[PATCH 05/10] tick/nohz: Update nohz_full Kconfig help

From: Frederic Weisbecker
Date: Wed May 12 2021 - 19:43:27 EST


CONFIG_NO_HZ_FULL behaves just like CONFIG_NO_HZ_IDLE by default.
Reassure distros about it.

Acked-by: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Signed-off-by: Frederic Weisbecker <frederic@xxxxxxxxxx>
Cc: Yunfeng Ye <yeyunfeng@xxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Marcelo Tosatti <mtosatti@xxxxxxxxxx>
Cc: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
---
kernel/time/Kconfig | 11 ++++++-----
1 file changed, 6 insertions(+), 5 deletions(-)

diff --git a/kernel/time/Kconfig b/kernel/time/Kconfig
index 83e158d016ba..6649e1d2dba5 100644
--- a/kernel/time/Kconfig
+++ b/kernel/time/Kconfig
@@ -117,13 +117,14 @@ config NO_HZ_FULL
the task mostly runs in userspace and has few kernel activity.

You need to fill up the nohz_full boot parameter with the
- desired range of dynticks CPUs.
+ desired range of dynticks CPUs to use it. This is implemented at
+ the expense of some overhead in user <-> kernel transitions:
+ syscalls, exceptions and interrupts.

- This is implemented at the expense of some overhead in user <-> kernel
- transitions: syscalls, exceptions and interrupts. Even when it's
- dynamically off.
+ By default, without passing nohz_full parameter, this behaves just
+ like NO_HZ_IDLE.

- Say N.
+ If you're a distro say Y.

endchoice

--
2.25.1