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
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
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