linux-kernel - Re: [PATCH v2 00/15] timers: Cleanup delay/sleep related mess

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Message-ID: <87ed5aietj.fsf@somnus>
Date: Mon, 23 Sep 2024 17:12:56 +0200
From: Anna-Maria Behnsen <anna-maria@...utronix.de>
To: Christophe JAILLET <christophe.jaillet@...adoo.fr>
Cc: linux-kernel@...r.kernel.org, Len Brown <len.brown@...el.com>, "Rafael
 J. Wysocki" <rafael@...nel.org>, Andrew Morton
 <akpm@...ux-foundation.org>, damon@...ts.linux.dev, linux-mm@...ck.org,
 SeongJae Park <sj@...nel.org>, Arnd Bergmann <arnd@...db.de>,
 linux-arch@...r.kernel.org, Heiner Kallweit <hkallweit1@...il.com>, "David
 S. Miller" <davem@...emloft.net>, Andy Whitcroft <apw@...onical.com>, Joe
 Perches <joe@...ches.com>, Dwaipayan Ray <dwaipayanray1@...il.com>, Liam
 Girdwood <lgirdwood@...il.com>, Mark Brown <broonie@...nel.org>, Andrew
 Lunn <andrew@...n.ch>, Jaroslav Kysela <perex@...ex.cz>, Takashi Iwai
 <tiwai@...e.com>, netdev@...r.kernel.org, linux-sound@...r.kernel.org,
 Michael Ellerman <mpe@...erman.id.au>, Nathan Lynch
 <nathanl@...ux.ibm.com>, linuxppc-dev@...ts.ozlabs.org, Mauro Carvalho
 Chehab <mchehab@...nel.org>, linux-media@...r.kernel.org, Frederic
 Weisbecker <frederic@...nel.org>, Thomas Gleixner <tglx@...utronix.de>,
 Jonathan Corbet <corbet@....net>
Subject: Re: [PATCH v2 00/15] timers: Cleanup delay/sleep related mess

Christophe JAILLET <christophe.jaillet@...adoo.fr> writes:

> Le 16/09/2024 à 22:20, Christophe JAILLET a écrit :
>> Le 11/09/2024 à 07:13, Anna-Maria Behnsen a écrit :
>>> Hi,
>>>
>>> a question about which sleeping function should be used in 
>>> acpi_os_sleep()
>>> started a discussion and examination about the existing documentation and
>>> implementation of functions which insert a sleep/delay.
>>>
>>> The result of the discussion was, that the documentation is outdated and
>>> the implemented fsleep() reflects the outdated documentation but doesn't
>>> help to reflect reality which in turns leads to the queue which covers 
>>> the
>>> following things:
>>>
>>> - Split out all timeout and sleep related functions from hrtimer.c and 
>>> timer.c
>>>    into a separate file
>>>
>>> - Update function descriptions of sleep related functions
>>>
>>> - Change fsleep() to reflect reality
>>>
>>> - Rework all comments or users which obviously rely on the outdated
>>>    documentation as they reference "Documentation/timers/timers- 
>>> howto.rst"
>>>
>>> - Last but not least (as there are no more references): Update the 
>>> outdated
>>>    documentation and move it into a file with a self explaining file name
>>>
>>> The queue is available here and applies on top of tip/timers/core:
>>>
>>>    git://git.kernel.org/pub/scm/linux/kernel/git/anna-maria/linux- 
>>> devel.git timers/misc
>>>
>>> Signed-off-by: Anna-Maria Behnsen <anna-maria@...utronix.de>
>> 
>> Hi,
>> 
>> not directly related to your serie, but some time ago I sent a patch to 
>> micro-optimize Optimize usleep_range(). (See [1])
>> 
>> The idea is that the 2 parameters of usleep_range() are usually 
>> constants and some code reordering could easily let the compiler compute 
>> a few things at compilation time.
>> 
>> There was consensus on the value of the change (see [2]), but as you are 
>
> Typo: there was *no* consensus...
>
>> touching things here, maybe it makes sense now to save a few cycles at 
>> runtime and a few bytes of code?
>> 

Sorry for the late reply. I'll check it and will come back to you.

Thanks,
	Anna-Maria