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authorPaul E. McKenney <paul.mckenney@linaro.org>2012-10-07 09:26:13 -0700
committerPaul E. McKenney <paulmck@linux.vnet.ibm.com>2012-10-23 14:54:07 -0700
commitba49df4767d4fa5bbd2af3a51709fb81f94264ec (patch)
tree5fe4594735aff61cb4b6b9f53885f35e3e05a415
parent4d9a5d4319e22670ec6d6227e12b54f361c46d0f (diff)
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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: Paul E. McKenney <paul.mckenney@linaro.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
-rw-r--r--init/Kconfig15
1 files changed, 7 insertions, 8 deletions
diff --git a/init/Kconfig b/init/Kconfig
index 6fdd6e339326..b63e7982c1c6 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -582,14 +582,13 @@ config RCU_FAST_NO_HZ
depends on NO_HZ && SMP
default n
help
- This option causes RCU to attempt to accelerate grace periods
- in order to allow CPUs to enter dynticks-idle state more
- quickly. On the other hand, this option increases the overhead
- of the dynticks-idle checking, particularly on systems with
- large numbers of CPUs.
-
- Say Y if energy efficiency is critically important, particularly
- if you have relatively few CPUs.
+ This option causes RCU to attempt to accelerate grace periods in
+ order to allow CPUs to enter dynticks-idle state more quickly.
+ On the other hand, this option increases the overhead of the
+ dynticks-idle checking, thus degrading scheduling latency.
+
+ Say Y if energy efficiency is critically important, and you don't
+ care about real-time response.
Say N if you are unsure.