linux-kernel - Re: [PATCH] nohz1: Documentation

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <1363928390.15703.57@driftwood>
Date:	Thu, 21 Mar 2013 23:59:50 -0500
From:	Rob Landley <rob@...dley.net>
To:	Arjan van de Ven <arjan@...ux.intel.com>
Cc:	Steven Rostedt <rostedt@...dmis.org>, paulmck@...ux.vnet.ibm.com,
	Frederic Weisbecker <fweisbec@...il.com>,
	linux-kernel@...r.kernel.org, josh@...htriplett.org,
	zhong@...ux.vnet.ibm.com, khilman@...aro.org, geoff@...radead.org,
	tglx@...utronix.de
Subject: Re: [PATCH] nohz1: Documentation

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--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/