From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE, SPF_PASS,USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 717D6C433E0 for ; Fri, 15 Jan 2021 08:52:21 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 3936323329 for ; Fri, 15 Jan 2021 08:52:21 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730201AbhAOIv6 (ORCPT ); Fri, 15 Jan 2021 03:51:58 -0500 Received: from mga05.intel.com ([192.55.52.43]:25574 "EHLO mga05.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726817AbhAOIv4 (ORCPT ); Fri, 15 Jan 2021 03:51:56 -0500 IronPort-SDR: c8+qbs1J7C5cUU6b+f2lmzXQl9ZIrYV8yIb6Ha+92DE6lxuvt45SP/MWG3i2wSiYKh5pOjPv07 QnYJcYodB2LQ== X-IronPort-AV: E=McAfee;i="6000,8403,9864"; a="263313699" X-IronPort-AV: E=Sophos;i="5.79,349,1602572400"; d="scan'208";a="263313699" Received: from orsmga008.jf.intel.com ([10.7.209.65]) by fmsmga105.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 15 Jan 2021 00:51:13 -0800 IronPort-SDR: 2DWi2BuGZEuH8CvySrdMz0szSkdssIE/dCzkPYdMnYOeTdh2TLG3jRQ/JqTQrNBuGYwxPcJG7o bDFMkQxWbh0g== X-IronPort-AV: E=Sophos;i="5.79,349,1602572400"; d="scan'208";a="382591418" Received: from likexu-mobl1.ccr.corp.intel.com (HELO [10.238.4.93]) ([10.238.4.93]) by orsmga008-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 15 Jan 2021 00:51:03 -0800 Subject: Re: [RESEND v13 00/10] KVM: x86/pmu: Guest Last Branch Recording Enabling To: Alex Shi , Paolo Bonzini , Sean Christopherson Cc: Ingo Molnar , Thomas Gleixner , Borislav Petkov , "H . Peter Anvin" , ak@linux.intel.com, wei.w.wang@intel.com, kan.liang@intel.com, x86@kernel.org, kvm@vger.kernel.org, linux-kernel@vger.kernel.org, Joerg Roedel , Jim Mattson , Vitaly Kuznetsov , Wanpeng Li , Like Xu References: <20210108013704.134985-1-like.xu@linux.intel.com> <3deac361-05fa-60a5-0d88-4f6b968f10bf@linux.alibaba.com> From: "Xu, Like" Message-ID: <307385ae-cd3e-8d06-ffa9-dcd297ec9a8a@intel.com> Date: Fri, 15 Jan 2021 16:51:01 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:78.0) Gecko/20100101 Thunderbird/78.6.1 MIME-Version: 1.0 In-Reply-To: <3deac361-05fa-60a5-0d88-4f6b968f10bf@linux.alibaba.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Content-Language: en-US Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org Hi Alex, Thank you for trying this guest feature on multiple Intel platforms! If you have more specific comments or any concerns, just let me know. --- thx, likexu On 2021/1/15 16:19, Alex Shi wrote: > > 在 2021/1/8 上午9:36, Like Xu 写道: >> Because saving/restoring tens of LBR MSRs (e.g. 32 LBR stack entries) in >> VMX transition brings too excessive overhead to frequent vmx transition >> itself, the guest LBR event would help save/restore the LBR stack msrs >> during the context switching with the help of native LBR event callstack >> mechanism, including LBR_SELECT msr. >> > Sounds the feature is much helpful for VMM guest performance tunning. > Good job! > > Thanks > Alex