From: Frederic Weisbecker <fweisbec@gmail.com>
To: Christoph Lameter <cl@linux.com>
Cc: Thomas Gleixner <tglx@linutronix.de>,
Peter Zijlstra <peterz@infradead.org>,
LKML <linux-kernel@vger.kernel.org>,
Byungchul Park <byungchul.park@lge.com>,
Chris Metcalf <cmetcalf@ezchip.com>,
Luiz Capitulino <lcapitulino@redhat.com>,
"Paul E . McKenney" <paulmck@linux.vnet.ibm.com>,
Mike Galbraith <efault@gmx.de>, Rik van Riel <riel@redhat.com>
Subject: Re: [RFC PATCH 4/4] sched: Upload nohz full CPU load on task enqueue/dequeue
Date: Wed, 20 Jan 2016 17:52:23 +0100 [thread overview]
Message-ID: <20160120165222.GE24537@lerouge> (raw)
In-Reply-To: <alpine.DEB.2.20.1601200915170.21490@east.gentwo.org>
On Wed, Jan 20, 2016 at 09:19:36AM -0600, Christoph Lameter wrote:
> On Wed, 20 Jan 2016, Thomas Gleixner wrote:
>
> > > If the user makes use of full dynticks for soft isolation (for performance,
> > > can live with a few interrupts...), there can be short moments of
> > > multitasking.
>
> "Soft" isolation? Like soft realtime ... Argh... Please stay away from
> corrupting the intents of the nohz full mode.
Well some people, especially real time, want no disturbance at all because
their workload really depends on that.
Some other (HPC) don't care about little disturbance.
Although HPC users didn't declare themselves yet, the real time case
expect some more sacrifices (see nohz tasks patchset).
>
> > Again, you are trying to make the second step after the first one is
> > completed. We do not even have proper accounting when we have the ONE task
> > 100% case and still you try to solve problems beyond that.
>
> Please lets only deal with the one task issue. I can have "soft" isolation
> today by moving daemons etc off certain processors. We want definitely to
> run nothing else on the processor and will want to even go further with
> the cache allocation techniques in recent processor to limit the cache
> disturbances from other processors etc etc.
One task is common to all usecases anyway.
next prev parent reply other threads:[~2016-01-20 16:52 UTC|newest]
Thread overview: 58+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-01-13 16:01 [RFC PATCH 0/4] sched: Improve cpu load accounting with nohz Frederic Weisbecker
2016-01-13 16:01 ` [PATCH 1/4] sched: Don't account tickless CPU load on tick Frederic Weisbecker
2016-01-19 13:08 ` Peter Zijlstra
2016-01-19 16:22 ` Frederic Weisbecker
2016-01-19 18:56 ` Peter Zijlstra
2016-01-19 22:33 ` Frederic Weisbecker
2016-01-20 5:43 ` Byungchul Park
2016-01-20 10:26 ` Byungchul Park
2016-01-28 16:01 ` Frederic Weisbecker
2016-01-29 9:50 ` Peter Zijlstra
2016-02-01 10:05 ` Byungchul Park
2016-02-01 10:09 ` [PATCH] sched: calculate sched_clock_cpu without tick handling during nohz Byungchul Park
2016-02-01 10:34 ` [PATCH 1/4] sched: Don't account tickless CPU load on tick Peter Zijlstra
2016-02-01 23:51 ` Byungchul Park
2016-02-02 0:50 ` Byungchul Park
2016-02-01 6:33 ` Byungchul Park
2016-01-20 8:42 ` Thomas Gleixner
2016-01-20 17:36 ` Frederic Weisbecker
2016-01-22 8:40 ` Byungchul Park
2016-01-13 16:01 ` [PATCH 2/4] sched: Consolidate nohz CPU load update code Frederic Weisbecker
2016-01-14 2:30 ` Byungchul Park
2016-01-19 13:13 ` Peter Zijlstra
2016-01-20 0:51 ` Byungchul Park
2016-01-14 5:18 ` Byungchul Park
2016-01-19 13:13 ` Peter Zijlstra
2016-01-19 16:49 ` Frederic Weisbecker
2016-01-20 1:41 ` Byungchul Park
2016-02-29 11:14 ` [tip:sched/core] sched/fair: " tip-bot for Frederic Weisbecker
2016-01-13 16:01 ` [RFC PATCH 3/4] sched: Move cpu load stats functions above fair queue callbacks Frederic Weisbecker
2016-01-13 16:01 ` [RFC PATCH 4/4] sched: Upload nohz full CPU load on task enqueue/dequeue Frederic Weisbecker
2016-01-19 13:17 ` Peter Zijlstra
2016-01-19 17:03 ` Frederic Weisbecker
2016-01-20 9:09 ` Peter Zijlstra
2016-01-20 14:54 ` Frederic Weisbecker
2016-01-20 15:11 ` Thomas Gleixner
2016-01-20 15:19 ` Christoph Lameter
2016-01-20 16:52 ` Frederic Weisbecker [this message]
2016-01-20 16:45 ` Frederic Weisbecker
2016-01-20 16:56 ` Peter Zijlstra
2016-01-20 17:21 ` Frederic Weisbecker
2016-01-20 18:25 ` Peter Zijlstra
2016-01-21 13:25 ` Frederic Weisbecker
2016-01-20 9:03 ` Thomas Gleixner
2016-01-20 14:31 ` Frederic Weisbecker
2016-01-20 14:43 ` Thomas Gleixner
2016-01-20 16:40 ` Frederic Weisbecker
2016-01-20 16:42 ` Christoph Lameter
2016-01-20 16:47 ` Frederic Weisbecker
2016-01-14 21:19 ` [RFC PATCH 0/4] sched: Improve cpu load accounting with nohz Dietmar Eggemann
2016-01-14 21:27 ` Peter Zijlstra
2016-01-14 22:23 ` Dietmar Eggemann
2016-01-15 7:07 ` Byungchul Park
2016-01-15 16:56 ` Dietmar Eggemann
2016-01-18 0:23 ` Byungchul Park
2016-01-19 13:04 ` Peter Zijlstra
2016-01-20 0:48 ` Byungchul Park
2016-01-20 13:04 ` Dietmar Eggemann
2016-02-29 11:14 ` [tip:sched/core] sched/fair: Avoid using decay_load_missed() with a negative value tip-bot for Byungchul Park
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