From owner-freebsd-xen@FreeBSD.ORG Fri Jan 30 10:35:41 2009 Return-Path: Delivered-To: freebsd-xen@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id A0665106566B for ; Fri, 30 Jan 2009 10:35:41 +0000 (UTC) (envelope-from ivoras@gmail.com) Received: from mail-fx0-f15.google.com (mail-fx0-f15.google.com [209.85.220.15]) by mx1.freebsd.org (Postfix) with ESMTP id 2D41A8FC20 for ; Fri, 30 Jan 2009 10:35:40 +0000 (UTC) (envelope-from ivoras@gmail.com) Received: by fxm8 with SMTP id 8so150450fxm.19 for ; Fri, 30 Jan 2009 02:35:40 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:mime-version:sender:received:in-reply-to :references:date:x-google-sender-auth:message-id:subject:from:to:cc :content-type:content-transfer-encoding; bh=Iqh9VUC9AVuijxT9Gp0DksqoFuHTavCiG0TA9HXhUaM=; b=egg90ZZqrOuOtotWJn+Rqm5ZlqjGfRLO4OYKMuj9sZvgvoSKs5SAyaLEhhOe6a+Ppz 3xkjjyaY0HdP36J0W5T3CRJqhczZzIa28OOtS/JD+SW0tH9PjTmlNxNaFYLsG5kVaVhm jjUPULQbbK8BAfxQpXYo6bQw+5yMIk7v+4Hcs= DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:sender:in-reply-to:references:date :x-google-sender-auth:message-id:subject:from:to:cc:content-type :content-transfer-encoding; b=ASugzEYYCGLYCjk/H39hE0NLU91O6R++cYKOtHgAtksgoDjAVc2HTCKX6Kd2n+oC+N /Sve9eGCfQO7WyOrOHx92Dq1+stC4fZukBMxhDGphdAaCYfb/zspNX+JYqWRdF/aAZTm qrquayesP02MdAAWHMp1jhGP4D19sOmNShHGI= MIME-Version: 1.0 Sender: ivoras@gmail.com Received: by 10.181.208.11 with SMTP id k11mr17584bkq.180.1233310459315; Fri, 30 Jan 2009 02:14:19 -0800 (PST) In-Reply-To: <871vul1nqk.fsf@tabernacle.localnet> References: <87ocxp1tym.fsf@tabernacle.localnet> <1233285247.24925.4.camel@phoenix.blechhirn.net> <871vul1nqk.fsf@tabernacle.localnet> Date: Fri, 30 Jan 2009 11:14:19 +0100 X-Google-Sender-Auth: c1a95576ef81bcb0 Message-ID: <9bbcef730901300214s19c91071vf9241cd7cd40ba57@mail.gmail.com> From: Ivan Voras To: Julian Stecklina Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Cc: freebsd-xen@freebsd.org Subject: Re: kern.hz = 10 X-BeenThere: freebsd-xen@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Discussion of the freebsd port to xen - implementation and usage List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 30 Jan 2009 10:35:42 -0000 2009/1/30 Julian Stecklina : > Mister Olli writes: > >> Hi, >> >> I've never experimented with the kern.hz variable, but on all >> configuration examples for 8-CURRENT if always seen 'kern.hz=100'. >> >>>From where did you get your configuration? > > I use the default config (albeit renamed to BLITZXEN) from 8-CURRENT. Due to bad performance of high HZ in VMs, in 8-CURRENT it is explicitly reduced to 10 if the kernel is running under any kind of virtual environment. This is a somewhat theoretical number and probably needs tuning. If you're interested in trying it out, you can increase it by adding "kern.hz=xxx" to /boot/loader.conf and seeing what is the actual performance influence of high HZ under Xen.