linux-kernel - Re: [PATCH 3/4] PM / devfreq: Kconfig: add DEVFREQ_DELAYED

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Date:   Mon, 9 Dec 2019 11:34:32 -0800
From:   Matthias Kaehlcke <mka@...omium.org>
To:     Kamil Konieczny <k.konieczny@...sung.com>
Cc:     Bartlomiej Zolnierkiewicz <b.zolnierkie@...sung.com>,
        Chanwoo Choi <cw00.choi@...sung.com>,
        Krzysztof Kozlowski <krzk@...nel.org>,
        Kyungmin Park <kyungmin.park@...sung.com>,
        linux-kernel@...r.kernel.org, linux-pm@...r.kernel.org,
        Marek Szyprowski <m.szyprowski@...sung.com>,
        MyungJoo Ham <myungjoo.ham@...sung.com>
Subject: Re: [PATCH 3/4] PM / devfreq: Kconfig: add DEVFREQ_DELAYED_TIMER
 option

On Mon, Dec 09, 2019 at 03:44:24PM +0100, Kamil Konieczny wrote:
> Add Kconfig option DEVFREQ_DELAYED_TIMER. If set, devfreq workqueue
> will use delayed timer from its start.

s/from its start/by default/

> 
> Signed-off-by: Kamil Konieczny <k.konieczny@...sung.com>
> ---
>  drivers/devfreq/Kconfig | 12 ++++++++++++
>  1 file changed, 12 insertions(+)
> 
> diff --git a/drivers/devfreq/Kconfig b/drivers/devfreq/Kconfig
> index 38a94df749a2..c799917c34c9 100644
> --- a/drivers/devfreq/Kconfig
> +++ b/drivers/devfreq/Kconfig
> @@ -74,6 +74,18 @@ config DEVFREQ_GOV_PASSIVE
>  	  through sysfs entries. The passive governor recommends that
>  	  devfreq device uses the OPP table to get the frequency/voltage.
>  
> +comment "DEVFREQ Options"
> +
> +config DEVFREQ_DELAYED_TIMER
> +	bool "Use delayed timer in Simple Ondemand Governor"

Is the use really limited to the Simple Ondemand Governor? I don't think
so, at least the Tegra devfreq driver also does monitoring and others
might follow.


> +	default false
> +	help
> +	  Simple Ondemand Governor uses polling for reading buses counters.
> +	  A default timer used is deferred, which saves power, but can
> +	  miss increased demand for higher bus frequency if timer was
> +	  assigned to idle cpu. If you want to change this to delayed
> +	  timer at the cost of more power used, say Yes here.
> +
>  comment "DEVFREQ Drivers"
>  
>  config ARM_EXYNOS_BUS_DEVFREQ


This patch on it's own does nothing. Squash it with '[4/4] PM / devfreq:
use delayed work if DEVFREQ_DELAYED_TIMER set'.