Re: Question about usage of RCU in the input layer

From: Arjan van de Ven
Date: Sun Mar 22 2009 - 15:46:20 EST


On Sun, 22 Mar 2009 09:53:24 -0700
"Paul E. McKenney" <paulmck@xxxxxxxxxxxxxxxxxx> wrote:

> > > How many synchronize_rcu() calls are you seeing on the boot path?
> >
> > I see 20 that hit the above code path (eg ones that wait) until
> > userspace starts.
>
> So with well-behaved readers, the full sequence would be worth
> something like 50-60 milliseconds.

yeah it's about 10% if the total kernel boot time.. so it does start to
matter

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Arjan van de Ven Intel Open Source Technology Centre
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