From: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>,
Christoph Lameter <cl@linux.com>,
"Li, Aubrey" <aubrey.li@linux.intel.com>,
Andi Kleen <ak@linux.intel.com>, Aubrey Li <aubrey.li@intel.com>,
tglx@linutronix.de, len.brown@intel.com, rjw@rjwysocki.net,
tim.c.chen@linux.intel.com, arjan@linux.intel.com,
yang.zhang.wz@gmail.com, x86@kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [RFC PATCH v1 00/11] Create fast idle path for short idle periods
Date: Wed, 12 Jul 2017 08:54:58 -0700 [thread overview]
Message-ID: <20170712155458.GW2393@linux.vnet.ibm.com> (raw)
In-Reply-To: <20170712122249.u6y4ymmk6qwvog57@hirez.programming.kicks-ass.net>
On Wed, Jul 12, 2017 at 02:22:49PM +0200, Peter Zijlstra wrote:
> On Tue, Jul 11, 2017 at 11:09:31AM -0700, Paul E. McKenney wrote:
> > On Tue, Jul 11, 2017 at 06:34:22PM +0200, Peter Zijlstra wrote:
> > > Also, RCU_FAST_NO_HZ will make a fairly large difference here.. Paul
> > > what's the state of that thing, do we actually want that or not?
> >
> > If you are battery powered and don't have tight real-time latency
> > constraints, you want it -- it has represent a 30-40% boost in battery
> > lifetime for some low-utilization battery-powered devices. Otherwise,
> > probably not.
>
> Would it make sense to hook that off of tick_nohz_idle_enter(); in
> specific the part where we actually stop the tick; instead of every
> idle?
The actions RCU takes on RCU_FAST_NO_HZ depend on the current state of
the CPU's callback lists, so it seems to me that the decision has to
be made on each idle entry.
Now it might be possible to make the checks more efficient, and doing
that is on my list.
Or am I missing your point?
Thanx, Paul
next prev parent reply other threads:[~2017-07-12 15:55 UTC|newest]
Thread overview: 114+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-07-10 1:38 [RFC PATCH v1 00/11] Create fast idle path for short idle periods Aubrey Li
2017-07-10 1:38 ` [RFC PATCH v1 01/11] sched/idle: create a fast " Aubrey Li
2017-07-10 1:38 ` [RFC PATCH v1 02/11] cpuidle: attach cpuidle governor statistics to the per-CPU device Aubrey Li
2017-07-10 1:38 ` [RFC PATCH v1 03/11] cpuidle: introduce cpuidle governor for idle prediction Aubrey Li
2017-07-12 12:16 ` Peter Zijlstra
2017-07-10 1:38 ` [RFC PATCH v1 04/11] sched/idle: make the fast idle path for short idle periods Aubrey Li
2017-07-11 12:58 ` Paul E. McKenney
2017-07-11 16:33 ` Frederic Weisbecker
2017-07-11 18:11 ` Paul E. McKenney
2017-07-12 3:19 ` Li, Aubrey
2017-07-12 5:03 ` Paul E. McKenney
2017-07-12 5:22 ` Li, Aubrey
2017-07-12 12:19 ` Peter Zijlstra
2017-07-10 1:38 ` [RFC PATCH v1 05/11] cpuidle: update idle statistics before cpuidle governor Aubrey Li
2017-07-10 1:38 ` [RFC PATCH v1 06/11] timers: keep sleep length updated as needed Aubrey Li
2017-07-10 1:38 ` [RFC PATCH v1 07/11] cpuidle: make idle residency update more generic Aubrey Li
2017-07-10 1:38 ` [RFC PATCH v1 08/11] cpuidle: menu: remove reduplicative implementation Aubrey Li
2017-07-10 1:38 ` [RFC PATCH v1 09/11] cpuidle: menu: feed cpuidle prediction to menu governor Aubrey Li
2017-07-10 1:38 ` [RFC PATCH v1 10/11] cpuidle: update cpuidle governor when needed Aubrey Li
2017-07-10 1:38 ` [RFC PATCH v1 11/11] sched/idle: Add a tuning knob to allow changing fast idle threshold Aubrey Li
2017-07-10 8:46 ` [RFC PATCH v1 00/11] Create fast idle path for short idle periods Peter Zijlstra
2017-07-10 9:29 ` Wanpeng Li
2017-07-10 13:59 ` Li, Aubrey
2017-07-10 14:46 ` Andi Kleen
2017-07-10 16:42 ` Peter Zijlstra
2017-07-10 17:27 ` Andi Kleen
2017-07-11 4:40 ` Li, Aubrey
2017-07-11 9:41 ` Peter Zijlstra
2017-07-11 16:09 ` Frederic Weisbecker
2017-07-11 16:34 ` Peter Zijlstra
2017-07-11 18:09 ` Paul E. McKenney
2017-07-12 11:54 ` Peter Zijlstra
2017-07-12 15:56 ` Paul E. McKenney
2017-07-12 17:46 ` Peter Zijlstra
2017-07-12 18:53 ` Paul E. McKenney
2017-07-12 19:00 ` Paul E. McKenney
2017-07-19 13:43 ` Frederic Weisbecker
2017-07-19 14:51 ` Paul E. McKenney
2017-07-12 12:22 ` Peter Zijlstra
2017-07-12 15:54 ` Paul E. McKenney [this message]
2017-07-12 17:17 ` Peter Zijlstra
2017-07-12 17:57 ` Peter Zijlstra
2017-07-12 18:50 ` Paul E. McKenney
2017-07-12 18:46 ` Paul E. McKenney
2017-07-13 8:34 ` Peter Zijlstra
2017-07-12 4:15 ` Li, Aubrey
2017-07-12 8:34 ` Peter Zijlstra
2017-07-12 21:32 ` Andi Kleen
2017-07-13 8:36 ` Peter Zijlstra
2017-07-13 14:48 ` Li, Aubrey
2017-07-13 14:53 ` Peter Zijlstra
2017-07-13 15:13 ` Li, Aubrey
2017-07-13 18:28 ` Peter Zijlstra
2017-07-14 3:56 ` Li, Aubrey
2017-07-14 15:38 ` Peter Zijlstra
2017-07-14 15:52 ` Arjan van de Ven
2017-07-14 15:58 ` Peter Zijlstra
2017-07-14 16:03 ` Andi Kleen
2017-07-17 9:21 ` Peter Zijlstra
2017-07-17 13:41 ` Li, Aubrey
2017-07-14 15:53 ` Andi Kleen
2017-07-14 16:06 ` Peter Zijlstra
2017-07-14 16:26 ` Andi Kleen
2017-07-17 19:23 ` Peter Zijlstra
2017-07-17 19:27 ` Arjan van de Ven
2017-07-17 19:46 ` Thomas Gleixner
2017-07-17 19:51 ` Arjan van de Ven
2017-07-17 19:59 ` Thomas Gleixner
2017-07-17 19:48 ` Arjan van de Ven
2017-07-17 19:53 ` Thomas Gleixner
2017-07-17 19:55 ` Arjan van de Ven
2017-07-18 3:23 ` Li, Aubrey
2017-07-18 18:55 ` Peter Zijlstra
2017-07-18 3:14 ` Li, Aubrey
2017-07-18 4:45 ` Andi Kleen
2017-07-18 6:43 ` Thomas Gleixner
2017-07-18 6:56 ` Li, Aubrey
2017-07-18 15:20 ` Paul E. McKenney
2017-07-18 15:29 ` Arjan van de Ven
2017-07-18 16:36 ` Peter Zijlstra
2017-07-18 16:37 ` Arjan van de Ven
2017-07-18 17:05 ` Peter Zijlstra
2017-07-19 5:44 ` Li, Aubrey
2017-07-19 14:48 ` Paul E. McKenney
2017-07-19 15:03 ` Christopher Lameter
2017-07-19 16:54 ` Paul E. McKenney
2017-07-20 1:40 ` Li, Aubrey
2017-07-20 12:50 ` Paul E. McKenney
2017-07-20 13:45 ` Arjan van de Ven
2017-07-20 14:19 ` Peter Zijlstra
2017-07-20 16:02 ` Paul E. McKenney
2017-07-18 16:45 ` Peter Zijlstra
2017-07-18 6:59 ` Andi Kleen
2017-07-18 7:19 ` Thomas Gleixner
2017-07-19 6:12 ` Li, Aubrey
2017-07-19 7:55 ` Thomas Gleixner
2017-07-20 1:56 ` Li, Aubrey
2017-07-20 8:11 ` Thomas Gleixner
2017-07-20 13:48 ` Arjan van de Ven
2017-07-18 7:24 ` Thomas Gleixner
2017-07-18 13:23 ` Peter Zijlstra
2017-07-19 13:43 ` Peter Zijlstra
2017-07-13 15:20 ` Paul E. McKenney
2017-07-14 3:47 ` Li, Aubrey
2017-07-14 4:05 ` Paul E. McKenney
2017-07-17 13:24 ` Li, Aubrey
2017-07-17 13:58 ` Peter Zijlstra
2017-07-17 14:02 ` Li, Aubrey
2017-07-12 12:14 ` Peter Zijlstra
2017-07-11 17:58 ` Christoph Lameter
2017-07-12 2:07 ` Li, Aubrey
2017-07-12 2:35 ` Li, Aubrey
2017-07-12 18:10 ` Peter Zijlstra
2017-07-11 9:02 ` Peter Zijlstra
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