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=-0.6 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 D24A5C4332B for ; Mon, 23 Mar 2020 12:10:42 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 9DD8220788 for ; Mon, 23 Mar 2020 12:10:42 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="d1rxfiGy" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 9DD8220788 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:32928 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jGLuj-0000Q4-NK for qemu-devel@archiver.kernel.org; Mon, 23 Mar 2020 08:10:41 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:47566) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jGLu3-0008Mv-BH for qemu-devel@nongnu.org; Mon, 23 Mar 2020 08:10:00 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1jGLu2-0006mc-BW for qemu-devel@nongnu.org; Mon, 23 Mar 2020 08:09:59 -0400 Received: from us-smtp-delivery-74.mimecast.com ([63.128.21.74]:55683) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1jGLu2-0006mS-5j for qemu-devel@nongnu.org; Mon, 23 Mar 2020 08:09:58 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1584965397; 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=/zjd3JETTCHtj2QJfM71AHKLOIO0dheMjXt/59EAgeo=; b=d1rxfiGyCWMwlZVw2cz5r/OuLLjxUuYbtIp8KcUqVJYVknclvGlTgDDoagUXdx9LE8cJbC o3Uf949bEqJc8xLYJmx00XhONJ0XuEFm5wOcVSg2gi9H2Bss7z09etXgsa5rt/pP2ABYLb vvjTBG1RsttzLQjGl9TzI6zo9NSA9BM= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-154-kYBAfH6-MWKJV5gM1bElfA-1; Mon, 23 Mar 2020 08:09:55 -0400 X-MC-Unique: kYBAfH6-MWKJV5gM1bElfA-1 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id D604E800D6C; Mon, 23 Mar 2020 12:09:54 +0000 (UTC) Received: from sirius.home.kraxel.org (ovpn-112-49.ams2.redhat.com [10.36.112.49]) by smtp.corp.redhat.com (Postfix) with ESMTP id 647755DA7C; Mon, 23 Mar 2020 12:09:49 +0000 (UTC) Received: by sirius.home.kraxel.org (Postfix, from userid 1000) id 9E1349DB6; Mon, 23 Mar 2020 13:09:48 +0100 (CET) Date: Mon, 23 Mar 2020 13:09:48 +0100 From: Gerd Hoffmann To: "Michael S. Tsirkin" Subject: Re: [PATCH 00/13] microvm: add acpi support Message-ID: <20200323120948.f6egd7rhfso6276p@sirius.home.kraxel.org> References: <20200319080117.7725-1-kraxel@redhat.com> <20200323065050-mutt-send-email-mst@kernel.org> MIME-Version: 1.0 In-Reply-To: <20200323065050-mutt-send-email-mst@kernel.org> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: quoted-printable Content-Disposition: inline X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 63.128.21.74 X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Eduardo Habkost , Sergio Lopez , qemu-devel@nongnu.org, Paolo Bonzini , Igor Mammedov , Richard Henderson Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On Mon, Mar 23, 2020 at 06:51:10AM -0400, Michael S. Tsirkin wrote: > On Thu, Mar 19, 2020 at 09:01:04AM +0100, Gerd Hoffmann wrote: > > I know that not supporting ACPI in microvm is intentional. If you stil= l > > don't want ACPI this is perfectly fine, you can use the usual -no-acpi > > switch to toggle ACPI support. > >=20 > > These are the advantages you are going to loose then: > >=20 > > (1) virtio-mmio device discovery without command line hacks (tweaking > > the command line is a problem when not using direct kernel boot). > > (2) Better IO-APIC support, we can use IRQ lines 16-23. > > (3) ACPI power button (aka powerdown request) works. > > (4) machine poweroff (aka S5 state) works. >=20 > What is the cost though? How do boot times compare? Well, acpi speeds up booting by one second because this delay ... [ 0.275736] i8042: PNP: No PS/2 controller found. [ 0.275736] i8042: Probing ports directly. [ 1.315447] i8042: No controller found ... goes away, at least with standard distro kernels. When building your own you can probably compile out the driver somehow, even though something seems to select SERIO_I8042 so trying to simply flip CONFIG_SERIO_I8042 to 'n' in .config doesn't work. And a runtime switch seems to not be there either ... So that ruined my plan to just time until the root filesystem is mounted. Decided to use the "i8042: PNP: No PS/2 controller found." line instead for a simple test (just check the kernel log timestamps, three runs each). The ACPI initialization is already done at that point, so it should be useful nevertheless. Here we go: Without acpi: 0.277710 0.278852 0.279520 With acpi: 0.283917 0.284262 0.284836 So the difference is less than 0.01 seconds on my box. cheers, Gerd