Message-id: <52F1DDA8.90605@samsung.com>
Date: Wed, 05 Feb 2014 10:43:52 +0400
From: Alexey Perevalov <a.perevalov@samsung.com>
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To: Thomas Gleixner <tglx@linutronix.de>
Cc: John Stultz <john.stultz@linaro.org>, linux-kernel@vger.kernel.org,
        anton@enomsg.org, kyungmin.park@samsung.com, akpm@linux-foundation.org,
        cw00.choi@samsung.com
Subject: Re: [PATCH v2 0/3] Deferrable timers support for timerfd API
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 <52DEC6A3.9020600@linaro.org> <52E606D8.6000401@samsung.com>
 <alpine.DEB.2.02.1402041419420.24986@ionos.tec.linutronix.de>
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On 02/04/2014 08:10 PM, Thomas Gleixner wrote:
> On Mon, 27 Jan 2014, Alexey Perevalov wrote:
>> On 01/21/2014 11:12 PM, John Stultz wrote:
>>> Thomas: Any thought here? Should we be trying to unify the timerfd flags
>>> and the posix timer flags (specifically things like TIMER_CANCEL_ON_SET,
>>> which is currently timerfd-only)?  Should a deferrable flag be added to
>>> the hrtimer core or left to the timer wheel?
> The timer cancel on set was added only to timerfd because timerfd is a
> non posix interface and we are halfways free to add stuff to
> it. Adding extra flags to the real posix timer interfaces is a
> different story.
And what about "deferrable" possibility for hrtimers, do you consider it 
reasonable?

>
> What's the rationale for a deferrable flag for user space interfaces?
The main reason of this was do not call user space timers on system 
idle, to safe power on embedded systems, especially in case of NOHZ.

>
> Thanks,
>
> 	tglx
>


-- 
Best regards,
Alexey Perevalov
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