Messages in this thread Patch in this message | | | From | "Paul E. McKenney" <> | Subject | [PATCH tip/core/rcu 2/5] rcu: Update RCU_FAST_NO_HZ help text | Date | Tue, 30 Oct 2012 10:19:20 -0700 |
| |
From: "Paul E. McKenney" <paul.mckenney@linaro.org>
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> --- init/Kconfig | 15 +++++++-------- 1 files changed, 7 insertions(+), 8 deletions(-)
diff --git a/init/Kconfig b/init/Kconfig index 6fdd6e3..b63e798 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. -- 1.7.8
| |