kern.hz="100" stops high-pitched whine

Chuck Swiger cswiger at
Mon Jul 2 16:51:32 UTC 2007

Jack Stone wrote:
[ ... ]
> A while ago, I noticed someone's kernel config that included:
> hertz=2000 which made me wonder where this setting info comes from?
> I've been using hertz=1000 however, with my much faster boxes, is this 
> appropriate now?

It depends on what you are doing: it is most useful to tune HZ higher when 
machines are being used as firewalls/routers and/or are using device polling. 
  Faster HZ rates cause greater system overhead but will give shorter latency, 
up to a limiting point.

In simpler words, tuning HZ too high is bad.  :-)
One needs to do measurements and tune appropriately.


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