Re: [PATCH] nohz1: Documentation

[Arjan van de Ven]

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.

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