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From: Frederic Weisbecker <frederic@kernel.org>
To: Peter Zijlstra <peterz@infradead.org>,
	Thomas Gleixner <tglx@linutronix.de>
Cc: LKML <linux-kernel@vger.kernel.org>,
	Frederic Weisbecker <frederic@kernel.org>,
	"Rafael J . Wysocki" <rafael.j.wysocki@intel.com>,
	Ti Zhou <x2019cwm@stfx.ca>, Yunfeng Ye <yeyunfeng@huawei.com>,
	"Paul E . McKenney" <paulmck@kernel.org>,
	Marcelo Tosatti <mtosatti@redhat.com>,
	Ingo Molnar <mingo@kernel.org>
Subject: [PATCH 07/10] tick/nohz: Update nohz_full Kconfig help
Date: Thu, 11 Mar 2021 13:37:05 +0100	[thread overview]
Message-ID: <20210311123708.23501-8-frederic@kernel.org> (raw)
In-Reply-To: <20210311123708.23501-1-frederic@kernel.org>

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

Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Cc: Yunfeng Ye <yeyunfeng@huawei.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Marcelo Tosatti <mtosatti@redhat.com>
Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
---
 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


  parent reply	other threads:[~2021-03-11 12:38 UTC|newest]

Thread overview: 35+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-03-11 12:36 [PATCH 00/10] tick/nohz updates Frederic Weisbecker
2021-03-11 12:36 ` [PATCH 01/10] tick/nohz: Prevent tick_nohz_get_sleep_length() from returning negative value Frederic Weisbecker
2021-03-16 12:21   ` Peter Zijlstra
2021-03-16 13:37     ` Frederic Weisbecker
2021-03-16 14:35       ` Peter Zijlstra
2021-03-16 14:53         ` Frederic Weisbecker
2021-03-16 15:26           ` Rafael J. Wysocki
2021-03-16 15:57             ` 回复: " Zhou Ti (x2019cwm)
2021-03-16 16:08               ` Zhou Ti (x2019cwm)
2021-03-16 16:25                 ` Peter Zijlstra
2021-03-17 21:49                   ` Zhou Ti (x2019cwm)
2021-03-25 13:14                 ` Frederic Weisbecker
2021-03-25 18:56                   ` Rafael J. Wysocki
2021-03-25 19:18                     ` Zhou Ti (x2019cwm)
2021-03-25 19:50                       ` Rafael J. Wysocki
2021-03-25 20:37                         ` Zhou Ti (x2019cwm)
2021-03-26 17:01                           ` Rafael J. Wysocki
2021-03-26 17:53                             ` Zhou Ti (x2019cwm)
2021-03-26 18:54                               ` Rafael J. Wysocki
2021-03-26 22:53                                 ` Zhou Ti (x2019cwm)
2021-03-29 12:44                                   ` Rafael J. Wysocki
2021-03-29 14:49                                     ` Zhou Ti (x2019cwm)
2021-03-11 12:37 ` [PATCH 02/10] tick/nohz: Add tick_nohz_full_this_cpu() Frederic Weisbecker
2021-03-16 12:28   ` Peter Zijlstra
2021-03-16 13:05     ` Frederic Weisbecker
2021-03-11 12:37 ` [PATCH 03/10] tick/nohz: Conditionally restart tick on idle exit Frederic Weisbecker
2021-03-11 12:37 ` [PATCH 04/10] tick/nohz: Remove superflous check for CONFIG_VIRT_CPU_ACCOUNTING_NATIVE Frederic Weisbecker
2021-03-11 12:37 ` [PATCH 05/10] tick/nohz: Update idle_exittime on actual idle exit Frederic Weisbecker
2021-03-11 12:37 ` [PATCH 06/10] timer: Report ignored local enqueue in nohz mode Frederic Weisbecker
2021-03-16 15:27   ` Peter Zijlstra
2021-03-25 13:07     ` Frederic Weisbecker
2021-03-11 12:37 ` Frederic Weisbecker [this message]
2021-03-11 12:37 ` [PATCH 08/10] tick/nohz: Only wakeup a single target cpu when kicking a task Frederic Weisbecker
2021-03-11 12:37 ` [PATCH 09/10] tick/nohz: Change signal tick dependency to wakeup CPUs of member tasks Frederic Weisbecker
2021-03-11 12:37 ` [PATCH 10/10] tick/nohz: Kick only _queued_ task whose tick dependency is updated Frederic Weisbecker

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