From: Dietmar Eggemann <dietmar.eggemann@arm.com>
To: Juri Lelli <juri.lelli@arm.com>, linux-kernel@vger.kernel.org
Cc: linux-pm@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
devicetree@vger.kernel.org, peterz@infradead.org,
vincent.guittot@linaro.org, robh+dt@kernel.org,
mark.rutland@arm.com, linux@arm.linux.org.uk,
sudeep.holla@arm.com, lorenzo.pieralisi@arm.com,
catalin.marinas@arm.com, will.deacon@arm.com,
morten.rasmussen@arm.com, broonie@kernel.org
Subject: Re: [PATCH v3 4/6] arm64: Enable dynamic CPU capacity initialization
Date: Mon, 8 Feb 2016 12:28:39 +0000 [thread overview]
Message-ID: <56B889F7.306@arm.com> (raw)
In-Reply-To: <1454500799-18451-5-git-send-email-juri.lelli@arm.com>
On 03/02/16 11:59, Juri Lelli wrote:
> Define arch_wants_init_cpu_capacity() to return true; so that
> cpufreq_init_cpu_capacity() can go ahead and profile CPU capacities
> at boot time.
[...]
>
> +bool arch_wants_init_cpu_capacity(void)
> +{
> + return true;
Isn't this a little bit too simple? Not every ARM/ARM64 platform is a
heterogeneous one.
You could add code to compare the cpu node 'compatible' properties
(required) and only return true if they differ, which would let you
detect uarch based heterogeneity.
In case of max. frequency based heterogeneity (clusters consisting of
same cpu types but running at different max. frequency), you're at the
mercy of cpu node 'clock-frequency' properties (optional).
We might argue that for these platforms, providing cpu node
'clock-frequency' properties is necessary.
The 'struct cpu_efficiency table_efficiency[]' based approach in ARM
already faces this problem.
> +}
> +
> static int __init get_cpu_for_node(struct device_node *node)
> {
> struct device_node *cpu_node;
>
next prev parent reply other threads:[~2016-02-08 12:28 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-02-03 11:59 [PATCH v3 0/6] CPUs capacity information for heterogeneous systems Juri Lelli
2016-02-03 11:59 ` [PATCH v3 1/6] ARM: initialize cpu_scale to its default Juri Lelli
2016-02-03 11:59 ` [PATCH v3 2/6] drivers/cpufreq: implement init_cpu_capacity_default() Juri Lelli
2016-02-03 21:04 ` Vincent Guittot
2016-02-04 9:36 ` Morten Rasmussen
2016-02-04 12:03 ` Vincent Guittot
2016-02-04 12:16 ` Juri Lelli
2016-02-04 12:35 ` Vincent Guittot
2016-02-04 14:13 ` Juri Lelli
2016-02-04 15:44 ` Vincent Guittot
2016-02-04 15:46 ` Vincent Guittot
2016-02-05 9:30 ` Juri Lelli
2016-02-09 15:54 ` Dietmar Eggemann
2016-02-10 14:25 ` Juri Lelli
2016-02-03 11:59 ` [PATCH v3 3/6] arm: Enable dynamic CPU capacity initialization Juri Lelli
2016-02-03 11:59 ` [PATCH v3 4/6] arm64: " Juri Lelli
2016-02-08 12:28 ` Dietmar Eggemann [this message]
2016-02-08 13:13 ` Mark Brown
2016-02-08 13:41 ` Dietmar Eggemann
2016-02-03 11:59 ` [PATCH v3 5/6] arm: add sysfs cpu_capacity attribute Juri Lelli
2016-02-03 11:59 ` [PATCH v3 6/6] arm64: " Juri Lelli
2016-02-05 17:19 ` Dietmar Eggemann
2016-02-05 17:49 ` Juri Lelli
2016-02-08 23:59 ` [PATCH v3 0/6] CPUs capacity information for heterogeneous systems Steve Muckle
2016-02-09 10:37 ` Juri Lelli
2016-02-09 17:30 ` Steve Muckle
2016-02-09 17:40 ` Juri Lelli
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=56B889F7.306@arm.com \
--to=dietmar.eggemann@arm.com \
--cc=broonie@kernel.org \
--cc=catalin.marinas@arm.com \
--cc=devicetree@vger.kernel.org \
--cc=juri.lelli@arm.com \
--cc=linux-arm-kernel@lists.infradead.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-pm@vger.kernel.org \
--cc=linux@arm.linux.org.uk \
--cc=lorenzo.pieralisi@arm.com \
--cc=mark.rutland@arm.com \
--cc=morten.rasmussen@arm.com \
--cc=peterz@infradead.org \
--cc=robh+dt@kernel.org \
--cc=sudeep.holla@arm.com \
--cc=vincent.guittot@linaro.org \
--cc=will.deacon@arm.com \
/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 read-only IMAP folder(s) and NNTP newsgroup(s).