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From: Rik van Riel <riel@surriel.com>
To: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Cc: Peter Zijlstra <peterz@infradead.org>,
	Linux PM <linux-pm@vger.kernel.org>,
	Frederic Weisbecker <fweisbec@gmail.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	Paul McKenney <paulmck@linux.vnet.ibm.com>,
	Thomas Ilsche <thomas.ilsche@tu-dresden.de>,
	Doug Smythies <dsmythies@telus.net>,
	Aubrey Li <aubrey.li@linux.intel.com>,
	Mike Galbraith <mgalbraith@suse.de>,
	LKML <linux-kernel@vger.kernel.org>
Subject: Re: [RFT][PATCH v7 0/8] sched/cpuidle: Idle loop rework
Date: Wed, 21 Mar 2018 10:53:58 -0400
Message-ID: <1521644038.6308.18.camel@surriel.com> (raw)
In-Reply-To: <4584935.MPnHlxh7Zu@aspire.rjw.lan>

On Wed, 2018-03-21 at 14:55 +0100, Rafael J. Wysocki wrote:
> On Wednesday, March 21, 2018 1:31:07 PM CET Rik van Riel wrote:
> > On Tue, 2018-03-20 at 16:12 +0100, Rafael J. Wysocki wrote:
> > > Hi All,
> > > 
> > > Thanks a lot for the feedback so far!
> > > 
> > > Respin after recent comments from Peter.
> > > 
> > > Patches [1-3] unmodified since v5, patch 4 is new and the other
> > > ones
> > > have been updated to address feedback.
> > > 
> > > The previous summary that still applies:
> 
> Thanks for the testing!
>  
> > For some reason I see increased CPU utilization
> > with this patch series (75% -> 85%) with the same
> > rate of requests being handled by the vanilla
> > kernel and a kernel with these patches applied.
> > 
> > I am running a bisect in the series to see what
> > change could possibly cause that,
> 
> The first 4 patches in the v7 should not change functionality by
> themselves.
> 
> If you replace the original [5/8] with the v7.2 of it I've just
> posted (https://patchwork.kernel.org/patch/10299429/), then it
> should not change functionality by itself too.
> 
> Then you only have 3 patches to check. :-)

I kicked off a test with your v7.2 series first.
I have the idle poll loop rework in the mix, too.

I will check the last 3 patches bit by bit through
today, and will let you know which causes the issue.

I will also try to figure out what the issue is,
if I can :)

> > and also digging
> > through system statistics to see whether it might
> > be something as perverse as not mistakenly choosing
> > deeper C-states on one core causing other cores to
> > miss out on turbo mode...
> 
> I have no idea ATM.  And what's the workload?

The workload is memcache style, with equal
queries coming in to both the system running
the control kernel, and the system running
the test kernel.

On the control system, CPU utilization is
around 75%, while on the test system it is
up to 85% - for the same number of queries.

-- 
All Rights Reversed.

      reply index

Thread overview: 41+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-03-20 15:12 Rafael J. Wysocki
2018-03-20 15:13 ` [RFT][PATCH v7 1/8] time: tick-sched: Reorganize idle tick management code Rafael J. Wysocki
2018-03-20 15:15 ` [RFT][PATCH v7 2/8] sched: idle: Do not stop the tick upfront in the idle loop Rafael J. Wysocki
2018-03-20 15:15 ` [RFT][PATCH v7 3/8] " Rafael J. Wysocki
2018-03-20 18:00   ` [Correction][RFT][PATCH v7 3/8] sched: idle: Do not stop the tick before cpuidle_idle_call() Rafael J. Wysocki
2018-03-20 15:16 ` [RFT][PATCH v7 4/8] jiffies: Introduce USER_TICK_USEC and redefine TICK_USEC Rafael J. Wysocki
2018-03-20 15:45 ` [RFT][PATCH v7 5/8] cpuidle: Return nohz hint from cpuidle_select() Rafael J. Wysocki
2018-03-21  6:48   ` [RFT][PATCH v7.1 " Rafael J. Wysocki
2018-03-21 11:52     ` Rafael J. Wysocki
2018-03-21 13:03   ` [RFT][PATCH v7.2 " Rafael J. Wysocki
2018-03-21 14:36   ` [RFT][PATCH v7 " Rafael J. Wysocki
2018-03-21 17:59     ` Thomas Ilsche
2018-03-21 22:15       ` Rafael J. Wysocki
2018-03-22 13:18         ` Thomas Ilsche
2018-03-22 17:23           ` Rafael J. Wysocki
2018-03-22  6:24       ` Doug Smythies
2018-03-22 15:41       ` Doug Smythies
2018-03-22 17:21         ` Rafael J. Wysocki
2018-03-21 18:23     ` Doug Smythies
2018-03-22 17:40   ` [RFT][PATCH v7.3 " Rafael J. Wysocki
2018-03-28  9:14     ` Thomas Ilsche
2018-03-30  9:39       ` Rafael J. Wysocki
2018-04-10 15:22         ` Thomas Ilsche
2018-03-22 20:46   ` Doug Smythies
2018-03-20 15:45 ` [RFT][PATCH v7 6/8] sched: idle: Select idle state before stopping the tick Rafael J. Wysocki
2018-03-27 21:50   ` Thomas Ilsche
2018-03-27 22:10     ` Rafael J. Wysocki
2018-03-28  8:13       ` Rafael J. Wysocki
2018-03-28  8:38         ` Thomas Ilsche
2018-03-28 10:37           ` Rafael J. Wysocki
2018-03-28 10:56             ` Rafael J. Wysocki
2018-03-28 15:15               ` Thomas Ilsche
2018-03-28 20:41               ` Doug Smythies
2018-03-28 23:11                 ` Rafael J. Wysocki
2018-03-20 15:46 ` [RFT][PATCH v7 7/8] cpuidle: menu: Refine idle state selection for running tick Rafael J. Wysocki
2018-03-20 15:47 ` [RFT][PATCH v7 8/8] cpuidle: menu: Avoid selecting shallow states with stopped tick Rafael J. Wysocki
2018-03-20 17:52 ` [RFT][PATCH v7 3/8] sched: idle: Do not stop the tick upfront in the idle loop Doug Smythies
2018-03-20 18:01   ` Rafael J. Wysocki
2018-03-21 12:31 ` [RFT][PATCH v7 0/8] sched/cpuidle: Idle loop rework Rik van Riel
2018-03-21 13:55   ` Rafael J. Wysocki
2018-03-21 14:53     ` Rik van Riel [this message]

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