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SubjectRe: [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

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