Re: [PATCH] a local-timer-free version of RCU

From: Paul E. McKenney
Date: Wed Nov 10 2010 - 23:20:31 EST


On Wed, Nov 10, 2010 at 06:31:11PM +0100, Peter Zijlstra wrote:
> On Wed, 2010-11-10 at 16:54 +0100, Frederic Weisbecker wrote:
> > run the sched tick and if there was nothing to do
> > for some time and we are in userspace, deactivate it.
>
> Not for some time, immediately, have the tick track if it was useful, if
> it was not, have it stop itself, like:
>
> tick()
> {
> int stop = 1;
>
> if (nr_running > 1)
> stop = 0;
>
> if(rcu_needs_cpu())
> stop = 0;
>
> ...
>
>
> if (stop)
> enter_nohz_mode();
> }

I am still holding out for a dyntick-hpc version of RCU that does not
need the tick. ;-)

Thanx, Paul
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