Messages in this thread | | | Date | Sun, 6 Sep 2009 08:24:41 +0200 | From | Pavel Machek <> | Subject | Re: RCU Kconfig help text |
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On Sat 2009-09-05 13:01:46, Paul E. McKenney wrote: > On Sat, Sep 05, 2009 at 09:27:10AM -0400, Valdis.Kletnieks@vt.edu wrote: > > init/Kconfig says: > > > > "choice > > prompt "RCU Implementation" > > default TREE_RCU > > > > config TREE_RCU > > bool "Tree-based hierarchical RCU" > > help > > This option selects the RCU implementation that is > > designed for very large SMP system with hundreds or > > thousands of CPUs. It also scales down nicely to > > smaller systems. > > > > config TREE_PREEMPT_RCU > > bool "Preemptable tree-based hierarchical RCU" > > depends on PREEMPT > > help > > This option selects the RCU implementation that is > > designed for very large SMP systems with hundreds or > > thousands of CPUs, but for which real-time response > > is also required. > > > > endchoice" > > > > This leaves somebody who has a laptop wondering which choice is best for > > a system with only one or two cores that has CONFIG_PREEMPT defined. One > > choice says it scales down nicely, the other explicitly has a 'depends on > > PREEMPT' attached to it... > > > > (Yes, I realize in practice, the RCU sections on a laptop are probably usually > > so short they don't matter in practice. I finally concluded TREE_PREEMPT was > > apparently a rename of CONFIG_PREEMPT_RCU and went with that since that was > > working for me before...) > > Good point -- I will add the "It also scales down nicely to smaller > systems" to TREE_PREEMPT_RCU. > > For -really- small systems, TINY_RCU will hopefully be there at some > point, but it can only handle single-CPU systems.
If so, call it 'UP_RCU' or 'UNIPROCESSOR_RCU'? Pavel
-- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
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