linux-kernel - Re: [PATCH 1/4] timer: Added usleep[

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Message-ID: <4C509BA3.7090403@codeaurora.org>
Date:	Wed, 28 Jul 2010 14:05:39 -0700
From:	Patrick Pannuto <ppannuto@...eaurora.org>
To:	Andrew Morton <akpm@...ux-foundation.org>
CC:	linux-kernel@...r.kernel.org, apw@...onical.com, corbet@....net,
	Thomas Gleixner <tglx@...utronix.de>,
	Ingo Molnar <mingo@...e.hu>,
	Arjan van de Ven <arjan@...ux.intel.com>,
	Akinobu Mita <akinobu.mita@...il.com>
Subject: Re: [PATCH 1/4] timer: Added usleep[_range] timer

On 07/28/2010 01:58 PM, Andrew Morton wrote:
> On Wed, 28 Jul 2010 13:47:46 -0700
> Patrick Pannuto <ppannuto@...eaurora.org> wrote:
> 
>>> This is different from the patch I merged and I'm not seeing any
>>> explanation for the change.
>>>
>>> The implementation of usleep() looks odd.  The longer we sleep, the
>>> greater the possible inaccuracy.  A code comment which explains the
>>> thinking and which warns people about the implications is needed.
> 
> I wanna code comment!
> 

I understand -- will do (if this even survives, which is unlikely)

> My main concern is that someone will type usleep(50) and won't realise
> that it goes and sleeps for 100 usecs and their code gets slow as a
> result.  This sort of thing takes *years* to discover and fix.  If we'd
> forced them to type usleep_range() instead, it would never have happened.

In that case, it would push me in the direction of only providing
usleep_range, and thus forcing people to think about it that way;
leave slack decisions to people who know what tolerances are acceptable.

-- 
Employee of Qualcomm Innovation Center, Inc.
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum
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