From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Vrabel Subject: Re: [RFC PATCHv2 0/3]: x86/ept: reduce translation invalidation impact Date: Thu, 3 Dec 2015 15:59:05 +0000 Message-ID: <566066C9.8040208@citrix.com> References: <1447440595-1151-1-git-send-email-david.vrabel@citrix.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Received: from mail6.bemta4.messagelabs.com ([85.158.143.247]) by lists.xen.org with esmtp (Exim 4.72) (envelope-from ) id 1a4WHp-0007ZR-P7 for xen-devel@lists.xenproject.org; Thu, 03 Dec 2015 15:59:13 +0000 In-Reply-To: List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: "Tian, Kevin" , David Vrabel , "xen-devel@lists.xenproject.org" Cc: George Dunlap , Andrew Cooper , Tim Deegan , "Nakajima, Jun" , Jan Beulich List-Id: xen-devel@lists.xenproject.org On 02/12/15 07:14, Tian, Kevin wrote: >> From: David Vrabel [mailto:david.vrabel@citrix.com] >> Sent: Saturday, November 14, 2015 2:50 AM >> >> This RFC series improves the performance of EPT by reducing the impact >> of the translation invalidations (ept_sync_domain()). Two approaches >> are used: >> >> a) Removing unnecessary invalidations after fixing misconfigured >> entries (after a type change). >> >> b) Deferring invalidations until the p2m write lock is released. > > Do you have a sense which one above incurs more overhead? No, but fixing (a) probably gives us the biggest win since it removes the sync entirely. David