Messages in this thread | | | Date | Thu, 21 Mar 2013 23:59:50 -0500 | From | Rob Landley <> | Subject | Re: [PATCH] nohz1: Documentation |
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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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