From: Peter Zijlstra <peterz@infradead.org>
To: Ingo Molnar <mingo@kernel.org>
Cc: Frederic Weisbecker <frederic@kernel.org>,
LKML <linux-kernel@vger.kernel.org>,
Jacek Anaszewski <jacek.anaszewski@gmail.com>,
Wanpeng Li <wanpengli@tencent.com>,
"Rafael J . Wysocki" <rjw@rjwysocki.net>,
Benjamin Herrenschmidt <benh@kernel.crashing.org>,
Rik van Riel <riel@surriel.com>,
Thomas Gleixner <tglx@linutronix.de>,
Yauheni Kaliuta <yauheni.kaliuta@redhat.com>,
Viresh Kumar <viresh.kumar@linaro.org>,
Pavel Machek <pavel@ucw.cz>
Subject: Re: [PATCH 1/6] sched/cputime: Support other fields on kcpustat_field()
Date: Wed, 20 Nov 2019 22:04:40 +0100 [thread overview]
Message-ID: <20191120210440.GR3079@worktop.programming.kicks-ass.net> (raw)
In-Reply-To: <20191120115142.GA89662@gmail.com>
On Wed, Nov 20, 2019 at 12:51:42PM +0100, Ingo Molnar wrote:
> * Frederic Weisbecker <frederic@kernel.org> wrote:
> > + /*
> > + * Nice VS unnice cputime accounting may be inaccurate if
> > + * the nice value has changed since the last vtime update.
> > + * But proper fix would involve interrupting target on nice
> > + * updates which is a no go on nohz_full.
>
> Well, we actually already interrupt the target in both sys_nice() and
> sys_setpriority() etc. syscall variants: we call set_user_nice() which
> calls resched_curr() and the task is sent an IPI and runs through a
> reschedule.
I think we can easily avoid doing that IPI when we find it is the only
task on that runqueue. Which is exactly the case for NOHZ_FULL.
next prev parent reply other threads:[~2019-11-20 21:05 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-11-19 23:22 [PATCH 0/6] sched/nohz: Make the rest of kcpustat vtime aware v2 Frederic Weisbecker
2019-11-19 23:22 ` [PATCH 1/6] sched/cputime: Support other fields on kcpustat_field() Frederic Weisbecker
2019-11-20 11:51 ` Ingo Molnar
2019-11-20 21:04 ` Peter Zijlstra [this message]
2019-11-19 23:22 ` [PATCH 2/6] sched/vtime: Bring all-in-one kcpustat accessor for vtime fields Frederic Weisbecker
2019-11-20 12:04 ` Ingo Molnar
2019-11-20 15:00 ` Frederic Weisbecker
2019-11-19 23:22 ` [PATCH 3/6] procfs: Use all-in-one vtime aware kcpustat accessor Frederic Weisbecker
2019-11-19 23:22 ` [PATCH 4/6] cpufreq: Use vtime aware kcpustat accessors for user time Frederic Weisbecker
2019-11-19 23:22 ` [PATCH 5/6] leds: Use all-in-one vtime aware kcpustat accessor Frederic Weisbecker
2019-11-19 23:22 ` [PATCH 6/6] rackmeter: Use " Frederic Weisbecker
-- strict thread matches above, loose matches on Subject: below --
2019-11-21 2:44 [PATCH 0/6] sched/nohz: Make the rest of kcpustat vtime aware v3 Frederic Weisbecker
2019-11-21 2:44 ` [PATCH 1/6] sched/cputime: Support other fields on kcpustat_field() Frederic Weisbecker
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=20191120210440.GR3079@worktop.programming.kicks-ass.net \
--to=peterz@infradead.org \
--cc=benh@kernel.crashing.org \
--cc=frederic@kernel.org \
--cc=jacek.anaszewski@gmail.com \
--cc=linux-kernel@vger.kernel.org \
--cc=mingo@kernel.org \
--cc=pavel@ucw.cz \
--cc=riel@surriel.com \
--cc=rjw@rjwysocki.net \
--cc=tglx@linutronix.de \
--cc=viresh.kumar@linaro.org \
--cc=wanpengli@tencent.com \
--cc=yauheni.kaliuta@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 an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.