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=-13.3 required=3.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_IN_DEF_DKIM_WL 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 36BC4C433B4 for ; Wed, 21 Apr 2021 16:19:45 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D862561168 for ; Wed, 21 Apr 2021 16:19:44 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S244205AbhDUQUR (ORCPT ); Wed, 21 Apr 2021 12:20:17 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54038 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237441AbhDUQUQ (ORCPT ); Wed, 21 Apr 2021 12:20:16 -0400 Received: from mail-pg1-x534.google.com (mail-pg1-x534.google.com [IPv6:2607:f8b0:4864:20::534]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 645BCC06174A for ; Wed, 21 Apr 2021 09:19:41 -0700 (PDT) Received: by mail-pg1-x534.google.com with SMTP id t22so30390270pgu.0 for ; Wed, 21 Apr 2021 09:19:41 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=mbowa4eGXVqgNRFl8Ptq/4t6AHbidKrVDS7uCXbthl0=; b=jrcHDTFu9cpMi0xHYHXjqVifJleR2lPm5sllZXnWakKs6LOxMF36iBVwx8NJifaig0 1iQGU6B6C2AtTU85aOq6UML+RmQ6zerTwARKx8rHUjWkfM1v9zoKhTvvgOOMhCGalLUx q+nWK84K3zKyXoGcZWcMXOPcY/g6kNj5l+HYJJLL1qsMJBt5PiLPVJXfAGYkowOHYiRd y/IowPQH6Zczzrci5sCDhsXJuhZ0yv0mZW7/LlkMUJbZYzARlBeR/MdmlPofuMS0jN4D 6SU8VppMFKhLbqXf9fhekF/9K/9rhAftQFQFvdk7uGPKO8nyuOacM8EJgwEcjfP2giDl ohsg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=mbowa4eGXVqgNRFl8Ptq/4t6AHbidKrVDS7uCXbthl0=; b=RqD/LAE57flMlNTkjkpgcKopOc9CYomQUwkMXihj6mHX2bOiLuGXqdHany/uZ2vOSz /nVb7HGUzhpd0nNClih8zxQdHnqK+HeHw2qxNsOVjQ8PUlyYZT3haH0/nn2Sh6D2E7j8 l0LE0OhutujDMHMliMKnFSb7RIn23HUj/7KgQA6lttZrYQRPqPX0Rl9emJdI5zEQJp6J Rndo3XBWjUGE8HLea+v9z4mPMucHwnNPCmrHjNH+B/DSeFw+KCljlVTW/FpAsSP1UJP4 YNXMd2hY6H3q/N0L75gxsnlac1i/iFYC/8gzB8tgcp+ju2YaVwK9HNbzQb4pMJ5Ft9WP J4QA== X-Gm-Message-State: AOAM530eycn4KeNFnHz3IkIaBXSO74D0EbJJcX2mBZ7x924wdF0WoZMo lwjiZJCNRG4dVnrx0sii3dQStA== X-Google-Smtp-Source: ABdhPJyFws8ZWFDMZIipUdDjla37bGQRxTnJtkCwK4lkHEftHRqpoty09GrTTnBh2rsn7NW7nQp5PQ== X-Received: by 2002:aa7:9e4f:0:b029:25e:cf65:c554 with SMTP id z15-20020aa79e4f0000b029025ecf65c554mr16686787pfq.66.1619021980804; Wed, 21 Apr 2021 09:19:40 -0700 (PDT) Received: from google.com (240.111.247.35.bc.googleusercontent.com. [35.247.111.240]) by smtp.gmail.com with ESMTPSA id a7sm2845087pjm.0.2021.04.21.09.19.40 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 21 Apr 2021 09:19:40 -0700 (PDT) Date: Wed, 21 Apr 2021 16:19:36 +0000 From: Sean Christopherson To: Kenta Ishiguro Cc: Paolo Bonzini , Vitaly Kuznetsov , Wanpeng Li , Jim Mattson , Joerg Roedel , David Hildenbrand , kvm@vger.kernel.org, linux-kernel@vger.kernel.org, pl@sslab.ics.keio.ac.jp, kono@sslab.ics.keio.ac.jp Subject: Re: [RFC PATCH 0/2] Mitigating Excessive Pause-Loop Exiting in VM-Agnostic KVM Message-ID: References: <20210421150831.60133-1-kentaishiguro@sslab.ics.keio.ac.jp> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210421150831.60133-1-kentaishiguro@sslab.ics.keio.ac.jp> Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org On Thu, Apr 22, 2021, Kenta Ishiguro wrote: > To solve problems (2) and (3), patch 2 monitors IPI communication between > vCPUs and leverages the relationship between vCPUs to select boost > candidates. The "[PATCH] KVM: Boost vCPU candidiate in user mode which is > delivering interrupt" patch > (https://lore.kernel.org/kvm/CANRm+Cy-78UnrkX8nh5WdHut2WW5NU=UL84FRJnUNjsAPK+Uww@mail.gmail.com/T/) > seems to be effective for (2) while it only uses the IPI receiver > information. On the IPI side of thing, I like the idea of explicitly tracking the IPIs, especially if we can simplify the implementation, e.g. by losing the receiver info and making ipi_received a bool. Maybe temporarily table Wanpeng's patch while this approach is analyzed?