From: "Rafael J. Wysocki" <rjw@rjwysocki.net>
To: Jens Axboe <axboe@kernel.dk>, Peter Zijlstra <peterz@infradead.org>
Cc: linux-kernel@vger.kernel.org, tglx@linutronix.de,
linux-pm@vger.kernel.org, daniel.lezcano@linaro.org,
"Rafael J. Wysocki" <rafael@kernel.org>
Subject: Re: [PATCH 4/4] sched/core: split iowait state into two states
Date: Thu, 25 Apr 2024 16:20:29 +0200 [thread overview]
Message-ID: <8409301.NyiUUSuA9g@kreacher> (raw)
In-Reply-To: <20240424100127.GV40213@noisy.programming.kicks-ass.net>
On Wednesday, April 24, 2024 12:01:27 PM CEST Peter Zijlstra wrote:
> On Tue, Apr 16, 2024 at 06:11:21AM -0600, Jens Axboe wrote:
> > iowait is a bogus metric, but it's helpful in the sense that it allows
> > short waits to not enter sleep states that have a higher exit latency
> > than would've otherwise have been picked for iowait'ing tasks. However,
> > it's harmless in that lots of applications and monitoring assumes that
> > iowait is busy time, or otherwise use it as a health metric.
> > Particularly for async IO it's entirely nonsensical.
>
> Let me get this straight, all of this is about working around
> cpuidle menu governor insaity?
>
> Rafael, how far along are we with fully deprecating that thing? Yes it
> still exists, but should people really be using it still?
Well, they appear to be used to it ...
prev parent reply other threads:[~2024-04-25 14:20 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20240416121526.67022-1-axboe@kernel.dk>
[not found] ` <20240416121526.67022-5-axboe@kernel.dk>
2024-04-24 10:01 ` [PATCH 4/4] sched/core: split iowait state into two states Peter Zijlstra
2024-04-24 10:08 ` Christian Loehle
2024-04-25 10:16 ` Peter Zijlstra
2024-04-25 10:39 ` Christian Loehle
2024-04-25 14:20 ` Rafael J. Wysocki [this message]
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=8409301.NyiUUSuA9g@kreacher \
--to=rjw@rjwysocki.net \
--cc=axboe@kernel.dk \
--cc=daniel.lezcano@linaro.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-pm@vger.kernel.org \
--cc=peterz@infradead.org \
--cc=rafael@kernel.org \
--cc=tglx@linutronix.de \
/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;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).