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

cpghost cpghost at
Mon Jul 2 12:04:57 UTC 2007

Chuck Swiger wrote:
> cpghost wrote:
>> Are there any reasons NOT changing kern.hz from the
>> default 1000 back to 100? With my typical mix of
>> desktop apps (EPIA) and networking / server (Soekris),
>> everything seems to be running just as smoothly with
>> 100 Hz than with 1000 Hz (testing now for two weeks
>> without problems). Even playing videos with mplayer
>> on the EPIA doesn't look different in any way.
>> Is it okay to stay with 100 Hz with this type of
>> low-speed CPU/boards? Or are there some compelling
>> reasons not to?
> Actually, many Unix systems ran with HZ=100 until a few years ago, 
> about when Gb ethernet and CPUs became common.  A slower machine like 
> the EPIA boxes do quite well with HZ=100/200/250 or so...HZ=1000 is 
> better if you have a fast box running lots of concurrent processes, 
> and/or are proxying or routing network traffic where the difference 
> between 10 ms and 1ms of latency adds up and/or effects other systems.

Ah, thank you! It definitely works very well here with HZ=100. :)


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