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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 32403C433EF for ; Wed, 12 Jan 2022 17:40:48 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S243962AbiALRkn (ORCPT ); Wed, 12 Jan 2022 12:40:43 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35462 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1343834AbiALRki (ORCPT ); Wed, 12 Jan 2022 12:40:38 -0500 Received: from mail-ua1-x92e.google.com (mail-ua1-x92e.google.com [IPv6:2607:f8b0:4864:20::92e]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id BC147C061751 for ; Wed, 12 Jan 2022 09:40:37 -0800 (PST) Received: by mail-ua1-x92e.google.com with SMTP id l15so6206593uai.11 for ; Wed, 12 Jan 2022 09:40:37 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=dhM+RzO3xwFuopgokIVID6/QrF7tTW5/nX5Pew1Lc9Q=; b=SyYG7uLNTiZjxR2Z3l5y/XfsC4VwQmx/UbAni3zFA3TB6pm/1c6YxrYZDtGXRXOue3 vp85vFta7lXTLdNX3DwyJzg/Galc+7SpOPngJOvXjApn+XU9otKCpQwKrhrq8lfTuH7S jLUzDBOP/aRViiStBjGc8A9bsYPSFxLUkwij+iHPmrA5hHMUf1ZOmm77v7LlVwYYqzai tmejXr0Z4PQgq1eSBhkvniR4NaOUk85CrQWQDZisE0bMXFJbHXuZ1jMe7w4elzyFiWlS fw4GLWFeuImOaNMtjVUdla30ieN/R+c+CbK2ZFuVZR6bWmTUI6BvzsfpryFoeF6KTuhu QMeA== 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=dhM+RzO3xwFuopgokIVID6/QrF7tTW5/nX5Pew1Lc9Q=; b=ovXKawmUd7tC10eMLHZazL8k9iCJH2GiYAA1N7SYmVoDeAXAPpnctCrFIWADMIn/en rpXbtu8mk3ZlsvhXSbZIT4797eWdoN7/xsTSqHJwYJlAO0kVJTx9gcoO9TYx2Z8MfuJh Qrp76vDqmXMiOBeesdBa66qZlngw4DRerZ49SHoZY4FwI1QRGJv0Fh2O9mhulFvWVl88 Pftc2f1j145lreSw0OllnNTh0wRZyJfYoGryHyZ1owmWJD7gVyEF3fAd2W6n9wb/Fgz7 NcOiV2tXmbQ2URKA6gOgoVcw+JWk4zFncgerOv7lC2zVoHLsMXsaogXv0gCH5Jjo5DLN yabg== X-Gm-Message-State: AOAM533yLee+IF53OSVOvS9KaRQAPaJBHozMYSFCMQy+x4TtjaCHgb5h WakVZUs0KhMfkHaAxBGV7ZkqsAO7/SAyJeFwbebcsA== X-Google-Smtp-Source: ABdhPJwznL0hfPfcEMsiGVpmV5gcIpAD+uBmDTfAurrv7pJYzgxnie/RNnSPOLQWD3kNNt+AL8yF8iQh0VtaIh070hU= X-Received: by 2002:ab0:13c3:: with SMTP id n3mr499265uae.39.1642009236785; Wed, 12 Jan 2022 09:40:36 -0800 (PST) MIME-Version: 1.0 References: <20220110210441.2074798-1-jingzhangos@google.com> <20220110210441.2074798-4-jingzhangos@google.com> <87a6g2tvia.wl-maz@kernel.org> <87sfttrxqv.wl-maz@kernel.org> In-Reply-To: <87sfttrxqv.wl-maz@kernel.org> From: Jing Zhang Date: Wed, 12 Jan 2022 09:40:25 -0800 Message-ID: Subject: Re: [RFC PATCH 3/3] KVM: selftests: Add vgic initialization for dirty log perf test for ARM To: Marc Zyngier Cc: KVM , KVMARM , Will Deacon , Paolo Bonzini , David Matlack , Oliver Upton , Reiji Watanabe , Raghavendra Rao Ananta Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org On Wed, Jan 12, 2022 at 3:37 AM Marc Zyngier wrote: > > On Tue, 11 Jan 2022 22:16:01 +0000, > Jing Zhang wrote: > > > > On Tue, Jan 11, 2022 at 2:30 AM Marc Zyngier wrote: > > > > > > On Mon, 10 Jan 2022 21:04:41 +0000, > > > Jing Zhang wrote: > > > > > > > > For ARM64, if no vgic is setup before the dirty log perf test, the > > > > userspace irqchip would be used, which would affect the dirty log perf > > > > test result. > > > > > > Doesn't it affect *all* performance tests? How much does this change > > > contributes to the performance numbers you give in the cover letter? > > > > > This bottleneck showed up after adding the fast path patch. I didn't > > try other performance tests with this, but I think it is a good idea > > to add a vgic setup for all performance tests. I can post another > > patch later to make it available for all performance tests after > > finishing this one and verifying all other performance tests. > > Below is the test result without adding the vgic setup. It shows > > 20~30% improvement for the different number of vCPUs. > > +-------+------------------------+ > > | #vCPU | dirty memory time (ms) | > > +-------+------------------------+ > > | 1 | 965 | > > +-------+------------------------+ > > | 2 | 1006 | > > +-------+------------------------+ > > | 4 | 1128 | > > +-------+------------------------+ > > | 8 | 2005 | > > +-------+------------------------+ > > | 16 | 3903 | > > +-------+------------------------+ > > | 32 | 7595 | > > +-------+------------------------+ > > | 64 | 15783 | > > +-------+------------------------+ > > So please use these numbers in your cover letter when you repost your > series, as the improvement you'd observe on actual workloads is likely > to be less than what you claim due to this change in the test itself > (in other words, if you are going to benchamark something, don't > change the benchmark halfway). Sure. Will clarify this in the cover letter in future posts. Thanks, Jing > > M. > > -- > Without deviation from the norm, progress is not possible.