From: Sudeep Holla <sudeep.holla@arm.com>
To: Linus Walleij <linus.walleij@linaro.org>
Cc: "Rafael J . Wysocki" <rafael@kernel.org>,
Viresh Kumar <viresh.kumar@linaro.org>,
linux-pm@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
Arnd Bergmann <arnd@arndb.de>,
Russell King <linux@armlinux.org.uk>,
Sudeep Holla <sudeep.holla@arm.com>,
Vincent Guittot <vincent.guittot@linaro.org>
Subject: Re: [PATCH] cpufreq: Select schedutil when using big.LITTLE
Date: Thu, 2 Apr 2020 10:14:55 +0100 [thread overview]
Message-ID: <20200402091446.GA19366@bogus> (raw)
In-Reply-To: <20200402080239.7471-1-linus.walleij@linaro.org>
On Thu, Apr 02, 2020 at 10:02:39AM +0200, Linus Walleij wrote:
> When we are using a system with big.LITTLE HMP
> configuration, we need to use EAS to schedule the
> system.
>
> As can be seen from kernel/sched/topology.c:
>
> "EAS can be used on a root domain if it meets all the following conditions:
> 1. an Energy Model (EM) is available;
> 2. the SD_ASYM_CPUCAPACITY flag is set in the sched_domain hierarchy.
> 3. no SMT is detected.
> 4. the EM complexity is low enough to keep scheduling overheads low;
> 5. schedutil is driving the frequency of all CPUs of the rd;"
>
> This means that at the very least, schedutil needs to be
> available as a scheduling policy for EAS to work on these
> systems. Make this explicit by defaulting to the schedutil
> governor if BIG_LITTLE is selected.
>
> Currently users of the TC2 board (like me) has to figure these
> dependencies out themselves and it is not helpful.
>
> Suggested-by: Arnd Bergmann <arnd@arndb.de>
> Cc: Vincent Guittot <vincent.guittot@linaro.org>
> Cc: Viresh Kumar <viresh.kumar@linaro.org>
> Cc: Sudeep Holla <sudeep.holla@arm.com>
Good to see another user of TC2 ;)
FWIW:
Acked-by: Sudeep Holla <sudeep.holla@arm.com>
--
Regards,
Sudeep
WARNING: multiple messages have this Message-ID (diff)
From: Sudeep Holla <sudeep.holla@arm.com>
To: Linus Walleij <linus.walleij@linaro.org>
Cc: Arnd Bergmann <arnd@arndb.de>,
linux-pm@vger.kernel.org, Viresh Kumar <viresh.kumar@linaro.org>,
"Rafael J . Wysocki" <rafael@kernel.org>,
Russell King <linux@armlinux.org.uk>,
Sudeep Holla <sudeep.holla@arm.com>,
linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH] cpufreq: Select schedutil when using big.LITTLE
Date: Thu, 2 Apr 2020 10:14:55 +0100 [thread overview]
Message-ID: <20200402091446.GA19366@bogus> (raw)
In-Reply-To: <20200402080239.7471-1-linus.walleij@linaro.org>
On Thu, Apr 02, 2020 at 10:02:39AM +0200, Linus Walleij wrote:
> When we are using a system with big.LITTLE HMP
> configuration, we need to use EAS to schedule the
> system.
>
> As can be seen from kernel/sched/topology.c:
>
> "EAS can be used on a root domain if it meets all the following conditions:
> 1. an Energy Model (EM) is available;
> 2. the SD_ASYM_CPUCAPACITY flag is set in the sched_domain hierarchy.
> 3. no SMT is detected.
> 4. the EM complexity is low enough to keep scheduling overheads low;
> 5. schedutil is driving the frequency of all CPUs of the rd;"
>
> This means that at the very least, schedutil needs to be
> available as a scheduling policy for EAS to work on these
> systems. Make this explicit by defaulting to the schedutil
> governor if BIG_LITTLE is selected.
>
> Currently users of the TC2 board (like me) has to figure these
> dependencies out themselves and it is not helpful.
>
> Suggested-by: Arnd Bergmann <arnd@arndb.de>
> Cc: Vincent Guittot <vincent.guittot@linaro.org>
> Cc: Viresh Kumar <viresh.kumar@linaro.org>
> Cc: Sudeep Holla <sudeep.holla@arm.com>
Good to see another user of TC2 ;)
FWIW:
Acked-by: Sudeep Holla <sudeep.holla@arm.com>
--
Regards,
Sudeep
_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
next prev parent reply other threads:[~2020-04-02 9:15 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-04-02 8:02 [PATCH] cpufreq: Select schedutil when using big.LITTLE Linus Walleij
2020-04-02 8:02 ` Linus Walleij
2020-04-02 9:14 ` Sudeep Holla [this message]
2020-04-02 9:14 ` Sudeep Holla
2020-04-02 9:44 ` Rafael J. Wysocki
2020-04-02 9:44 ` Rafael J. Wysocki
2020-04-03 5:48 ` Viresh Kumar
2020-04-03 5:48 ` Viresh Kumar
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=20200402091446.GA19366@bogus \
--to=sudeep.holla@arm.com \
--cc=arnd@arndb.de \
--cc=linus.walleij@linaro.org \
--cc=linux-arm-kernel@lists.infradead.org \
--cc=linux-pm@vger.kernel.org \
--cc=linux@armlinux.org.uk \
--cc=rafael@kernel.org \
--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 an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.