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    SubjectRe: [RFC] Imprecise timers.
    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
    --
    (english) http://www.livejournal.com/~pavelmachek
    (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html


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