>
To: Nicola Mazzucato <nicola.mazzucato@arm.com>
Cc: devicetree@vger.kernel.org, linux-pm@vger.kernel.org,
vireshk@kernel.org, daniel.lezcano@linaro.org, rjw@rjwysocki.net,
linux-kernel@vger.kernel.org, robh+dt@kernel.org,
sudeep.holla@arm.com, chris.redpath@arm.com,
Ionela Voinescu <ionela.voinescu@arm.com>,
morten.rasmussen@arm.com, linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH v2 2/2] [RFC] CPUFreq: Add support for cpu-perf-dependencies
Date: Fri, 9 Oct 2020 16:47:11 +0530 [thread overview]
Message-ID: <20201009111711.5sl7m24engcwiqii@vireshk-i7> (raw)
In-Reply-To: <42e3c8e9-cadc-d013-1e1f-fa06af4a45ff@arm.com>
On 09-10-20, 12:10, Nicola Mazzucato wrote:
> I thought about it and looked for other platforms' DT to see if can reuse
> existing opp information. Unfortunately I don't think it is optimal. The reason
> being that, because cpus have the same opp table it does not necessarily mean
> that they share a clock wire. It just tells us that they have the same
> capabilities (literally just tells us they have the same V/f op points).
No.
> Unless I am missing something?
Yes.
Here are the different scenarios which can happen.
- Two CPUs have separate OPP tables, even if they are exact copy of
each other, these CPUs don't share a clock line, but just v/f points
as you said.
- Two CPUs use the same OPP table, i.e. both point to it, but
"opp-shared" property is missing. This is same as above case. They
just share the v/f points and this is the preferred way instead of
duplicate OPP tables.
- Case two with "opp-shared" property present in the OPP table. The
CPUs share clock-lines.
And this is exactly how we find out today if CPUs share a policy or
not.
--
viresh
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next prev parent reply other threads:[~2020-10-09 11:17 UTC|newest]
Thread overview: 88+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-24 9:53 [PATCH v2 0/2] CPUFreq: Add support for cpu performance dependencies Nicola Mazzucato
2020-09-24 9:53 ` Nicola Mazzucato
2020-09-24 9:53 ` [PATCH v2 1/2] dt-bindings: arm: Add devicetree binding for cpu-performance-dependencies Nicola Mazzucato
2020-09-24 9:53 ` Nicola Mazzucato
2020-10-08 13:42 ` Ionela Voinescu
2020-10-08 13:42 ` Ionela Voinescu
2020-09-24 9:53 ` [PATCH v2 2/2] [RFC] CPUFreq: Add support for cpu-perf-dependencies Nicola Mazzucato
2020-09-24 9:53 ` Nicola Mazzucato
2020-10-06 7:19 ` Viresh Kumar
2020-10-06 7:19 ` Viresh Kumar
2020-10-07 12:58 ` Nicola Mazzucato
2020-10-07 12:58 ` Nicola Mazzucato
2020-10-08 11:02 ` Viresh Kumar
2020-10-08 11:02 ` Viresh Kumar
2020-10-08 15:03 ` Ionela Voinescu
2020-10-08 15:03 ` Ionela Voinescu
2020-10-08 15:57 ` Rafael J. Wysocki
2020-10-08 15:57 ` Rafael J. Wysocki
2020-10-08 17:08 ` Ionela Voinescu
2020-10-08 17:08 ` Ionela Voinescu
2020-10-12 16:06 ` Sudeep Holla
2020-10-12 16:06 ` Sudeep Holla
2020-10-08 16:00 ` Nicola Mazzucato
2020-10-08 16:00 ` Nicola Mazzucato
2020-10-09 5:39 ` Viresh Kumar
2020-10-09 5:39 ` Viresh Kumar
2020-10-09 11:10 ` Nicola Mazzucato
2020-10-09 11:10 ` Nicola Mazzucato
2020-10-09 11:17 ` Viresh Kumar [this message]
2020-10-09 11:17 ` Viresh Kumar
2020-10-09 14:01 ` Rob Herring
2020-10-09 14:01 ` Rob Herring
2020-10-09 15:28 ` Nicola Mazzucato
2020-10-09 15:28 ` Nicola Mazzucato
2020-10-12 4:19 ` Viresh Kumar
2020-10-12 4:19 ` Viresh Kumar
2020-10-12 10:22 ` Lukasz Luba
2020-10-12 10:22 ` Lukasz Luba
2020-10-12 10:50 ` Rafael J. Wysocki
2020-10-12 10:50 ` Rafael J. Wysocki
2020-10-12 11:05 ` Lukasz Luba
2020-10-12 11:05 ` Lukasz Luba
2020-10-12 10:59 ` Ionela Voinescu
2020-10-12 10:59 ` Ionela Voinescu
2020-10-12 13:48 ` Lukasz Luba
2020-10-12 13:48 ` Lukasz Luba
2020-10-12 16:30 ` Ionela Voinescu
2020-10-12 16:30 ` Ionela Voinescu
2020-10-12 18:19 ` Lukasz Luba
2020-10-12 18:19 ` Lukasz Luba
2020-10-12 22:01 ` Ionela Voinescu
2020-10-12 22:01 ` Ionela Voinescu
2020-10-13 11:53 ` Rafael J. Wysocki
2020-10-13 11:53 ` Rafael J. Wysocki
2020-10-13 12:39 ` Ionela Voinescu
2020-10-13 12:39 ` Ionela Voinescu
2020-10-15 15:56 ` Rafael J. Wysocki
2020-10-15 15:56 ` Rafael J. Wysocki
2020-10-15 18:38 ` Ionela Voinescu
2020-10-15 18:38 ` Ionela Voinescu
2020-10-12 13:59 ` Rob Herring
2020-10-12 13:59 ` Rob Herring
2020-10-12 16:02 ` Sudeep Holla
2020-10-12 16:02 ` Sudeep Holla
2020-10-12 15:54 ` Sudeep Holla
2020-10-12 15:54 ` Sudeep Holla
2020-10-12 15:49 ` Sudeep Holla
2020-10-12 15:49 ` Sudeep Holla
2020-10-12 16:52 ` Ionela Voinescu
2020-10-12 16:52 ` Ionela Voinescu
2020-10-12 17:18 ` Lukasz Luba
2020-10-12 17:18 ` Lukasz Luba
2020-10-14 4:25 ` Viresh Kumar
2020-10-14 4:25 ` Viresh Kumar
2020-10-14 9:11 ` Lukasz Luba
2020-10-14 9:11 ` Lukasz Luba
2020-10-19 8:50 ` Nicola Mazzucato
2020-10-19 8:50 ` Nicola Mazzucato
2020-10-19 9:46 ` Viresh Kumar
2020-10-19 9:46 ` Viresh Kumar
2020-10-19 13:36 ` Nicola Mazzucato
2020-10-19 13:36 ` Nicola Mazzucato
2020-10-20 10:48 ` Viresh Kumar
2020-10-20 10:48 ` Viresh Kumar
2020-10-13 13:53 ` Lukasz Luba
2020-10-13 13:53 ` Lukasz Luba
2020-10-14 4:20 ` Viresh Kumar
2020-10-14 4:20 ` Viresh Kumar
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