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=-7.9 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,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 5E308C48BE8 for ; Mon, 14 Jun 2021 09:55:06 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 36DE261245 for ; Mon, 14 Jun 2021 09:55:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232718AbhFNJ5I (ORCPT ); Mon, 14 Jun 2021 05:57:08 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]:21228 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232630AbhFNJ5H (ORCPT ); Mon, 14 Jun 2021 05:57:07 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1623664504; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=5GpSfzrx0xJrJtYkyiWQUMGDvrq/2BMaXO5677R7IKE=; b=RYCcivvO4BsWm1hlYtv5UT9oPAFoNJHbSiIT/4mQiOeadFY/zbouTtu2f6hdFiSHkKlaoy EnlTiAJlmt+gFXb54rJ2wgQ4pwqZ/tSDyBapD+CWzmK4vcae8QBJJNv8eyoN8dJh3tyPDI wI0M2DFTsDNJQS1bLpa4ZIDX1Oe8Qcg= Received: from mail-ed1-f70.google.com (mail-ed1-f70.google.com [209.85.208.70]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-500-YFYzoSO8Nl6rDl_t26bo3w-1; Mon, 14 Jun 2021 05:55:03 -0400 X-MC-Unique: YFYzoSO8Nl6rDl_t26bo3w-1 Received: by mail-ed1-f70.google.com with SMTP id p24-20020aa7c8980000b0290393c37fdcb8so8795091eds.6 for ; Mon, 14 Jun 2021 02:55:02 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:cc:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=5GpSfzrx0xJrJtYkyiWQUMGDvrq/2BMaXO5677R7IKE=; b=OUUnimE1Zoq+sv+VzcwhcFcUtRICcT/gZICb5UY9o3oSQK3nUaehIcfZw4COD4wblU DAzAB0yfY19w3YC4raGsAMUU6GnUs7IGdXcEgNsdopnUlkFFlLmxq4zXTuFqkdgLFta1 MTNHj0CrFxBWnZ0CLn/qwRcJTAbsbee8Y6b7Z1HIIRDhaSrojAkAM6dt+MDppXGVXEju zAy+dGU9sJwgR7Jmkq+SY//TOZJelv2MYLAzh2vM+IYtVCvs/+s/GDW2L2psAmIRKjL2 ptP1YlFkftxCOjgtOfOi83QpuUEpboN0RrGuCa04lYAgvEFgJIOSMWASa1HurMzyu6nP rDYw== X-Gm-Message-State: AOAM532eXtagBhv29m8tqvMQixhXAwp7l5Bto72l8AAkTAYRFtQ8n/5z CKySVG0C+w9kBtZz9WwWmqJyQSrXlQ7PPesIhvQF4906A/QACGkjc3BStihX7km7ZxZiglqfC1X Utccwo2xfkMbG X-Received: by 2002:a17:906:c314:: with SMTP id s20mr14579796ejz.355.1623664501890; Mon, 14 Jun 2021 02:55:01 -0700 (PDT) X-Google-Smtp-Source: ABdhPJwWNeLkqs/C9K4xRGmFGyx+BAjVTd2ZevdqxiEUIYgVkivaKVYWkbSy2j655l8bktpDoPsDkA== X-Received: by 2002:a17:906:c314:: with SMTP id s20mr14579786ejz.355.1623664501756; Mon, 14 Jun 2021 02:55:01 -0700 (PDT) Received: from ?IPv6:2001:b07:6468:f312:c8dd:75d4:99ab:290a? ([2001:b07:6468:f312:c8dd:75d4:99ab:290a]) by smtp.gmail.com with ESMTPSA id gw7sm6876865ejb.5.2021.06.14.02.55.00 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 14 Jun 2021 02:55:01 -0700 (PDT) Subject: Re: [PATCH 0/8] KVM: x86/mmu: Fast page fault support for the TDP MMU To: David Matlack , kvm@vger.kernel.org Cc: Ben Gardon , Joerg Roedel , Jim Mattson , Wanpeng Li , Vitaly Kuznetsov , Sean Christopherson , Junaid Shahid , Andrew Jones References: <20210611235701.3941724-1-dmatlack@google.com> From: Paolo Bonzini Message-ID: <639c54a4-3d6b-8b28-8da7-e49f2f87e025@redhat.com> Date: Mon, 14 Jun 2021 11:54:59 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.10.1 MIME-Version: 1.0 In-Reply-To: <20210611235701.3941724-1-dmatlack@google.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org On 12/06/21 01:56, David Matlack wrote: > This patch series adds support for the TDP MMU in the fast_page_fault > path, which enables certain write-protection and access tracking faults > to be handled without taking the KVM MMU lock. This series brings the > performance of these faults up to par with the legacy MMU. Hi David, I have one very basic question: is the speedup due to lock contention, or to cacheline bouncing, or something else altogether? In other words, what do the profiles look like before vs. after these patches? Thanks, Paolo