lkml.org 
[lkml]   [2015]   [Feb]   [18]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Date
From
SubjectRe: [PATCH RFC 12/12] Documentation: thermal docbook: introduce governor chapter
Hi Eduardo,

On Mon, Feb 09, 2015 at 09:34:13PM +0000, Eduardo Valentin wrote:
> In this patch we add a chapter in the thermal docbook to
> describe the existing governors. The chapter contains
> one section per governor.
>
> Each governor description includes the respective code documentation.
> Each governor section contains a description of the governor
> logic.
>
> Signed-off-by: Eduardo Valentin <edubezval@gmail.com>
> ---
> Documentation/DocBook/thermal.tmpl | 67 ++++++++++++++++++++++++++++++++++++++
> 1 file changed, 67 insertions(+)
>
> diff --git a/Documentation/DocBook/thermal.tmpl b/Documentation/DocBook/thermal.tmpl
> index d6ebbea..cf1a198 100644
> --- a/Documentation/DocBook/thermal.tmpl
> +++ b/Documentation/DocBook/thermal.tmpl
> @@ -212,6 +212,73 @@
> </glossary>
> </sect1>
> </chapter>
> +
> + <chapter id="governors">
> + <title>Thermal Governors</title>
> + <para>
> + </para>
> +
> + <sect1 id="step_wise">
> + <title>step_wise Thermal Governor</title>
> + <para>Step Wise uses the trend of the thermal zone to
> + throttle. If the thermal zone is 'heating up' this
> + throttles all the cooling devices associated with the
> + zone and its particular trip point, by one step. If the
> + zone is 'cooling down' it brings back the performance
> + of the devices by one step.
> + </para>
> +!Idrivers/thermal/step_wise.c
> +!Pdrivers/thermal/step_wise.c Algorithm
> + </sect1>
> + <sect1 id="fair_share">
> + <title>fair_share Thermal Governor</title>
> + <para>Fair Share Governor uses three parameters to
> + calculate the new throttle state of the cooling devices
> + associated with the given zone. Parameters used for
> + Throttling:
> + </para>
> + <itemizedlist mark='opencircle'>
> + <listitem>P1. max_state: Maximum throttle state
> + exposed by the cooling device.</listitem>
> + <listitem>P2. weight[i]/100:</listitem>
> + <listitem>How 'effective' the 'i'th device is,
> + in cooling the given zone.</listitem>
> + <listitem>P3.
> + cur_trip_level/max_no_of_trips:</listitem>
> + </itemizedlist>
> + <para>This describes the extent to which the devices
> + should be throttled. We do not want to throttle too
> + much when we trip a lower temperature, whereas the
> + throttling is at full swing if we trip critical levels.
> + Heavily assumes the trip points are in ascending order
> + new_state of cooling device = P3 * P2 * P1.
> + </para>

This seems to be heavily based on the kerneldoc in fair_share.c .
Wouldn't it be better to do a similar trick to what you did in
step_wise? That is, move that kerneldoc into an "Algorithm" entry and
include it here. That way we avoid the duplication of the
documentation.

Cheers,
Javi

> +!Idrivers/thermal/fair_share.c
> + </sect1>
> + <sect1 id="bang_bang">
> + <title>bang_bang Thermal Governor</title>
> + <para>The Bang Bang Governor has a two point regulation
> + logic, deliver cooling state depending on the previous
> + state shown in this diagram: </para>
> + <para>If the fan is not running and temperature exceeds
> + trip_temp, the fan gets turned on. In case the fan is
> + running, temperature must fall below (trip_temp - hyst)
> + so that the fan gets turned off again.
> + </para>
> +!Idrivers/thermal/gov_bang_bang.c
> + </sect1>
> + <sect1 id="user_space">
> + <title>user_space Thermal Governor</title>
> + <para> The User Space governor is outside the Kernel.
> + The Thermal Framework hands off the entire control to
> + userland if the User Space governor is assigned to a
> + thermal zone. A KOBJ_CHANGE UEvent notification is sent
> + to userland whenever a governor needs to take an
> + action.
> + </para>
> +!Idrivers/thermal/user_space.c
> + </sect1>
> + </chapter>
> <chapter id="api">
> <title>Thermal Device Driver Writer API reference</title>
> <para> This Chapter contains an API reference for Thermal driver writers.
> --
> 2.1.3
>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-pm" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at http://vger.kernel.org/majordomo-info.html
>


\
 
 \ /
  Last update: 2015-02-18 17:41    [W:0.187 / U:0.504 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site