From: Christopher Lameter <cl@linux.com>
To: Mike Galbraith <efault@gmx.de>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
Frederic Weisbecker <fweisbec@gmail.com>,
Luiz Capitulino <lcapitulino@redhat.com>,
LKML <linux-kernel@vger.kernel.org>,
Peter Zijlstra <peterz@infradead.org>,
Chris Metcalf <cmetcalf@mellanox.com>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@kernel.org>, Rik van Riel <riel@redhat.com>,
Wanpeng Li <kernellwp@gmail.com>
Subject: Re: [RFC PATCH 7/9] housekeeping: Use own boot option, independant from nohz
Date: Tue, 15 Aug 2017 11:26:11 -0500 (CDT) [thread overview]
Message-ID: <alpine.DEB.2.20.1708151122090.2578@nuc-kabylake> (raw)
In-Reply-To: <1502812653.1349.94.camel@gmx.de>
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On Tue, 15 Aug 2017, Mike Galbraith wrote:
> On Tue, 2017-08-15 at 10:52 -0500, Christopher Lameter wrote:
> > On Tue, 15 Aug 2017, Paul E. McKenney wrote:
> >
> > > Don't the HPC guys just disable idle_balance(), or am I out of date again?
> >
> > Ummm.. Why does idle management matter when your goal is to keep all
> > processor busy working at maximum throughput?
>
> If you _never_ idle, you never have to worry about it. Is 100% CPU
> until the end of time all there is to HPC?
Most of the time that is true for HPC loads. They may also go through a
I/O throughput constrained processing phase or synchronization phase where
idle activity occurs.
However, there are also low latency loads that are often confused with
HPC. Those are usually waiting idle until an event happens and then have
to react to it in the fastest way possible. After that they go back to
idle. You could call this a RT load (since the term seems to be so
flexible...) but its more event based than the typical idea of realtime
(do something at this and thata time).
next prev parent reply other threads:[~2017-08-16 13:06 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-07-21 13:21 [RFC PATCH 0/9] Introduce housekeeping subsystem Frederic Weisbecker
2017-07-21 13:21 ` [RFC PATCH 1/9] housekeeping: Move housekeeping related code to its own file Frederic Weisbecker
2017-07-21 13:21 ` [RFC PATCH 2/9] watchdog: Use housekeeping_cpumask() instead of ad-hoc version Frederic Weisbecker
2017-07-21 13:21 ` [RFC PATCH 3/9] housekeeping: Provide a dynamic off-case to housekeeping_any_cpu() Frederic Weisbecker
2017-07-21 13:21 ` [RFC PATCH 4/9] housekeeping: Make housekeeping cpumask private Frederic Weisbecker
2017-07-21 13:21 ` [RFC PATCH 5/9] housekeeping: Use its own static key Frederic Weisbecker
2017-07-21 13:21 ` [RFC PATCH 6/9] housekeeping: Rename is_housekeeping_cpu to housekeeping_cpu Frederic Weisbecker
2017-07-21 13:21 ` [RFC PATCH 7/9] housekeeping: Use own boot option, independant from nohz Frederic Weisbecker
2017-08-11 19:09 ` Luiz Capitulino
2017-08-12 14:10 ` Frederic Weisbecker
2017-08-13 15:13 ` Luiz Capitulino
2017-08-14 17:01 ` Frederic Weisbecker
2017-08-14 17:34 ` Luiz Capitulino
2017-08-14 18:29 ` Mike Galbraith
2017-08-15 13:07 ` Frederic Weisbecker
2017-08-15 15:15 ` Mike Galbraith
2017-08-15 15:30 ` Paul E. McKenney
2017-08-15 15:52 ` Christopher Lameter
2017-08-15 15:57 ` Mike Galbraith
2017-08-15 16:26 ` Christopher Lameter [this message]
2017-08-16 18:00 ` Mike Galbraith
2017-08-15 15:53 ` Mike Galbraith
2017-07-21 13:21 ` [RFC PATCH 8/9] housekeeping: Move it under own config, independant from NO_HZ Frederic Weisbecker
2017-07-21 13:21 ` [RFC PATCH 9/9] workqueue: Affine unbound workqueues to housekeeping cpumask Frederic Weisbecker
2017-07-21 19:48 ` [RFC PATCH 0/9] Introduce housekeeping subsystem Chris Metcalf
2017-08-10 12:54 ` Frederic Weisbecker
2017-08-10 13:57 ` Chris Metcalf
2017-08-11 6:36 ` Mike Galbraith
2017-08-11 15:01 ` Frederic Weisbecker
2017-08-11 19:22 ` Luiz Capitulino
2017-08-11 15:08 ` Chris Metcalf
2017-08-11 15:35 ` Christopher Lameter
2017-08-11 15:50 ` Chris Metcalf
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