From: Tim Janik <timj@gnu.org>
To: Vincent Guittot <vincent.guittot@linaro.org>
Cc: mingo@redhat.com, peterz@infradead.org, juri.lelli@redhat.com,
dietmar.eggemann@arm.com, rostedt@goodmis.org,
bsegall@google.com, mgorman@suse.de, bristot@redhat.com,
vschneid@redhat.com, linux-kernel@vger.kernel.org,
parth@linux.ibm.com, qais.yousef@arm.com, chris.hyser@oracle.com,
valentin.schneider@arm.com, patrick.bellasi@matbug.net,
David.Laight@aculab.com, pjt@google.com, pavel@ucw.cz,
tj@kernel.org, qperret@google.com, tim.c.chen@linux.intel.com,
joshdon@google.com
Subject: Re: [PATCH v4 4/8] sched/core: Add permission checks for setting the latency_nice value
Date: Tue, 20 Sep 2022 12:18:38 +0200 [thread overview]
Message-ID: <ca9231c6-ef15-959f-f028-e55fbe686699@gnu.org> (raw)
In-Reply-To: <CAKfTPtB8OeRzbDjfKoNUGLC1XUXT07G9QedCJ8stSMGvAD5hNg@mail.gmail.com>
Hi.
On 19.09.22 14:41, Vincent Guittot wrote:
> Hi,
>
> Thanks you for describing in detail your use case.
> Ok, Your explanation makes sense to me especially because we want to
> ensure to not provide more cpu time with this latency prio. I'm
> curious to see the feedback from others about the reason we want
> CAP_SYS_NICE other than following nice priority.
>
> Side question, Have you tried this patchset (minus this patch) with
> your use case ?
I have now tested a modified version of the ALSA Test_latency.c program
that acquires latency nice as non-root:
https://gist.github.com/tim-janik/88f9df5456b879ecc59da93dc6ce6be1
With a busy but not overloaded CPU, the short time latency tests are
often better, measured with: ./lnice-latency -p -s 1
But the results aren't very reliable with this test. I.e. requesting a
latency nice value of -20 reduces the chance for underruns somewhat but
doesn't eliminate them (and lnice-latency.c gives up on the first XRUN
in the given time period). It might be better to instead count the XRUN
occurances over a given time pertiod.
--
Anklang Free Software DAW
https://anklang.testbit.eu/
next prev parent reply other threads:[~2022-09-20 10:18 UTC|newest]
Thread overview: 44+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-09-16 8:02 [PATCH v4 0/8] Add latency priority for CFS class Vincent Guittot
2022-09-16 8:02 ` [PATCH v4 1/8] sched: Introduce latency-nice as a per-task attribute Vincent Guittot
2022-09-16 8:02 ` [PATCH v4 2/8] sched/core: Propagate parent task's latency requirements to the child task Vincent Guittot
2022-09-16 8:03 ` [PATCH v4 3/8] sched: Allow sched_{get,set}attr to change latency_nice of the task Vincent Guittot
2022-09-16 8:03 ` [PATCH v4 4/8] sched/core: Add permission checks for setting the latency_nice value Vincent Guittot
2022-09-19 8:52 ` timj
2022-09-19 8:52 ` timj
2022-09-19 12:41 ` Vincent Guittot
2022-09-20 10:18 ` Tim Janik [this message]
2022-09-20 14:56 ` Vincent Guittot
2022-09-21 16:11 ` Vincent Guittot
2022-09-16 8:03 ` [PATCH v4 5/8] sched/fair: Take into account latency priority at wakeup Vincent Guittot
[not found] ` <20220916120245.2951-1-hdanton@sina.com>
2022-09-16 13:36 ` Vincent Guittot
[not found] ` <20220917225819.817-1-hdanton@sina.com>
2022-09-18 10:46 ` Vincent Guittot
[not found] ` <20220920113238.1176-1-hdanton@sina.com>
2022-09-20 15:17 ` Vincent Guittot
2022-09-19 10:05 ` Dietmar Eggemann
2022-09-19 15:39 ` Vincent Guittot
2022-09-20 13:18 ` Dietmar Eggemann
2022-09-20 15:49 ` Vincent Guittot
2022-09-21 22:41 ` Dietmar Eggemann
2022-09-22 7:12 ` Vincent Guittot
2022-09-22 16:50 ` Dietmar Eggemann
2022-09-23 6:01 ` Vincent Guittot
2022-09-16 8:03 ` [PATCH v4 6/8] sched/fair: Add sched group latency support Vincent Guittot
2022-09-19 11:55 ` Dietmar Eggemann
2022-09-19 15:49 ` Vincent Guittot
2022-09-19 17:34 ` Tejun Heo
2022-09-20 7:03 ` Vincent Guittot
2022-09-21 16:07 ` Qais Yousef
2022-09-21 16:48 ` Tejun Heo
2022-09-21 17:02 ` Vincent Guittot
2022-09-21 17:12 ` Tejun Heo
2022-09-22 6:40 ` Vincent Guittot
2022-09-22 10:49 ` Qais Yousef
2022-09-20 18:17 ` Dietmar Eggemann
2022-09-21 7:48 ` Vincent Guittot
2022-09-19 17:34 ` Tejun Heo
2022-09-20 7:02 ` Vincent Guittot
2022-09-16 8:03 ` [PATCH v4 7/8] sched/core: support latency priority with sched core Vincent Guittot
2022-09-16 8:03 ` [PATCH v4 8/8] sched/fair: Add latency list Vincent Guittot
2022-09-21 16:08 ` [PATCH v4 0/8] Add latency priority for CFS class Qais Yousef
2022-09-22 7:19 ` Vincent Guittot
2022-09-22 11:00 ` Qais Yousef
2022-09-22 13:03 ` Vincent Guittot
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