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SubjectRe: [RFC] Introduce greedy hrtimer walk on idle
On 9/23/2011 11:54 AM, Venkatesh Pallipadi wrote:
> Current hrtimer range timers reduces the number of timer interrupts by
> grouping together softexpired timers until the next unexpired timer.
> It does not look at softexpired timers that may be after the unexpired
> timer in the rbtree.
>
> Specifically, as the comment in hrtimer.c says
> * The immediate goal for using the softexpires is
> * minimizing wakeups, not running timers at the
> * earliest interrupt after their soft expiration.
> * This allows us to avoid using a Priority Search
> * Tree, which can answer a stabbing querry for
> * overlapping intervals and instead use the simple
> * BST we already have.
> * We don't add extra wakeups by delaying timers that
> * are right-of a not yet expired timer, because that
> * timer will have to trigger a wakeup anyway.
>


Since you found that it now makes a difference, I'm all for it..
Acked-by: Arjan van de Ven <arjan@linux.intel.com>

(at original introduction it was in the noise, but usage patterns
clearly changed a lot and ranges are much more prevalent now)

I would not do the sysctl/configurability thing though.... that's not
worth it.



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