Messages in this thread | | | Date | Fri, 20 Feb 2015 17:54:09 +0100 | From | Peter Zijlstra <> | Subject | Re: [PATCH tip/core/rcu 0/4] Programmatic nestable expedited grace periods |
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On Fri, Feb 20, 2015 at 08:37:37AM -0800, Paul E. McKenney wrote: > On Fri, Feb 20, 2015 at 10:11:07AM +0100, Peter Zijlstra wrote: > > So I though we wanted to get rid / limit the expedited stuff because its > > IPI happy, and here its spreading. > > Well, at least it no longer IPIs idle CPUs. ;-) > > And this is during boot, when a few extra IPIs should not be a big deal.
Well the one application now is during boot; but you expose the interface for all to use, and therefore someone will.
> > Does it really make a machine boot much faster? Why are people using > > synchronous gp primitives if they care about speed? Should we not fix > > that instead? > > The report I heard was that it provided 10-15% faster boot times.
That's not insignificant; got more details? I think we should really look at why people are using the sync primitives.
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