From: Luiz Capitulino <lcapitulino@redhat.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Frederic Weisbecker <frederic@kernel.org>,
LKML <linux-kernel@vger.kernel.org>,
Chris Metcalf <cmetcalf@mellanox.com>,
Thomas Gleixner <tglx@linutronix.de>,
Christoph Lameter <cl@linux.com>,
"Paul E . McKenney" <paulmck@linux.vnet.ibm.com>,
Ingo Molnar <mingo@kernel.org>, Wanpeng Li <kernellwp@gmail.com>,
Mike Galbraith <efault@gmx.de>, Rik van Riel <riel@redhat.com>
Subject: Re: [PATCH 4/5] sched/isolation: Residual 1Hz scheduler tick offload
Date: Tue, 19 Dec 2017 09:34:35 -0500 [thread overview]
Message-ID: <20171219093435.43c863a3@redhat.com> (raw)
In-Reply-To: <20171219091911.tg2k4w7mgv2bcmeb@hirez.programming.kicks-ass.net>
On Tue, 19 Dec 2017 10:19:11 +0100
Peter Zijlstra <peterz@infradead.org> wrote:
> On Tue, Dec 19, 2017 at 04:23:57AM +0100, Frederic Weisbecker wrote:
> > When a CPU runs in full dynticks mode, a 1Hz tick remains in order to
> > keep the scheduler stats alive. However this residual tick is a burden
> > for Real-Time tasks that can't stand no interruption at all.
>
> I'm not sure that is accurate. RT doesn't necessarily have anything much
> to so with this. The tick is per definition very deterministic and thus
> should not be a problem.
What Frederic says is certainly true for HPC. But even for RT I'd say
this is a very nice feature, since it may reduce maximum latency.
next prev parent reply other threads:[~2017-12-19 14:34 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-12-19 3:23 [RFC PATCH 0/5] isolation: 1Hz residual tick offloading Frederic Weisbecker
2017-12-19 3:23 ` [PATCH 1/5] sched: Move tick code to a separate file Frederic Weisbecker
2017-12-19 9:08 ` Peter Zijlstra
2017-12-19 16:33 ` Frederic Weisbecker
2017-12-19 3:23 ` [PATCH 2/5] sched: Rename init_rq_hrtick to hrtick_rq_init Frederic Weisbecker
2017-12-19 3:23 ` [PATCH 3/5] sched/isolation: Add scheduler tick offloading interface Frederic Weisbecker
2017-12-19 3:23 ` [PATCH 4/5] sched/isolation: Residual 1Hz scheduler tick offload Frederic Weisbecker
2017-12-19 9:19 ` Peter Zijlstra
2017-12-19 14:34 ` Luiz Capitulino [this message]
2017-12-19 16:01 ` Christopher Lameter
2017-12-19 16:04 ` Peter Zijlstra
2017-12-19 16:38 ` Christopher Lameter
2017-12-19 16:49 ` Peter Zijlstra
2017-12-19 17:26 ` Christopher Lameter
2017-12-19 16:26 ` Frederic Weisbecker
2017-12-19 16:03 ` Christopher Lameter
2017-12-19 16:32 ` Frederic Weisbecker
2017-12-19 17:23 ` Christopher Lameter
2017-12-19 3:23 ` [PATCH 5/5] sched/isolation: Document "nohz_offload" flag Frederic Weisbecker
-- strict thread matches above, loose matches on Subject: below --
2017-12-21 17:14 [PATCH 0/5] isolation: 1Hz residual tick offloading v2 Frederic Weisbecker
2017-12-21 17:14 ` [PATCH 4/5] sched/isolation: Residual 1Hz scheduler tick offload Frederic Weisbecker
2017-12-30 3:55 [PATCH 0/5] isolation: 1Hz residual tick offloading v3 Frederic Weisbecker
2017-12-30 3:55 ` [PATCH 4/5] sched/isolation: Residual 1Hz scheduler tick offload Frederic Weisbecker
2018-01-04 4:25 [GIT PULL] isolation: 1Hz residual tick offloading v3 Frederic Weisbecker
2018-01-04 4:25 ` [PATCH 4/5] sched/isolation: Residual 1Hz scheduler tick offload Frederic Weisbecker
2018-01-12 19:22 ` Luiz Capitulino
2018-01-16 15:57 ` Frederic Weisbecker
2018-01-16 16:53 ` Luiz Capitulino
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=20171219093435.43c863a3@redhat.com \
--to=lcapitulino@redhat.com \
--cc=cl@linux.com \
--cc=cmetcalf@mellanox.com \
--cc=efault@gmx.de \
--cc=frederic@kernel.org \
--cc=kernellwp@gmail.com \
--cc=linux-kernel@vger.kernel.org \
--cc=mingo@kernel.org \
--cc=paulmck@linux.vnet.ibm.com \
--cc=peterz@infradead.org \
--cc=riel@redhat.com \
--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 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.