From: Arjan van de Ven <arjan@linux.intel.com>
To: Steven Rostedt <rostedt@goodmis.org>
Cc: paulmck@linux.vnet.ibm.com,
Frederic Weisbecker <fweisbec@gmail.com>,
Rob Landley <rob@landley.net>,
linux-kernel@vger.kernel.org, josh@joshtriplett.org,
zhong@linux.vnet.ibm.com, khilman@linaro.org,
geoff@infradead.org, tglx@linutronix.de
Subject: Re: [PATCH] nohz1: Documentation
Date: Thu, 21 Mar 2013 08:45:07 -0700 [thread overview]
Message-ID: <514B2B03.4030301@linux.intel.com> (raw)
In-Reply-To: <1363825631.6345.45.camel@gandalf.local.home>
On 3/20/2013 5:27 PM, Steven Rostedt wrote:
> I'm not sure I would recommend idle=poll either. It would certainly
> work, but it goes to the other extreme. You think NO_HZ=n drains a
> battery? Try idle=poll.
do not ever use idle=poll on anything production.. really bad idea.
if you temporary cannot cope with the latency, you can use the PMQOS system
to limit (including going all the way to idle=poll).
but using idle=poll completely is very nasty for the hardware.
In addition we should document that idle=poll will cost you peak performance,
possibly quite a bit.
the same is true for the kernel paramter to some extend; it's there to work around
broken bioses/hardware/etc; if you have a latency/runtime requirement, it's much better
to use PMQOS for this from userspace.
next prev parent reply other threads:[~2013-03-21 15:45 UTC|newest]
Thread overview: 43+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-03-18 16:29 [PATCH] nohz1: Documentation Paul E. McKenney
2013-03-18 18:13 ` Rob Landley
2013-03-18 18:46 ` Frederic Weisbecker
2013-03-18 19:59 ` Rob Landley
2013-03-18 20:48 ` Frederic Weisbecker
2013-03-18 22:25 ` Paul E. McKenney
2013-03-20 23:32 ` Steven Rostedt
2013-03-20 23:55 ` Paul E. McKenney
2013-03-21 0:27 ` Steven Rostedt
2013-03-21 2:22 ` Paul E. McKenney
2013-03-21 10:16 ` Borislav Petkov
2013-03-21 15:18 ` Paul E. McKenney
2013-03-21 16:00 ` Borislav Petkov
2013-03-21 15:45 ` Arjan van de Ven [this message]
2013-03-21 17:18 ` Paul E. McKenney
2013-03-21 17:41 ` Arjan van de Ven
2013-03-21 18:02 ` Paul E. McKenney
2013-03-22 18:37 ` Kevin Hilman
2013-03-22 19:25 ` Paul E. McKenney
2013-03-22 4:59 ` Rob Landley
2013-03-21 18:01 ` Frederic Weisbecker
2013-03-21 18:26 ` Paul E. McKenney
2013-03-21 16:08 ` Christoph Lameter
2013-03-21 17:15 ` Paul E. McKenney
2013-03-21 18:39 ` Christoph Lameter
2013-03-21 18:58 ` Paul E. McKenney
2013-03-21 20:04 ` Christoph Lameter
2013-03-21 20:42 ` Frederic Weisbecker
2013-03-21 21:02 ` Christoph Lameter
2013-03-21 21:06 ` Frederic Weisbecker
2013-03-21 20:50 ` Paul E. McKenney
2013-03-22 14:38 ` Christoph Lameter
2013-03-22 16:28 ` Paul E. McKenney
2013-03-25 14:31 ` Christoph Lameter
2013-03-25 14:37 ` Frederic Weisbecker
2013-03-25 15:18 ` Christoph Lameter
2013-03-25 15:20 ` Frederic Weisbecker
2013-03-22 9:52 ` Mats Liljegren
2013-03-22 19:01 ` Kevin Hilman
2013-03-21 18:44 ` Steven Rostedt
2013-03-21 18:53 ` Christoph Lameter
2013-03-21 19:16 ` Steven Rostedt
2013-03-21 18:59 ` Paul E. McKenney
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