Re: [RFC] Imprecise timers.

[Pavel Machek <pavel@suse.cz>]

On Mon 2008-07-28 17:36:57, Pallipadi, Venkatesh wrote:
> 
> 
> >-----Original Message-----
> >From: linux-kernel-owner@vger.kernel.org
> >[mailto:linux-kernel-owner@vger.kernel.org] On Behalf Of David
> >Woodhouse
> >Sent: Monday, July 21, 2008 8:03 PM
> >To: linux-kernel@vger.kernel.org
> >Cc: Thomas Gleixner; Ingo Molnar; arjan@infradead.org
> >Subject: [RFC] Imprecise timers.
> >
> >Many users of timers don't really care too much about exactly
> >when their
> >timer fires -- and waking a CPU to satisfy such a timer is a waste of
> >power. This patch implements a 'range' timer which will fire
> >at a 'convenient'
> >moment within given constraints.
> >
> >It's implemented by a deferrable timer at the beginning of the range,
> >which will run some time later when the CPU happens to be awake. And a
> >non-deferrable timer at the hard deadline, to ensure it really does
> >happen by then.
> >
> 
> One concern I have is drivers using range_timers thinking that they need
> some upper bound, while all they need is a simple deferrable timer. With that
> we will have multiple timers waking up the CPU all the time (say, on
> different CPUs) problem again. Even without the timers waking up all

I don't get it. Who has timers that can be deferred forever? At that
point they may simply not set the timer at all, right?

							Pavel
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