From: Rob Landley <rob@landley.net>
To: Arjan van de Ven <arjan@linux.intel.com>
Cc: Steven Rostedt <rostedt@goodmis.org>,
paulmck@linux.vnet.ibm.com,
Frederic Weisbecker <fweisbec@gmail.com>,
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 23:59:50 -0500 [thread overview]
Message-ID: <1363928390.15703.57@driftwood> (raw)
In-Reply-To: <514B2B03.4030301@linux.intel.com> (from arjan@linux.intel.com on Thu Mar 21 10:45:07 2013)
On 03/21/2013 10:45:07 AM, Arjan van de Ven wrote:
> 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.
Where should that be documented?
> 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.
I googled and found
http://elinux.org/images/f/f9/Elc2008_pm_qos_slides.pdf
Rob
next prev parent reply other threads:[~2013-03-22 4:59 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
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 [this message]
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
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=1363928390.15703.57@driftwood \
--to=rob@landley.net \
--cc=arjan@linux.intel.com \
--cc=fweisbec@gmail.com \
--cc=geoff@infradead.org \
--cc=josh@joshtriplett.org \
--cc=khilman@linaro.org \
--cc=linux-kernel@vger.kernel.org \
--cc=paulmck@linux.vnet.ibm.com \
--cc=rostedt@goodmis.org \
--cc=tglx@linutronix.de \
--cc=zhong@linux.vnet.ibm.com \
/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 a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox