Date: Mon, 02 Jul 2007 12:51:23 -0400 From: Chuck Swiger <cswiger@mac.com> To: Jack Stone <antennex@hotmail.com> Cc: freebsd-questions@freebsd.org Subject: Re: kern.hz="100" stops high-pitched whine Message-ID: <46892D0B.3030205@mac.com> In-Reply-To: <BAY125-F3001869A4CBB8CAF4B378BCC0D0@phx.gbl> References: <BAY125-F3001869A4CBB8CAF4B378BCC0D0@phx.gbl>
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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. -- -Chuck
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