From: Daniel Bristot de Oliveira <bristot@redhat.com>
To: Peter Zijlstra <peterz@infradead.org>,
Atul Kumar Pant <quic_atulpant@quicinc.com>
Cc: mingo@redhat.com, juri.lelli@redhat.com,
vincent.guittot@linaro.org, dietmar.eggemann@arm.com,
rostedt@goodmis.org, bsegall@google.com, mgorman@suse.de,
vschneid@redhat.com, rafael@kernel.org,
daniel.lezcano@linaro.org, kernel@quicinc.com,
linux-kernel@vger.kernel.org, linux-pm@vger.kernel.org
Subject: Re: [RFC PATCH 0/2] Disable RT-throttling for idle-inject threads
Date: Wed, 10 Apr 2024 14:24:14 +0200 [thread overview]
Message-ID: <88144494-33f1-4f43-88c0-885ea6b87e07@redhat.com> (raw)
In-Reply-To: <20240410114609.GA40213@noisy.programming.kicks-ass.net>
On 4/10/24 13:46, Peter Zijlstra wrote:
> Also, we'll be replacing the throttling code with DL servers 'soonish'
> at which point all this will stop working anyway, since DL will preempt
> anything FIFO, including your idle injection crud.
+1
also, given that the code spins with preempt disabled, with dl server it could
even become a non-rt thread...
FIFO RUNNING
DL_SERVER activates
their loop
disables preemption()
run()
enable preemption()
DL_SERVE throttled
FIFO BACK
So, there will be no need for this busy loop to be RT.
Anyways, it breaks RT and DL if it keeps running for too long... It can
also cause complaints like RCU stalls and loong wait on locks, e.g., on
kworkers...
-- Daniel
next prev parent reply other threads:[~2024-04-10 12:24 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-04-10 4:54 Atul Pant
2024-04-10 4:54 ` [RFC PATCH 1/2] sched/rt: Disable runtime accounting for idle threads with SCHED_FIFO policy Atul Pant
2024-04-10 7:00 ` Daniel Bristot de Oliveira
2024-04-10 4:54 ` [RFC PATCH 2/2] sched/idle: Add a description for play_idle_precise Atul Pant
2024-04-10 8:54 ` [RFC PATCH 0/2] Disable RT-throttling for idle-inject threads Peter Zijlstra
2024-04-10 11:29 ` Atul Kumar Pant
2024-04-10 11:46 ` Peter Zijlstra
2024-04-10 12:24 ` Daniel Bristot de Oliveira [this message]
2024-04-10 13:29 ` Vincent Guittot
2024-04-10 13:31 ` Steven Rostedt
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=88144494-33f1-4f43-88c0-885ea6b87e07@redhat.com \
--to=bristot@redhat.com \
--cc=bsegall@google.com \
--cc=daniel.lezcano@linaro.org \
--cc=dietmar.eggemann@arm.com \
--cc=juri.lelli@redhat.com \
--cc=kernel@quicinc.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-pm@vger.kernel.org \
--cc=mgorman@suse.de \
--cc=mingo@redhat.com \
--cc=peterz@infradead.org \
--cc=quic_atulpant@quicinc.com \
--cc=rafael@kernel.org \
--cc=rostedt@goodmis.org \
--cc=vincent.guittot@linaro.org \
--cc=vschneid@redhat.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox
all inboxes | Powered by JetHome®