From: Frederic Weisbecker <fweisbec@gmail.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: LKML <linux-kernel@vger.kernel.org>,
Ingo Molnar <mingo@kernel.org>,
Nicolas Pitre <nicolas.pitre@linaro.org>,
"Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
Steven Rostedt <rostedt@goodmis.org>,
Thomas Gleixner <tglx@linutronix.de>,
Viresh Kumar <viresh.kumar@linaro.org>
Subject: Re: [PATCH 09/10] nohz: Switch nohz full timekeeper to dynticks idle on top of sysidle detection
Date: Wed, 30 Jul 2014 00:04:45 +0200 [thread overview]
Message-ID: <20140729220443.GD14520@localhost.localdomain> (raw)
In-Reply-To: <20140729121753.GZ3935@laptop>
On Tue, Jul 29, 2014 at 02:17:53PM +0200, Peter Zijlstra wrote:
> On Mon, Jul 28, 2014 at 07:37:35PM +0200, Frederic Weisbecker wrote:
>
> > @@ -745,7 +747,7 @@ static bool can_stop_idle_tick(int cpu, struct tick_sched *ts)
> > * if there are full dynticks CPUs around
> > */
> > if (tick_do_timer_cpu == cpu)
> > - return false;
> > + return rcu_sys_is_idle();
> > }
>
> I still feel its entirely upside down to rely on RCU for this...
RCU had this feature internally for a while. Then comes nohz. I guess in
a perfect world we would make it a library that RCU and nohz could use.
It's probably possible to do but right now it is too tied to RCU internals.
next prev parent reply other threads:[~2014-07-29 22:04 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-07-28 17:37 [PATCH 00/10] nohz: Support sysidle (+ some more nohz kick cleanups) Frederic Weisbecker
2014-07-28 17:37 ` [PATCH 01/10] smp: Introduce void kick_cpu_async() Frederic Weisbecker
2014-07-28 17:37 ` [PATCH 02/10] nohz: Kick full dynticks timer targets with an empty IPI Frederic Weisbecker
2014-07-29 11:33 ` Peter Zijlstra
2014-07-29 21:53 ` Frederic Weisbecker
2014-07-28 17:37 ` [PATCH 03/10] rcu: Kick full dynticks CPU on extended grace period with kick_cpu_async() Frederic Weisbecker
2014-07-28 17:37 ` [PATCH 04/10] nohz: Appropriate timekeeper kick on sysidle break Frederic Weisbecker
2014-07-28 17:37 ` [PATCH 05/10] smp: Fast path check on IPI list Frederic Weisbecker
2014-07-29 12:07 ` Peter Zijlstra
2014-07-29 21:54 ` Frederic Weisbecker
2014-07-29 21:55 ` Frederic Weisbecker
2014-07-28 17:37 ` [PATCH 06/10] nohz: Define meaningful symbol for nohz full timekeeper Frederic Weisbecker
2014-07-28 17:37 ` [PATCH 07/10] nohz: Enforce timekeeping on CPU 0 Frederic Weisbecker
2014-07-29 12:12 ` Peter Zijlstra
2014-07-30 13:23 ` Frederic Weisbecker
2014-07-28 17:37 ` [PATCH 08/10] nohz: Fetch timekeeping max deferment only for timekeeper Frederic Weisbecker
2014-07-28 17:37 ` [PATCH 09/10] nohz: Switch nohz full timekeeper to dynticks idle on top of sysidle detection Frederic Weisbecker
2014-07-29 12:17 ` Peter Zijlstra
2014-07-29 22:04 ` Frederic Weisbecker [this message]
2014-07-28 17:37 ` [PATCH 10/10] nohz: Warn on illegal timekeeper switch in nohz full Frederic Weisbecker
-- strict thread matches above, loose matches on Subject: below --
2014-07-19 0:44 [RFC PATCH 00/10] nohz: Support sysidle (and some more cleanups) Frederic Weisbecker
2014-07-19 0:44 ` [PATCH 09/10] nohz: Switch nohz full timekeeper to dynticks idle on top of sysidle detection Frederic Weisbecker
2014-07-21 17:50 ` Paul E. McKenney
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