From owner-freebsd-xen@FreeBSD.ORG Fri Jan 30 15:31:48 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 6B42D106571D for ; Fri, 30 Jan 2009 15:31:48 +0000 (UTC) (envelope-from gofx-freebsd-xen@m.gmane.org) Received: from ciao.gmane.org (main.gmane.org [80.91.229.2]) by mx1.freebsd.org (Postfix) with ESMTP id 212C08FC21 for ; Fri, 30 Jan 2009 15:31:47 +0000 (UTC) (envelope-from gofx-freebsd-xen@m.gmane.org) Received: from list by ciao.gmane.org with local (Exim 4.43) id 1LSvLK-0000mk-CK for freebsd-xen@freebsd.org; Fri, 30 Jan 2009 15:31:42 +0000 Received: from 92.116.198.155 ([92.116.198.155]) by main.gmane.org with esmtp (Gmexim 0.1 (Debian)) id 1AlnuQ-0007hv-00 for ; Fri, 30 Jan 2009 15:31:42 +0000 Received: from js by 92.116.198.155 with local (Gmexim 0.1 (Debian)) id 1AlnuQ-0007hv-00 for ; Fri, 30 Jan 2009 15:31:42 +0000 X-Injected-Via-Gmane: http://gmane.org/ To: freebsd-xen@freebsd.org From: Julian Stecklina Date: Fri, 30 Jan 2009 16:31:29 +0100 Lines: 37 Message-ID: <8763jwkdym.fsf@tabernacle.localnet> References: <87ocxp1tym.fsf@tabernacle.localnet> <1233285247.24925.4.camel@phoenix.blechhirn.net> <871vul1nqk.fsf@tabernacle.localnet> <9bbcef730901300214s19c91071vf9241cd7cd40ba57@mail.gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-Complaints-To: usenet@ger.gmane.org X-Gmane-NNTP-Posting-Host: 92.116.198.155 X-Archive: encrypt User-Agent: Gnus/5.1008 (Gnus v5.10.8) Cancel-Lock: sha1:LvRCYBnYu/t3Rtv64g97c80mBQI= Sender: news 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 15:31:51 -0000 Ivan Voras writes: > 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. Probably. > 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. I am going to do that once the timing stuff is figured out. No point in making benchmarks when the clock is confused. :) I cannot repeat it enough: Still great to see FreeBSD on Xen! Regards, -- Julian Stecklina Well, take it from an old hand: the only reason it would be easier to program in C is that you can't easily express complex problems in C, so you don't. - Erik Naggum (in comp.lang.lisp)