From: Ulf Hansson <ulf.hansson@linaro.org>
To: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Cc: Sudeep Holla <sudeep.holla@arm.com>,
Mark Rutland <mark.rutland@arm.com>,
Linux ARM <linux-arm-kernel@lists.infradead.org>,
"Rafael J . Wysocki" <rjw@rjwysocki.net>,
Daniel Lezcano <daniel.lezcano@linaro.org>,
"Raju P . L . S . S . S . N" <rplsssn@codeaurora.org>,
Amit Kucheria <amit.kucheria@linaro.org>,
Bjorn Andersson <bjorn.andersson@linaro.org>,
Stephen Boyd <sboyd@kernel.org>,
Niklas Cassel <niklas.cassel@linaro.org>,
Tony Lindgren <tony@atomide.com>,
Kevin Hilman <khilman@kernel.org>,
Lina Iyer <ilina@codeaurora.org>,
Viresh Kumar <viresh.kumar@linaro.org>,
Vincent Guittot <vincent.guittot@linaro.org>,
Geert Uytterhoeven <geert+renesas@glider.be>,
Souvik Chakravarty <souvik.chakravarty@arm.com>,
Linux PM <linux-pm@vger.kernel.org>,
linux-arm-msm <linux-arm-msm@vger.kernel.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 14/18] drivers: firmware: psci: Manage runtime PM in the idle path for CPUs
Date: Thu, 18 Jul 2019 12:35:07 +0200 [thread overview]
Message-ID: <CAPDyKFrJ75mo+s6GuUCTQ-nVv7C+9YJyTVmwuBZ2RKFOvOi3Nw@mail.gmail.com> (raw)
In-Reply-To: <20190716155317.GB32490@e121166-lin.cambridge.arm.com>
On Tue, 16 Jul 2019 at 17:53, Lorenzo Pieralisi
<lorenzo.pieralisi@arm.com> wrote:
>
> On Mon, May 13, 2019 at 09:22:56PM +0200, Ulf Hansson wrote:
> > When the hierarchical CPU topology layout is used in DT, let's allow the
> > CPU to be power managed through its PM domain, via deploying runtime PM
> > support.
> >
> > To know for which idle states runtime PM reference counting is needed,
> > let's store the index of deepest idle state for the CPU, in a per CPU
> > variable. This allows psci_cpu_suspend_enter() to compare this index with
> > the requested idle state index and then act accordingly.
>
> I do not see why a system with two CPU CPUidle states, say CPU retention
> and CPU shutdown, should not be calling runtime PM on CPU retention
> entry.
If the CPU idle governor did select the CPU retention for the CPU, it
was probably because the target residency for the CPU shutdown state
could not be met.
In this case, there is no point in allowing any other deeper idle
states for cluster/package/system, since those have even greater
residencies, hence calling runtime PM doesn't make sense.
>
> The question then is what cluster/package/system states
> are allowed for a given CPU idle state, to understand
> what idle states can be actually entered at any hierarchy
> level given the choice made for the CPU idle state.
>
> In the case above, a CPU entering retention state should prevent
> runtime PM selecting a cluster shutdown state; most likely firmware
> would demote the request to cluster retention but still, we should
> find a way to describe these dependencies.
See above.
[...]
Kind regards
Uffe
next prev parent reply other threads:[~2019-07-18 10:35 UTC|newest]
Thread overview: 68+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-05-13 19:22 [PATCH 00/18] ARM/ARM64: Support hierarchical CPU arrangement for PSCI Ulf Hansson
2019-05-13 19:22 ` [PATCH 01/18] dt: psci: Update DT bindings to support hierarchical PSCI states Ulf Hansson
2019-07-19 11:29 ` Lorenzo Pieralisi
2019-05-13 19:22 ` [PATCH 02/18] of: base: Add of_get_cpu_state_node() to get idle states for a CPU node Ulf Hansson
2019-05-13 19:22 ` [PATCH 03/18] cpuidle: dt: Support hierarchical CPU idle states Ulf Hansson
2019-05-13 19:22 ` [PATCH 04/18] ARM/ARM64: cpuidle: Let back-end init ops take the driver as input Ulf Hansson
2019-06-07 15:00 ` Sudeep Holla
2019-06-10 10:20 ` Ulf Hansson
2019-05-13 19:22 ` [PATCH 05/18] drivers: firmware: psci: Simplify state node parsing Ulf Hansson
2019-06-07 15:01 ` Sudeep Holla
2019-05-13 19:22 ` [PATCH 06/18] drivers: firmware: psci: Support hierarchical CPU idle states Ulf Hansson
2019-06-07 15:03 ` Sudeep Holla
2019-05-13 19:22 ` [PATCH 07/18] drivers: firmware: psci: Prepare to use OS initiated suspend mode Ulf Hansson
2019-06-07 15:17 ` Sudeep Holla
2019-06-10 10:21 ` Ulf Hansson
2019-06-10 10:42 ` Sudeep Holla
2019-07-16 14:53 ` Sudeep Holla
2019-05-13 19:22 ` [PATCH 08/18] drivers: firmware: psci: Prepare to support PM domains Ulf Hansson
2019-06-07 15:21 ` Sudeep Holla
2019-05-13 19:22 ` [PATCH 09/18] drivers: firmware: psci: Add support for PM domains using genpd Ulf Hansson
2019-06-07 15:27 ` Sudeep Holla
2019-06-10 10:21 ` Ulf Hansson
2019-06-10 10:59 ` Sudeep Holla
2019-07-16 15:05 ` Sudeep Holla
2019-07-18 11:04 ` Ulf Hansson
2019-07-18 13:19 ` Sudeep Holla
2019-07-18 17:57 ` Lina Iyer
2019-07-19 9:45 ` Sudeep Holla
2019-05-13 19:22 ` [PATCH 10/18] drivers: firmware: psci: Add hierarchical domain idle states converter Ulf Hansson
2019-07-09 15:31 ` Lorenzo Pieralisi
2019-07-16 8:45 ` Ulf Hansson
2019-07-16 14:51 ` Lorenzo Pieralisi
2019-07-18 11:43 ` Ulf Hansson
2019-07-18 13:36 ` Lorenzo Pieralisi
2019-05-13 19:22 ` [PATCH 11/18] drivers: firmware: psci: Introduce psci_dt_topology_init() Ulf Hansson
2019-05-13 19:22 ` [PATCH 12/18] drivers: firmware: psci: Add a helper to attach a CPU to its PM domain Ulf Hansson
2019-05-13 19:22 ` [PATCH 13/18] drivers: firmware: psci: Attach the CPU's device " Ulf Hansson
2019-05-13 19:22 ` [PATCH 14/18] drivers: firmware: psci: Manage runtime PM in the idle path for CPUs Ulf Hansson
2019-07-16 15:53 ` Lorenzo Pieralisi
2019-07-18 10:35 ` Ulf Hansson [this message]
2019-07-18 13:30 ` Lorenzo Pieralisi
2019-07-18 16:54 ` Ulf Hansson
2019-07-18 17:41 ` Lina Iyer
2019-07-18 21:49 ` Ulf Hansson
2019-07-19 10:02 ` Lorenzo Pieralisi
2019-05-13 19:22 ` [PATCH 15/18] drivers: firmware: psci: Support CPU hotplug for the hierarchical model Ulf Hansson
2019-06-07 15:31 ` Sudeep Holla
2019-06-10 10:21 ` Ulf Hansson
2019-06-10 11:02 ` Sudeep Holla
2019-05-13 19:22 ` [PATCH 16/18] arm64: kernel: Respect the hierarchical CPU topology in DT for PSCI Ulf Hansson
2019-05-13 19:22 ` [PATCH 17/18] arm64: dts: Convert to the hierarchical CPU topology layout for MSM8916 Ulf Hansson
2019-07-16 14:47 ` Sudeep Holla
2019-07-16 20:36 ` Lina Iyer
2019-07-17 17:18 ` Sudeep Holla
2019-05-13 19:23 ` [PATCH 18/18] arm64: dts: hikey: Convert to the hierarchical CPU topology layout Ulf Hansson
2019-07-16 14:47 ` Sudeep Holla
2019-07-18 10:48 ` Ulf Hansson
2019-07-18 13:11 ` Sudeep Holla
2019-05-14 8:08 ` [PATCH 00/18] ARM/ARM64: Support hierarchical CPU arrangement for PSCI Rafael J. Wysocki
2019-05-14 8:58 ` Ulf Hansson
2019-06-07 15:42 ` Sudeep Holla
2019-06-07 19:34 ` Bjorn Andersson
2019-06-10 10:32 ` Sudeep Holla
2019-06-10 15:54 ` Ulf Hansson
2019-06-10 17:16 ` Lorenzo Pieralisi
2019-06-10 18:57 ` Ulf Hansson
2019-06-18 11:56 ` Ulf Hansson
2019-06-07 11:19 ` Ulf Hansson
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=CAPDyKFrJ75mo+s6GuUCTQ-nVv7C+9YJyTVmwuBZ2RKFOvOi3Nw@mail.gmail.com \
--to=ulf.hansson@linaro.org \
--cc=amit.kucheria@linaro.org \
--cc=bjorn.andersson@linaro.org \
--cc=daniel.lezcano@linaro.org \
--cc=geert+renesas@glider.be \
--cc=ilina@codeaurora.org \
--cc=khilman@kernel.org \
--cc=linux-arm-kernel@lists.infradead.org \
--cc=linux-arm-msm@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-pm@vger.kernel.org \
--cc=lorenzo.pieralisi@arm.com \
--cc=mark.rutland@arm.com \
--cc=niklas.cassel@linaro.org \
--cc=rjw@rjwysocki.net \
--cc=rplsssn@codeaurora.org \
--cc=sboyd@kernel.org \
--cc=souvik.chakravarty@arm.com \
--cc=sudeep.holla@arm.com \
--cc=tony@atomide.com \
--cc=vincent.guittot@linaro.org \
--cc=viresh.kumar@linaro.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).