Messages in this thread | | | Date | Thu, 6 Sep 2012 13:39:57 -0700 | From | "Paul E. McKenney" <> | Subject | Re: [PATCH RFC tip/core/rcu] Add callback-free CPUs |
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On Thu, Sep 06, 2012 at 08:21:50PM +0200, Peter Zijlstra wrote: > On Thu, 2012-09-06 at 10:46 -0700, Paul E. McKenney wrote: > > Getting these > > CPUs into adaptive-tick mode more quickly reduces OS jitter, which is > > one big expected benefit of adaptive-tick mode. > > I'm not sure I agree with that statement. Its a transition thing and > therefore statistically irrelevant on the whole -- assuming we > transition rarely. > > And for those who cannot deal with the transition effects, a barrier was > proposed which would wait until the system hit this state -- although > the specific implementation of this isn't clear yet afaik. > > I very much think we should focus on getting adaptive tick working as > simple as possible and worry about transition effects later, if at all.
I expect that the RT folks will be interested as well, and they will likely care about the transition effects because they degrade worst-case behavior.
Thanx, Paul
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