From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Yang, Sheng" Subject: Re: Host latency peaks due to kvm-intel Date: Mon, 27 Jul 2009 09:11:59 +0800 Message-ID: <200907270912.00470.sheng.yang@intel.com> References: <4A68A6E5.6010808@siemens.com> <4A6AD69E.7030201@web.de> <4A6CAB8B.4080706@intel.com> Mime-Version: 1.0 Content-Type: Text/Plain; charset="utf-8" Content-Transfer-Encoding: 7bit Cc: Jan Kiszka , Avi Kivity , Gregory Haskins , "kvm-devel" , RT To: "H. Peter Anvin" Return-path: Received: from mga11.intel.com ([192.55.52.93]:36929 "EHLO mga11.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754647AbZG0BMi (ORCPT ); Sun, 26 Jul 2009 21:12:38 -0400 In-Reply-To: <4A6CAB8B.4080706@intel.com> Content-Disposition: inline Sender: linux-rt-users-owner@vger.kernel.org List-ID: On Monday 27 July 2009 03:16:27 H. Peter Anvin wrote: > Jan Kiszka wrote: > > Avi Kivity wrote: > >> On 07/24/2009 12:41 PM, Jan Kiszka wrote: > >>> I vaguely recall that someone promised to add a feature reporting > >>> facility for all those nice things, modern VM-extensions may or may not > >>> support (something like or even an extension of /proc/cpuinfo). What is > >>> the state of this plan? Would be specifically interesting for Intel > >>> CPUs as there seem to be many of them out there with restrictions for > >>> special use cases - like real-time. > >> > >> Newer kernels do report some vmx features (like flexpriority) in > >> /proc/cpuinfo but not all. > > > > Ah, nice. Then we just need this? > > Fine with me. > > Acked-by: H. Peter Anvin > > However, I guess the real question if we shouldn't export ALL VMX > features in a consistent way instead? > When I add feature reporting to cpuinfo, I just put highlight features there, otherwise the VMX feature list would at least as long as CPU one. I have also suggested another field for virtualization feature for it, but some concern again userspace tools raised. For we got indeed quite a lot features, and would get more, would it better to export the part of struct vmcs_config entries(that's pin_based_exec_ctrl, cpu_based_exec_ctrl, and cpu_based_2nd_exec_ctrl) through sys/module/kvm_intel/? Put every feature to cpuinfo seems not that necessary for such a big list. -- regards Yang, Sheng