From owner-freebsd-xen@FreeBSD.ORG Tue Feb 11 18:37:05 2014 Return-Path: Delivered-To: freebsd-xen@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [8.8.178.115]) (using TLSv1 with cipher ADH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTPS id F2F8222E for ; Tue, 11 Feb 2014 18:37:05 +0000 (UTC) Received: from o3.shared.sendgrid.net (o3.shared.sendgrid.net [208.117.48.85]) by mx1.freebsd.org (Postfix) with SMTP id 82C55121C for ; Tue, 11 Feb 2014 18:37:05 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha1; c=relaxed; d=sendgrid.info; h=from:mime-version:to:cc:subject:references:in-reply-to:content-type:content-transfer-encoding; s=smtpapi; bh=P9cV5F/bZ6CVXQfc0zfNoZoKnU4=; b=Cszyizk+ka83NJWENO WWYnx1CgdoTgh/0lVQCLb4GZ98OWVAW5usrUz7MBA60T3Xdrw+HK3anM4GNF9ywZ SPyRYE97dWhdMv150z7P7A3lZvvPFovKzczUJvc4uMIAG9cjAYq5h2XM2Kwwec8X cg4m81AqBIrLGOpUmxKmOkgxc= Received: by mf266.sendgrid.net with SMTP id mf266.25600.52FA6DD0C Tue, 11 Feb 2014 18:37:04 +0000 (UTC) Received: from mail.tarsnap.com (unknown [10.100.60.108]) by ismtpd-023 (SG) with ESMTP id 144223cf775.530d.214708 for ; Tue, 11 Feb 2014 18:37:04 +0000 (GMT) Received: (qmail 360 invoked from network); 11 Feb 2014 18:37:03 -0000 Received: from unknown (HELO clamshell.daemonology.net) (127.0.0.1) by ec2-107-20-205-189.compute-1.amazonaws.com with ESMTP; 11 Feb 2014 18:37:03 -0000 Received: (qmail 16625 invoked from network); 11 Feb 2014 18:36:24 -0000 Received: from unknown (HELO clamshell.daemonology.net) (127.0.0.1) by clamshell.daemonology.net with SMTP; 11 Feb 2014 18:36:24 -0000 Message-ID: <52FA6DA8.7030107@freebsd.org> Date: Tue, 11 Feb 2014 10:36:24 -0800 From: Colin Percival User-Agent: Mozilla/5.0 (X11; FreeBSD amd64; rv:24.0) Gecko/20100101 Thunderbird/24.0 MIME-Version: 1.0 To: "Justin T. Gibbs" , Karl Pielorz Subject: Re: FreeBSD 10.0-R as Xen 'guest' - clarification? References: <18819F918745D984B618D518@Mail-PC.tdx.co.uk> <7EC86263-B19E-4829-A601-F78DEDCEF7E9@scsiguy.com> In-Reply-To: <7EC86263-B19E-4829-A601-F78DEDCEF7E9@scsiguy.com> X-Enigmail-Version: 1.5.2 Content-Type: text/plain; charset=windows-1252 content-transfer-encoding: quoted-printable X-SG-EID: RUbAm5H8PjswBj/QH+sYVehaJogg3iBnZcyVi1bw/Iz+1kfzfmCWd2ev6DFF9NSAeuKrojRPeyagtJclHE8PHOoUTOCuXLwHXvzZTqA/V36oQjJXv9gw9563bxwhgX+oRTrFTk5BAO1X4fgLXKj79pRoutIBKutg2t+1WXjkUQg= Cc: freebsd-xen@FreeBSD.org X-BeenThere: freebsd-xen@freebsd.org X-Mailman-Version: 2.1.17 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: Tue, 11 Feb 2014 18:37:06 -0000 On 02/11/14 09:26, Justin T. Gibbs wrote:=0D > On Jan 29, 2014, at 8:28 AM, Karl Pielorz wrote:= =0D >> The man page for xen (man 4 xen) states you should have:=0D >>=0D >> options NO_ADAPTIVE_MUTEXES=0D >> options NO_ADAPTIVE_RWLOCKS=0D >> options NO_ADAPTIVE_SX=0D > =0D > The =93NO_ADAPTIVE=94 settings are an optimization when running in enviro= nments where different guests run on the same physical CPU. However, many = cloud providers seem to statically pin CPUs to VMs, which means the adaptiv= e lock optimization works as expected.=0D =0D ... and with static pinning, adding the NO_ADAPTIVE_FOO options causes a=0D significant drop in performance, so you really don't want them unless you'r= e=0D going to be sharing CPUs.=0D =0D -- =0D Colin Percival=0D Security Officer Emeritus, FreeBSD | The power to serve=0D Founder, Tarsnap | www.tarsnap.com | Online backups for the truly paranoid