From owner-freebsd-questions@FreeBSD.ORG Mon Jul 2 17:52:26 2007 Return-Path: X-Original-To: freebsd-questions@freebsd.org Delivered-To: freebsd-questions@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [69.147.83.52]) by hub.freebsd.org (Postfix) with ESMTP id 063A516A400 for ; Mon, 2 Jul 2007 17:52:26 +0000 (UTC) (envelope-from almarrie@gmail.com) Received: from an-out-0708.google.com (an-out-0708.google.com [209.85.132.240]) by mx1.freebsd.org (Postfix) with ESMTP id B4A9213C48A for ; Mon, 2 Jul 2007 17:52:25 +0000 (UTC) (envelope-from almarrie@gmail.com) Received: by an-out-0708.google.com with SMTP id c14so382084anc for ; Mon, 02 Jul 2007 10:52:24 -0700 (PDT) DKIM-Signature: a=rsa-sha1; c=relaxed/relaxed; d=gmail.com; s=beta; h=domainkey-signature:received:received:message-id:date:from:to:subject:cc:in-reply-to:mime-version:content-type:content-transfer-encoding:content-disposition:references; b=nBz/UKMuGMTH4vfj1hOr8/57ucTrEca29bIGB9+3kqngj/KTNCg1lwsUchpV9/cqY2aCb+C7+1sjqq6g6WqzsBPHLtq2jPDxKkSLnONYpAHf4rsgcW5dG0yeHI8oawGnU8C9DR/TOfhJz8nwC6N+i9jRLA/RDXNMm1MXNmhXo54= DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=beta; h=received:message-id:date:from:to:subject:cc:in-reply-to:mime-version:content-type:content-transfer-encoding:content-disposition:references; b=QhfEJEW+6pls0JOoNxE64uQvu+4gOtsO6neOqo/y9fpM9sZ0TOQtQCbfJ7Ny5SbFVIz7vSGJCBUaHp1V5+p24T/rFpWHyn04i7SUudITmbDdir71NwPw/8f7CO8x3vIqcXX6ZrOerbTSQPV3/Z2Jb37sgpNUSjVX6JrMC5PJ4IE= Received: by 10.100.108.11 with SMTP id g11mr3815467anc.1183398744536; Mon, 02 Jul 2007 10:52:24 -0700 (PDT) Received: by 10.100.9.14 with HTTP; Mon, 2 Jul 2007 10:52:24 -0700 (PDT) Message-ID: <499c70c0707021052p34e5197cjdfd8b956811b7fd6@mail.gmail.com> Date: Mon, 2 Jul 2007 20:52:24 +0300 From: "Abdullah Ibn Hamad Al-Marri" To: "Jack Stone" In-Reply-To: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Content-Disposition: inline References: <4687B02B.7080106@mac.com> Cc: freebsd-questions@freebsd.org Subject: Re: kern.hz="100" stops high-pitched whine X-BeenThere: freebsd-questions@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: User questions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 02 Jul 2007 17:52:26 -0000 On 7/2/07, Jack Stone wrote: > >From: Chuck Swiger > >To: cpghost > >CC: questions > >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/