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 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 685C3C433EF for ; Wed, 27 Oct 2021 00:47:04 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4274460230 for ; Wed, 27 Oct 2021 00:47:04 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235809AbhJ0At1 (ORCPT ); Tue, 26 Oct 2021 20:49:27 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55318 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230373AbhJ0AtZ (ORCPT ); Tue, 26 Oct 2021 20:49:25 -0400 Received: from mail-oi1-x231.google.com (mail-oi1-x231.google.com [IPv6:2607:f8b0:4864:20::231]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 830BBC061570; Tue, 26 Oct 2021 17:47:01 -0700 (PDT) Received: by mail-oi1-x231.google.com with SMTP id q124so1154625oig.3; Tue, 26 Oct 2021 17:47:01 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=8xB69BiQvruCUDzQOHPnB7DSueM5V+wuTZ2lx3/6o88=; b=k/WFPBeaDle6GpaxhQryQ8xKi5z911CVHoxJ666LxkcFYM8YQrcuReTOBsvTEKbGV3 V4Dw6e3eSXiADD+e2k27qOzL6GYD5eaF9+nryW/PBeTtsp6g1ocnka9zR3YJfsm/i0HY 1FALmHZ3ohohuKAgbKfWpGWY1xTAOsIU75LYK8dUbAr+IIHtRi4eqt6iBaNPMQJvrDUV e9kuVA8vYLYjkPR2vEoLa3N6AZhwjF9Cmq6wv4V7TugtcPLXsKZFTkqg5DYW+9CRC+sX ixJ4nwWIWwDL0R0b5YbWEhqijCCG8PWoUWuDz8bs/BLk9eqP2/34ui4gx5NX/xjtGJYG +5qQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=8xB69BiQvruCUDzQOHPnB7DSueM5V+wuTZ2lx3/6o88=; b=PqpAvRgVV30OfbtULK0MF+K5rUy5ImOgMsoP01vzwRbjuUWHunYzBJcMzHwabsFeGG S1n81XakpTxwLWH6XaNKj+WKomsxt6TsbBroi7ZJsTiSbUOnMti+LQ8oFFiFoq6ZKAVQ /SAP7Xlldf3YXwJBHcdkrdaaoYg5GYX+RZWlx1qPxeVfNKZqiM9jUrFpB+qDdsUQsTN/ PC+1bT6MFN+HftLE4Btq7/QoxinsYgA3iRebdw3l1tbTRhERkcLPt9gO675auEEn84+o DkIx+HQmrGrCWeBKyDSlgD+I5UaOKviMBYq6ndyP+2pd/iA67hYKnOwodcenqmRevoE2 k2jw== X-Gm-Message-State: AOAM533A8hd0rZsZLrb2LSkDzBOrFFFokFgJf0PvKKmmLl/EXzJftCSB RGuYtiOqk8Hfa3oPDRB4Nkeuhm/AdLw5TPUK8zw= X-Google-Smtp-Source: ABdhPJyCwSWEU5JCr0kqNNifxLVLrqFpncRArGWwYqB89CWL/wL711ci9pxXIChUPLzXYXMr8qnijsT5klOeBht3yJ0= X-Received: by 2002:a05:6808:4d9:: with SMTP id a25mr1512698oie.33.1635295620839; Tue, 26 Oct 2021 17:47:00 -0700 (PDT) MIME-Version: 1.0 References: <20211020120726.4022086-1-pizhenwei@bytedance.com> <08757159-1673-5c7b-3efc-e5b54e82d6c3@bytedance.com> <5b718b32-cd92-920e-c474-27b9cafeec60@bytedance.com> In-Reply-To: From: Wanpeng Li Date: Wed, 27 Oct 2021 08:46:49 +0800 Message-ID: Subject: Re: [PATCH] x86/kvm: Introduce boot parameter no-kvm-pvipi To: Sean Christopherson Cc: zhenwei pi , Paolo Bonzini , Jonathan Corbet , Wanpeng Li , LKML , linux-doc@vger.kernel.org Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 27 Oct 2021 at 00:04, Sean Christopherson wrote: > > On Mon, Oct 25, 2021, zhenwei pi wrote: > > Hi, Wanpeng & Sean > > > > Also benchmark redis(by 127.0.0.1) in a guest(2vCPU), 'no-kvm-pvipi' gets > > better performance. > > > > Test env: > > Host side: pin 2vCPU on 2core in a die. > > Guest side: run command: > > taskset -c 1 ./redis-server --appendonly no > > taskset -c 0 ./redis-benchmark -h 127.0.0.1 -d 1024 -n 10000000 -t get > > > > 1> without no-kvm-pvipi: > > redis QPS: 193203.12 requests per second > > kvm_pv_send_ipi exit: ~18K/s > > > > 2> with no-kvm-pvipi: > > redis QPS: 196028.47 requests per second > > avic_incomplete_ipi_interception exit: ~5K/s > > Numbers look sane, but I don't think that adding a guest-side kernel param is > the correct "fix". As evidenced by Wanpeng's tests, PV IPI can outperform AVIC > in overcommit scenarios, and there's also no guarantee that AVIC/APICv is even Our evaluation is a dedicated scenario w/ big VM. The testing from above is a one-sided view. Wanpeng