From: Andi Kleen <ak@linux.intel.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: 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,
paulmck@linux.vnet.ibm.com, yang.zhang.wz@gmail.com,
x86@kernel.org, linux-kernel@vger.kernel.org,
Aubrey Li <aubrey.li@linux.intel.com>
Subject: Re: [RFC PATCH v1 00/11] Create fast idle path for short idle periods
Date: Mon, 10 Jul 2017 07:46:09 -0700 [thread overview]
Message-ID: <20170710144609.GD31832@tassilo.jf.intel.com> (raw)
In-Reply-To: <20170710084647.zs6wkl3fumszd33g@hirez.programming.kicks-ass.net>
On Mon, Jul 10, 2017 at 10:46:47AM +0200, Peter Zijlstra wrote:
> On Mon, Jul 10, 2017 at 09:38:30AM +0800, Aubrey Li wrote:
> > We measured 3%~5% improvemnt in disk IO workload, and 8%~20% improvement in
> > network workload.
>
> Argh, what a mess :/
The mess is really the current idle entry path. People keep putting more
and more slow stuff there, not realizing it's really a critical fast path.
>
> So how much of the gain is simply due to skipping NOHZ? Mike used to
> carry a patch that would throttle NOHZ. And that is a _far_ smaller and
> simpler patch to do.
Have you ever looked at a ftrace or PT trace of the idle entry?
There's just too much stuff going on there. NOHZ is just the tip
of the iceberg.
-Andi
next prev parent reply other threads:[~2017-07-10 14:46 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 [this message]
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
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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