On 7/2/07, Jack Stone <[EMAIL PROTECTED]> wrote:
>From: Chuck Swiger <[EMAIL PROTECTED]>
>To: cpghost <[EMAIL PROTECTED]>
>CC: questions <freebsd-questions@freebsd.org>
>Subject: Re: kern.hz="100" stops high-pitched whine
>Date: Sun, 01 Jul 2007 09:46:19 -0400
>
>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.
>
>--
>-Chuck
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?
Thanks,
Jack
I don't know if the info is correct up to now or not, but I use pf
firewall, and I run IRC servers, I saw it in NOTES.
#####################################################################
# NETWORKING OPTIONS
#
# DEVICE_POLLING adds support for mixed interrupt-polling handling
# of network device drivers, which has significant benefits in terms
# of robustness to overloads and responsivity, as well as permitting
# accurate scheduling of the CPU time between kernel network processing
# and other activities. The drawback is a moderate (up to 1/HZ seconds)
# potential increase in response times.
# It is strongly recommended to use HZ=1000 or 2000 with DEVICE_POLLING
# to achieve smoother behaviour.
# Additionally, you can enable/disable polling at runtime with help of
# the ifconfig(8) utility, and select the CPU fraction reserved to
# userland with the sysctl variable kern.polling.user_frac
# (default 50, range 0..100).
#
# Not all device drivers support this mode of operation at the time of
# this writing. See polling(4) for more details.
options DEVICE_POLLING
--
Maybe it's out of date now for 2000?
--
Regards,
-Abdullah Ibn Hamad Al-Marri
Arab Portal
http://www.WeArab.Net/
_______________________________________________
freebsd-questions@freebsd.org mailing list
http://lists.freebsd.org/mailman/listinfo/freebsd-questions
To unsubscribe, send any mail to "[EMAIL PROTECTED]"
