* Linus Torvalds <[EMAIL PROTECTED]> wrote:
> On Mon, 16 Jul 2007, Paul E. McKenney wrote:
> >
> > On Wed, Jun 27, 2007 at 03:36:34PM -0400, Steven Rostedt wrote:
> > > I believe this was originally done by Dipankar Sarma. I pulled these
> > > changes from the -rt kernel.
> > >
> > > For better preformance, RCU should use a softirq instead of a
> > > tasklet.
> >
> > Acked-by: Paul E. McKenney <[EMAIL PROTECTED]>
> > Tested-by: Paul E. McKenney <[EMAIL PROTECTED]>
> >
> > Tested with both kernbench and rcutorture on i386, x86_64, and ppc64.
>
> Btw, are there any numbers on this? Is this whole thing actually
> noticeable?
i doubt it's noticeable, because the RCU tasklet was not a "true" global
tasklet, it was an array of tasklets put into a PER_CPU array. (which
kind of defeats the purpose of tasklets)
So there should be no/little scalability disadvantage from this type of
use of tasklets, and the tasklet use was at most a wart and a small,
constant micro-cost that is likely masked by other costs. (and rcu never
used any of the fancier tasklet ops like tasklet_disable() either)
Ingo
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