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    SubjectRe: [RFC] Imprecise timers.
    On Tue, 22 Jul 2008 09:19:02 +0200
    Rene Herman <rene.herman@keyaccess.nl> wrote:

    > On 22-07-08 05:02, David Woodhouse wrote:
    >
    > > 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.
    >
    > Are there actually users for this (not just in theory)? The
    > deferrable timer sort of sounds like all I'd ever want if I, as you
    > say, wouldn't really care...

    there's a few; mostly around hardware timeout..For example Stephen want
    it for his drivers.

    EXT3 journal flushing is another one where we can easily say
    "between 4 and 7 seconds" rather than "exactly at 5"


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