From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Vrabel Subject: Re: [PATCH RFC v2 0/4] HVM x86 deprivileged mode operations Date: Thu, 3 Sep 2015 17:15:50 +0100 Message-ID: <55E87236.4020705@citrix.com> References: <1441296086-18209-1-git-send-email-Ben.Catterall@citrix.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Received: from mail6.bemta14.messagelabs.com ([193.109.254.103]) by lists.xen.org with esmtp (Exim 4.72) (envelope-from ) id 1ZXXBT-0000bu-VR for xen-devel@lists.xenproject.org; Thu, 03 Sep 2015 16:16:20 +0000 In-Reply-To: <1441296086-18209-1-git-send-email-Ben.Catterall@citrix.com> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: Ben Catterall , xen-devel@lists.xenproject.org Cc: keir@xen.org, jbeulich@suse.com, george.dunlap@eu.citrix.com, andrew.cooper3@citrix.com, tim@xen.org, Aravind.Gopalakrishnan@amd.com, suravee.suthikulpanit@amd.com, boris.ostrovsky@oracle.com, ian.campbell@citrix.com List-Id: xen-devel@lists.xenproject.org On 03/09/15 17:01, Ben Catterall wrote: > > Intel Intel 2.2GHz Xeon E5-2407 0 processor: > -------------------------------------------- > 1.55e-06 seconds was the average time for performing the write without the > deprivileged code running. > > 5.75e-06 seconds was the average time for performing the write with the > deprivileged code running. > > So approximately 351% overhead > > AMD Opteron 2376: > ----------------- > 1.74e-06 seconds was the average time for performing the write without the > deprivileged code running. > 3.10e-06 seconds was the average time for performing the write with an entry and > exit from deprvileged mode. > > So approximately 178% overhead. How does this compare to the overhead of passing the I/O through to qemu? David