From: "Rafael J. Wysocki" <rjw@rjwysocki.net>
To: Julia Lawall <julia.lawall@inria.fr>
Cc: Peter Zijlstra <peterz@infradead.org>,
Mel Gorman <mgorman@suse.de>, Ingo Molnar <mingo@redhat.com>,
kernel-janitors@vger.kernel.org,
Juri Lelli <juri.lelli@redhat.com>,
Vincent Guittot <vincent.guittot@linaro.org>,
Dietmar Eggemann <dietmar.eggemann@arm.com>,
Steven Rostedt <rostedt@goodmis.org>,
Ben Segall <bsegall@google.com>,
Daniel Bristot de Oliveira <bristot@redhat.com>,
linux-kernel@vger.kernel.org,
Valentin Schneider <valentin.schneider@arm.com>,
Gilles Muller <Gilles.Muller@inria.fr>,
viresh.kumar@linaro.org, srinivas.pandruvada@linux.intel.com
Subject: Re: [PATCH] sched/fair: check for idle core
Date: Wed, 21 Oct 2020 20:15:47 +0200 [thread overview]
Message-ID: <20581608.8Dxr8OdOFj@kreacher> (raw)
In-Reply-To: <alpine.DEB.2.22.394.2010211422230.8475@hadrien>
On Wednesday, October 21, 2020 2:42:20 PM CEST Julia Lawall wrote:
>
> On Wed, 21 Oct 2020, Peter Zijlstra wrote:
>
> > On Wed, Oct 21, 2020 at 01:56:55PM +0200, Julia Lawall wrote:
> > > Prior to 5.8, my machine was using intel_pstate and had few background
> > > tasks. Thus the problem wasn't visible in practice. Starting with 5.8
> > > the kernel decided that intel_cpufreq would be more appropriate, which
> > > introduced kworkers every 0.004 seconds on all cores.
> >
> > That still doesn't make any sense. Are you running the legacy on-demand
> > thing or something?
> >
> > Rafael, Srinivas, Viresh, how come it defaults to that?
>
> The relevant commits are 33aa46f252c7, and 39a188b88332 that fixes a small
> bug. I have a Intel(R) Xeon(R) CPU E7-8870 v4 @ 2.10GHz that does not
> have the HWP feature, even though the cores seemed to be able to change
> their frequencies at the hardware level.
That's in the range of "turbo" P-states (if a P-state above a certain threshold
is requested by the governor, the processor has a license to choose P-states
in the range above this threshold by itself).
Cheers!
next prev parent reply other threads:[~2020-10-21 18:15 UTC|newest]
Thread overview: 69+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-20 16:37 [PATCH] sched/fair: check for idle core Julia Lawall
2020-10-21 7:29 ` Vincent Guittot
2020-10-21 11:13 ` Peter Zijlstra
2020-10-21 12:27 ` Vincent Guittot
2020-10-21 11:20 ` Mel Gorman
2020-10-21 11:56 ` Julia Lawall
2020-10-21 12:19 ` Peter Zijlstra
2020-10-21 12:42 ` Julia Lawall
2020-10-21 12:52 ` Peter Zijlstra
2020-10-21 13:43 ` Julia Lawall
2020-10-21 18:18 ` Rafael J. Wysocki
2020-10-21 18:15 ` Rafael J. Wysocki [this message]
2020-10-21 19:47 ` Julia Lawall
2020-10-21 20:25 ` Rafael J. Wysocki
2020-10-21 13:10 ` Peter Zijlstra
2020-10-21 18:11 ` Rafael J. Wysocki
2020-10-22 4:41 ` Viresh Kumar
2020-10-22 7:11 ` Peter Zijlstra
2020-10-22 10:47 ` Viresh Kumar
2020-10-22 11:45 ` Rafael J. Wysocki
2020-10-22 12:02 ` default cpufreq gov, was: " Peter Zijlstra
2020-10-22 12:19 ` Rafael J. Wysocki
2020-10-22 12:29 ` Peter Zijlstra
2020-10-22 14:52 ` Mel Gorman
2020-10-22 14:58 ` Colin Ian King
2020-10-22 15:12 ` Phil Auld
2020-10-22 16:35 ` Mel Gorman
2020-10-22 17:59 ` Rafael J. Wysocki
2020-10-22 20:32 ` Mel Gorman
2020-10-22 20:39 ` Phil Auld
2020-10-22 15:25 ` Peter Zijlstra
2020-10-22 15:55 ` Rafael J. Wysocki
2020-10-22 16:29 ` Mel Gorman
2020-10-22 20:10 ` Giovanni Gherdovich
2020-10-22 20:16 ` Giovanni Gherdovich
2020-10-23 7:03 ` Peter Zijlstra
2020-10-23 17:46 ` Tom Lendacky
2020-10-26 19:52 ` Fontenot, Nathan
2020-10-22 15:45 ` A L
2020-10-22 15:55 ` Vincent Guittot
2020-10-23 5:11 ` Viresh Kumar
2020-10-22 16:23 ` [PATCH] cpufreq: Avoid configuring old governors as default with intel_pstate Rafael J. Wysocki
2020-10-23 6:17 ` Viresh Kumar
2020-10-23 11:59 ` Rafael J. Wysocki
2020-10-23 15:15 ` [PATCH v2] " Rafael J. Wysocki
2020-10-27 3:01 ` Viresh Kumar
2020-10-27 11:11 ` default cpufreq gov, was: [PATCH] sched/fair: check for idle core Qais Yousef
2020-10-27 11:26 ` Valentin Schneider
2020-10-27 11:42 ` Qais Yousef
2020-10-27 11:48 ` Viresh Kumar
2020-10-23 6:12 ` Viresh Kumar
2020-10-23 15:06 ` Rafael J. Wysocki
2020-10-27 3:01 ` Viresh Kumar
2020-10-22 11:21 ` AW: " Walter Harms
2020-10-21 12:28 ` Mel Gorman
2020-10-21 12:25 ` Vincent Guittot
2020-10-21 12:47 ` Mel Gorman
2020-10-21 12:56 ` Julia Lawall
2020-10-21 13:18 ` Mel Gorman
2020-10-21 13:24 ` Julia Lawall
2020-10-21 15:08 ` Mel Gorman
2020-10-21 15:18 ` Julia Lawall
2020-10-21 15:23 ` Vincent Guittot
2020-10-21 15:33 ` Julia Lawall
2020-10-21 15:19 ` Vincent Guittot
2020-10-21 17:00 ` Mel Gorman
2020-10-21 17:39 ` Julia Lawall
2020-10-21 13:48 ` Julia Lawall
2020-10-21 15:26 ` Mel Gorman
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