From owner-freebsd-xen@FreeBSD.ORG Thu Oct 29 23:33:25 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 BDB0A106566B for ; Thu, 29 Oct 2009 23:33:25 +0000 (UTC) (envelope-from sysconfig@ossafe.org) Received: from mx2.the-ally.co.uk (mx2.the-ally.co.uk [95.154.227.236]) by mx1.freebsd.org (Postfix) with ESMTP id 784568FC1D for ; Thu, 29 Oct 2009 23:33:25 +0000 (UTC) Received: from mx2.the-ally.co.uk (localhost.localdomain [127.0.0.1]) by mx2.the-ally.co.uk (Postfix) with ESMTP id F1819ED0997; Thu, 29 Oct 2009 23:33:23 +0000 (GMT) DKIM-Signature: v=1; a=rsa-sha1; c=relaxed; d=ossafe.org; h=subject :mime-version:content-type:from:in-reply-to:date:cc :content-transfer-encoding:message-id:references:to; s= selector1; bh=WCFRWOCkyrAy01F1YqnQfKNPa3Y=; b=RMwgQqdcZ+1svUVVXn HDbJ6PELMHxsVS/4FKvY2vGwJ5iK+GnAZhuaZ78H+CEWQCMwZqynRmv8vzQGwhbV 5gBiLvaw2o61ZvFD8FiaGNvN92YfqsXv1cJBJyeZwyAIbLh+oHOLbvFRDxVyCNYt oy1ifaoBzeDKCBxMeyrUIy2T0= DomainKey-Signature: a=rsa-sha1; c=nofws; d=ossafe.org; h=subject :mime-version:content-type:from:in-reply-to:date:cc :content-transfer-encoding:message-id:references:to; q=dns; s= selector1; b=ZEQdmHGZcLefLLVjtWadPAE8zpjPW1uYqY0Qh9XwanG/CbNj4/b Sm3gE6n1HfDGkE9HnCTo5ZOJouOaUhSd8d9Qqkp3XOkgO36ON6LVRPiAJ4q7MHkX ZR7m3vNMNeFPdxXhZJJq+eMuMKmxycNIMGwffbfZu7RY4tTxJfLsy80c= Received: from [10.2.2.20] (unknown [10.2.2.20]) by mx2.the-ally.co.uk (Postfix) with ESMTP id B2FAFED0994; Thu, 29 Oct 2009 23:33:23 +0000 (GMT) Mime-Version: 1.0 (Apple Message framework v1076) Content-Type: text/plain; charset=us-ascii; format=flowed; delsp=yes From: Carsten Heesch In-Reply-To: <869459F8-7490-4270-84D0-A1168002E509@ossafe.org> Date: Thu, 29 Oct 2009 23:33:23 +0000 Content-Transfer-Encoding: 7bit Message-Id: References: <869459F8-7490-4270-84D0-A1168002E509@ossafe.org> To: Carsten Heesch X-Mailer: Apple Mail (2.1076) Cc: freebsd-xen@freebsd.org Subject: Re: SCHED_ULE vs SCHED_4BSD for XENHVM domU 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: Thu, 29 Oct 2009 23:33:25 -0000 Oops, sorry for posting this twice. I thought it didn't go through with the first attempt. On 29 Oct 2009, at 23:27, Carsten Heesch wrote: > Hi guys, > > After FreeBSD 8.0-RC2 is working well (for me) on Xen 3.3.1, I > somehow made an interesting observation: > > Even if the FreeBSD domU does absolutely nothing, each of the > assigned vCPUs will be reported by xentop as using 15%-25% CPU time. > It doesn't matter, if domU is running with 1 or 4 vCPUs. All of them > float at the same level. > > On the same Xen box five other domU's (CentOS 5.2-5.4) have an idle > CPU percentage of 0 to 0.5%. > > So I played a bit and figured out that changing the scheduler in the > XENHVM kernel configuration from "option SCHED_ULE" to "option > SCHED_4BSD" resolves this problem. The idle state of the FreeBSD > domU is now identical to the CentOS domU's. > > However, this of course means using an old (maybe even deprecated?) > scheduler, which moreover isn't the best choice for multiple > (virtual) CPUs. > > The configuration I tested on is: > Intel i7 920 Quad-Core with Hyperthreading (8 logical CPUs) > Citrix XenServer 5.5 (based on CentOS 5.2, Xen 3.3.1) > > > Any thoughts, ideas, solutions? > > > Thanks! > > Carsten > > > _______________________________________________ > freebsd-xen@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-xen > To unsubscribe, send any mail to "freebsd-xen-unsubscribe@freebsd.org" Best regards, Carsten Heesch Mobile: +44 (0)7889-129998 Mail: carsten@heesch.me.uk Skype: carstenh74