Commit ba49df47 authored by Paul E. McKenney's avatar Paul E. McKenney
Browse files

rcu: Update RCU_FAST_NO_HZ help text 



The RCU_FAST_NO_HZ help text included a warning about overhead on large
systems, but that issue has since been resolved.  The main remaining
issue with RCU_FAST_NO_HZ is increased real-time latency.  This commit
therefore updates the help text accordingly.

Signed-off-by: default avatarPaul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: default avatarPaul E. McKenney <paulmck@linux.vnet.ibm.com>
parent 4d9a5d43

init/Kconfig

+7 −8
Original line number Original line Diff line number Diff line
@@ -582,14 +582,13 @@ config RCU_FAST_NO_HZ 
	depends on NO_HZ && SMP

	depends on NO_HZ && SMP

	default n

	default n

	help

	help

	  This option causes RCU to attempt to accelerate grace periods

	  This option causes RCU to attempt to accelerate grace periods in

	  in order to allow CPUs to enter dynticks-idle state more

	  order to allow CPUs to enter dynticks-idle state more quickly.

	  quickly.  On the other hand, this option increases the overhead

	  On the other hand, this option increases the overhead of the

	  of the dynticks-idle checking, particularly on systems with

	  dynticks-idle checking, thus degrading scheduling latency.

	  large numbers of CPUs.





	  Say Y if energy efficiency is critically important, and you don't

	  Say Y if energy efficiency is critically important, particularly

	  	care about real-time response.

	  	if you have relatively few CPUs.





	  Say N if you are unsure.

	  Say N if you are unsure.