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=-0.7 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED 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 0C1D5C43331 for ; Tue, 12 Nov 2019 01:34:47 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id CF65320659 for ; Tue, 12 Nov 2019 01:34:46 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="nLHGcfjl" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727145AbfKLBep (ORCPT ); Mon, 11 Nov 2019 20:34:45 -0500 Received: from mail-oi1-f193.google.com ([209.85.167.193]:34893 "EHLO mail-oi1-f193.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726928AbfKLBep (ORCPT ); Mon, 11 Nov 2019 20:34:45 -0500 Received: by mail-oi1-f193.google.com with SMTP id n16so13352613oig.2; Mon, 11 Nov 2019 17:34:43 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=Mez+pVB2aSRl3joTyHwJYr7P2LRTYTKys9tINZyr2/o=; b=nLHGcfjlNdBxuy9OP6XPSYsFhgZMGPmqolg/5EycwX81Ugcx11fDqho6CztizdBIqS MMezND70FGWWDPdNUCRC6L6GZR7lXjBBsQF2KCAVzOErToHOUK/dvFYk625crMVRRei9 o9+SSSZJG2IKWoECw9Z7nP/e3ObaU06fq0hCq+Lws+uJJ4qaVDbtAdsKKp1dozrJY8k1 7MszZZwapqMNlbPPKJ/56Axu3MaYHHIffKMpjTN8fgycuzCk/TuEpWiUHlm7OwljNLra GhNBtIU/aDlPVq9NLm2NCAg8ssiuQLOKX1opP58suaU37+yrRKwyl5IIzboSVt0J+pZP HT+w== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=Mez+pVB2aSRl3joTyHwJYr7P2LRTYTKys9tINZyr2/o=; b=Kv3Lgl+txiRkiolHhZ362RME+AGLHRjxiuoh8TBpvFqLY6nG9DgvtZA89NhqYQt7q8 65V3bsB4U0pLeGdEur6AJ9D/x8LTMQybeWtqoGjcR9XSNssZAVL8fTJEwxOaPlLkLvLa ktdwbOoIq+VAPtkWlgebCMVnHL4Zn+BasSjUFB9SuFqUEwrJWvxryaygB4YDdXYZZ1wI /7y92kqE/Z60g/8cZwjeYS63+Gm8eOW8qgnLCaqtUhol0zxUhpL2gsJIN6ROjxHU1yg7 og1vPbt2YCmykP9c2bq6S1qIh3m/ACHLXuTJ/MaIVbRjw1tMzxEd9fJ1/g7pUDZ29Sx5 G+7w== X-Gm-Message-State: APjAAAXJWGM/dtb5xU5JR5vm2j2TBo4LIiGg/sDeinIXd9GVs8T0oTuz cC4Iv81pYuZf8G0eGiHCR1cSzG4YRObN3Mf0bKBWzg== X-Google-Smtp-Source: APXvYqwJ3B/cGGQ6QoFrMaYL6Rg2bBM5c8aoJ9Ym8QZ5I3Y/0F6FYh3ltg2Nnu9FWl0BwsBMtMJamH/b5tRnnsQZi6U= X-Received: by 2002:aca:5015:: with SMTP id e21mr1803688oib.174.1573522483255; Mon, 11 Nov 2019 17:34:43 -0800 (PST) MIME-Version: 1.0 References: <1573283135-5502-1-git-send-email-wanpengli@tencent.com> <1573283135-5502-2-git-send-email-wanpengli@tencent.com> <7a526814-c44e-c188-fba4-c6fb97b88b71@redhat.com> In-Reply-To: <7a526814-c44e-c188-fba4-c6fb97b88b71@redhat.com> From: Wanpeng Li Date: Tue, 12 Nov 2019 09:34:34 +0800 Message-ID: Subject: Re: [PATCH 2/2] KVM: LAPIC: micro-optimize fixed mode ipi delivery To: Paolo Bonzini Cc: LKML , kvm , =?UTF-8?B?UmFkaW0gS3LEjW3DocWZ?= , Sean Christopherson , Vitaly Kuznetsov , Wanpeng Li , Jim Mattson , Joerg Roedel Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 12 Nov 2019 at 05:59, Paolo Bonzini wrote: > > On 09/11/19 08:05, Wanpeng Li wrote: > > From: Wanpeng Li > > > > After disabling mwait/halt/pause vmexits, RESCHEDULE_VECTOR and > > CALL_FUNCTION_SINGLE_VECTOR etc IPI is one of the main remaining > > cause of vmexits observed in product environment which can't be > > optimized by PV IPIs. This patch is the follow-up on commit > > 0e6d242eccdb (KVM: LAPIC: Micro optimize IPI latency), to optimize > > redundancy logic before fixed mode ipi is delivered in the fast > > path. > > > > - broadcast handling needs to go slow path, so the delivery mode repair > > can be delayed to before slow path. > > I agree with this part, but is the cost of the irq->shorthand check > really measurable? I can drop the second part for v2. Wanpeng