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>,
Yunfeng Ye <yeyunfeng@huawei.com>,
Marcelo Tosatti <mtosatti@redhat.com>
Subject: [PATCH 5/8] tick/nohz: Update nohz_full Kconfig help
Date: Thu, 22 Apr 2021 14:01:55 +0200 [thread overview]
Message-ID: <20210422120158.33629-6-frederic@kernel.org> (raw)
In-Reply-To: <20210422120158.33629-1-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
next prev parent reply other threads:[~2021-04-22 12:02 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-22 12:01 [PATCH 0/8] tick/nohz updates v2 Frederic Weisbecker
2021-04-22 12:01 ` [PATCH 1/8] tick/nohz: Evaluate the CPU expression after the static key Frederic Weisbecker
2021-05-04 12:31 ` Peter Zijlstra
2021-04-22 12:01 ` [PATCH 2/8] tick/nohz: Conditionally restart tick on idle exit Frederic Weisbecker
2021-04-22 12:01 ` [PATCH 3/8] tick/nohz: Remove superflous check for CONFIG_VIRT_CPU_ACCOUNTING_NATIVE Frederic Weisbecker
2021-05-04 12:40 ` Peter Zijlstra
2021-04-22 12:01 ` [PATCH 4/8] tick/nohz: Update idle_exittime on actual idle exit Frederic Weisbecker
2021-04-22 12:01 ` Frederic Weisbecker [this message]
2021-04-22 12:01 ` [PATCH 6/8] tick/nohz: Only wakeup a single target cpu when kicking a task Frederic Weisbecker
2021-05-05 13:43 ` Peter Zijlstra
2021-05-10 10:39 ` Frederic Weisbecker
2021-05-10 10:48 ` Peter Zijlstra
2021-05-10 10:54 ` Frederic Weisbecker
2021-04-22 12:01 ` [PATCH 7/8] tick/nohz: Change signal tick dependency to wakeup CPUs of member tasks Frederic Weisbecker
2021-04-22 12:01 ` [PATCH 8/8] tick/nohz: Kick only _queued_ task whose tick dependency is updated Frederic Weisbecker
2021-05-05 13:57 ` Peter Zijlstra
2021-05-10 10:52 ` Frederic Weisbecker
2021-05-05 13:57 ` [PATCH 0/8] tick/nohz updates v2 Peter Zijlstra
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